Colorado

A subsurface and surface study of the coal-bearing Fruitland Formation

@article{doi103133pp676,
    author = "Fassett, James E. and Hinds, Jim S.",
    title = "Geology and fuel resources of the Fruitland Formation and Kirtland Shale of the San Juan Basin, New Mexico and Colorado",
    year = "1971",
    journal = "USGS professional paper",
    abstract = "A subsurface and surface study of the coal-bearing Fruitland Formation",
    url = "https://doi.org/10.3133/pp676",
    doi = "10.3133/pp676",
    openalex = "W1529334115",
    references = "doi101016s0300957298001105, doi101130mem24, doi1013065ceae56516bb11d78645000102c1865d, doi101306sv22354c7, doi10313370207506, doi1056577ffc1109, doi1056577ffc2104, doi1056577ffc2124, doi1056577ffc2155, openalexw2772929664"
}

A study describing the amount, location, quality, and economic position of low-sulfur strippable coal in the San Juan Basin, northwest New Mexico and southwest Colorado. Study conducted by the New Mexico Bureau of Mines and Mineral Resources for the Air Pollution Control Office of the Environmental Protection Agency. The report is a compendium of short, more or less self-contained papers dealing with the various coal fields and areas, and with other pertinent subjects. For the purposes of study, coal reserves were estimated in two broad categories-those consisting of beds three feet thick or thicker beneath 10-150 ft of overburden, and those in beds five or more feet thick beneath 150-250 ft of overburden. Data were gathered from all available sources and include: published geologic work, original geologic observation, private consultants' reports, logs of test holes drilled by holders of leases and exploration permits, logs of holes drilled by the New Mexico Bureau of Mines and Mineral Resources, reserve calculations furnished by operators, and information from oil and gas tests. The best use was made of whatever data could be found for a particular area; therefore reserve estimates range in reliability from proven tonnages to speculation based on geologic inferences. An effort was made to give an evaluation of the reliability of each estimate. Coal quality was determined from published and unpublished analyses by the U.S. Bureau of Mines, analyses furnished by operators, and U.S. Bureau of Mines analyses of samples collected during the study. The San Juan Basin is a major physiographic subdivision of the Colorado Plateau in northwestern New Mexico and southwestern Colorado. The basin is about 200 mi long (north to south) and 130 mi wide, and includes about 26,000 sq mi. The strippable coal areas lie along the basin's margins-mainly the western and southern-in roughly concentric belts of outcrop of coal-bearing strata of generally Cretaceous age, with rolling, sparsely grassed plains interrupted by low cuestas and mesas, and broad sandy washes. Coal is found in three major zones of the Cretaceous sequence. In ascending order, they are: the Dakota Sandstone, the Mesaverde Group, and the Fruitland Formation; the three are separated by barren strata of greatly varying thickness.

@book{doi1058799m25,
    author = "Shomaker, John W. and Beaumont, Edward C. and Kottlowski, Frank Ε. and Lease, R and Lease, R and W and Allen, J and Balk, R and Atkinson, C and Ward, D and Lemon, R and A and Averitt, Paul and Baltz, E and Jr and Bauer, C and Reeside, J and Jr and Beaumont, E and Dane, C and Sears, J and Boffey, Phillip and Bozanic, Dan and Carver, H and Childs, O and P and O and Crump, Lulie and Yasnowsky, Phillip and Cullins, H and Bowers, W and Bachman, G and Bachman and Wanek, A and Reeside, J and Jr and Darton, N and Donnell, J and Dutton, C and Fassett, J and Feely, H and Kulp, J and Forney, A and Gasior, S and Haynes, W and Kate11, S and Gardner, J and Gary, J and Gilluly, R and Glaser, P and Gluskoter, H and Hopkins, M and Simon, J and Grose, L and Hileman, D and Ward, A and Hilpert, L and Holmes, W and Hopkins, M and Nance, R and Hughes, R and Hunt, W and Pearn, W and Hunt, C and Jacobs, D and Struxness, E and Bowman, C and Kantrowitz, A and M and Kelley, V and Clinton, N and King, V and Wengerd, S and Leonard, J and Cockrell, C and Linden, H and Moench, R and Montgomery, W and Muehlberger, W and Nathan, R and Associates, Inc and O'brien, R and Oil, Gas and Journal, ; and A and Olds, F and Parsons, R and Company and Phillips, J and Pike, W and Jr and Reeside, J and Jr and Rogers, M and Sabin, Floyd and Jr and Santos, E and Schlee, J and Moench, R and Schrader, F",
    title = "Strippable low-sulfur coal resources of the San Juan Basin in New Mexico and Colorado",
    year = "1971",
    abstract = "A study describing the amount, location, quality, and economic position of low-sulfur strippable coal in the San Juan Basin, northwest New Mexico and southwest Colorado. Study conducted by the New Mexico Bureau of Mines and Mineral Resources for the Air Pollution Control Office of the Environmental Protection Agency. The report is a compendium of short, more or less self-contained papers dealing with the various coal fields and areas, and with other pertinent subjects. For the purposes of study, coal reserves were estimated in two broad categories-those consisting of beds three feet thick or thicker beneath 10-150 ft of overburden, and those in beds five or more feet thick beneath 150-250 ft of overburden. Data were gathered from all available sources and include: published geologic work, original geologic observation, private consultants' reports, logs of test holes drilled by holders of leases and exploration permits, logs of holes drilled by the New Mexico Bureau of Mines and Mineral Resources, reserve calculations furnished by operators, and information from oil and gas tests. The best use was made of whatever data could be found for a particular area; therefore reserve estimates range in reliability from proven tonnages to speculation based on geologic inferences. An effort was made to give an evaluation of the reliability of each estimate. Coal quality was determined from published and unpublished analyses by the U.S. Bureau of Mines, analyses furnished by operators, and U.S. Bureau of Mines analyses of samples collected during the study. The San Juan Basin is a major physiographic subdivision of the Colorado Plateau in northwestern New Mexico and southwestern Colorado. The basin is about 200 mi long (north to south) and 130 mi wide, and includes about 26,000 sq mi. The strippable coal areas lie along the basin's margins-mainly the western and southern-in roughly concentric belts of outcrop of coal-bearing strata of generally Cretaceous age, with rolling, sparsely grassed plains interrupted by low cuestas and mesas, and broad sandy washes. Coal is found in three major zones of the Cretaceous sequence. In ascending order, they are: the Dakota Sandstone, the Mesaverde Group, and the Fruitland Formation; the three are separated by barren strata of greatly varying thickness.",
    url = "https://doi.org/10.58799/m-25",
    doi = "10.58799/m-25",
    openalex = "W1526277432",
    references = "doi101130mem24, doi1013065ceae56516bb11d78645000102c1865d, doi1056577ffc1109, doi1056577ffc2124"
}

@misc{fassett1971geology,
    author = "Fassett, James E. and Hinds, Jim S.",
    title = "Geology and fuel resources of the Fruitland Formation and Kirtland Shale of the San Juan Basin, New Mexico and Colorado",
    year = "1971",
    booktitle = "Professional Paper",
    url = "https://doi.org/10.3133/pp676",
    doi = "10.3133/pp676"
}

@misc{fassett1971geology1,
    author = "Fassett, J. E. and Hinds, J. S",
    title = "Geology and fuel resources of the Fruitland Formation and Kirtland Shale of the San Juan Basin, New Mexico and Colorado",
    year = "1971",
    howpublished = "United States Geological Survey, Professional Paper, v. 676; 76 pp",
    note = "talkorigins\_source = {true}; raw\_reference = {Fassett, J. E., and Hinds, J. S., 1971, Geology and fuel resources of the Fruitland Formation and Kirtland Shale of the San Juan Basin, New Mexico and Colorado: United States Geological Survey, Professional Paper, v. 676; 76 pp.}"
}

@article{fassett1975fruitland,
    author = "Fassett, J. E.",
    title = "Fruitland Formation Coal Deposits of San Juan Basin, New Mexico and Colorado: ABSTRACT",
    year = "1975",
    journal = "AAPG Bulletin",
    url = "https://doi.org/10.1306/83d91dad-16c7-11d7-8645000102c1865d",
    doi = "10.1306/83d91dad-16c7-11d7-8645000102c1865d",
    volume = "59"
}

An experiment in an oil field at Rangely, Colorado, has demonstrated the feasibility of earthquake control. Variations in seismicity were produced by controlled variations in the fluid pressure in a seismically active zone. Precise earthquake locations revealed that the earthquakes clustered about a fault trending through a zone of high pore pressure produced by secondary recovery operations. Laboratory measurements of the frictional properties of the reservoir rocks and an in situ stress measurement made near the earthquake zone were used to predict the fluid pressure required to trigger earthquakes on preexisting fractures. Fluid pressure was controlled by alternately injecting and recovering water from wells that penetrated the seismic zone. Fluid pressure was monitored in observation wells, and a computer model of the reservoir was used to infer the fluid pressure distributions in the vicinity of the injection wells. The results of this experiment confirm the predicted effect of fluid pressure on earthquake activity and indicate that earthquakes can be controlled wherever we can control the fluid pressure in a fault zone.

@article{doi101126science19142331230,
    author = "Raleigh, C. B. and Healy, J. H. and Bredehoeft, John",
    title = "An Experiment in Earthquake Control at Rangely, Colorado",
    year = "1976",
    journal = "Science",
    abstract = "An experiment in an oil field at Rangely, Colorado, has demonstrated the feasibility of earthquake control. Variations in seismicity were produced by controlled variations in the fluid pressure in a seismically active zone. Precise earthquake locations revealed that the earthquakes clustered about a fault trending through a zone of high pore pressure produced by secondary recovery operations. Laboratory measurements of the frictional properties of the reservoir rocks and an in situ stress measurement made near the earthquake zone were used to predict the fluid pressure required to trigger earthquakes on preexisting fractures. Fluid pressure was controlled by alternately injecting and recovering water from wells that penetrated the seismic zone. Fluid pressure was monitored in observation wells, and a computer model of the reservoir was used to infer the fluid pressure distributions in the vicinity of the injection wells. The results of this experiment confirm the predicted effect of fluid pressure on earthquake activity and indicate that earthquakes can be controlled wherever we can control the fluid pressure in a fault zone.",
    url = "https://doi.org/10.1126/science.191.4233.1230",
    doi = "10.1126/science.191.4233.1230",
    openalex = "W2081908598",
    references = "doi101029jz069i002p00259, doi101029wr004i005p01069, doi101126science16138481301, doi101130001676061970812875eriots20co2, doi1011370103003, doi101785bssa0630051557, doi103133om41"
}

@inproceedings{fassett1977geology,
    author = "Fassett, James E. and Hinds, J. S.",
    title = "Geology and fuel resources of the Fruitland Formation and Kirtland Shale of the San Juan Basin, New Mexico and Colorado",
    year = "1977",
    booktitle = "San Juan Basin III, northwestern New Mexico",
    url = "https://doi.org/10.56577/ffc-28.207",
    doi = "10.56577/ffc-28.207",
    pages = "207-207"
}

Continental lithosphere is in unstable mechanical equilibrium because its mantle layer is denser than the asthenosphere. If any process such as cracking, slumping, or plume erosion initially provided an elongated conduit connecting the underlying asthenosphere with the base of the continental crust, the dense lithospheric boundary layer could peel away from the crust and sink. An analytic model for sinking velocities at the critical initial time shows that instability occurs if the effective viscosities of the lower continental crust and the rising asthenosphere are no more than 10 19 P. Analogies to subduction suggest that the mature instability would grow laterally at plate tectonic velocities; however, it would be almost aseismic. Loss of the cold mantle boundary layer would cause uplift, increased heat flow, reduced seismic velocities, and perhaps emplacement of basalt flows, mantle diatremes, and granodiorite sills. A one‐dimensional thermal model of the formation of a new boundary layer predicts a half life of about 3×10 7 years for this thermal anomaly and uplift. As an example, the geologic and geophysical data from the Colorado Plateau are shown to be consistent with the hypothesis that it was uplifted by a delamination event 30 m.y. ago and perhaps a second event about 5 m.y. ago.

@article{doi101029jb084ib13p07561,
    author = "Bird, Peter",
    title = "Continental delamination and the Colorado Plateau",
    year = "1979",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Continental lithosphere is in unstable mechanical equilibrium because its mantle layer is denser than the asthenosphere. If any process such as cracking, slumping, or plume erosion initially provided an elongated conduit connecting the underlying asthenosphere with the base of the continental crust, the dense lithospheric boundary layer could peel away from the crust and sink. An analytic model for sinking velocities at the critical initial time shows that instability occurs if the effective viscosities of the lower continental crust and the rising asthenosphere are no more than 10 19 P. Analogies to subduction suggest that the mature instability would grow laterally at plate tectonic velocities; however, it would be almost aseismic. Loss of the cold mantle boundary layer would cause uplift, increased heat flow, reduced seismic velocities, and perhaps emplacement of basalt flows, mantle diatremes, and granodiorite sills. A one‐dimensional thermal model of the formation of a new boundary layer predicts a half life of about 3×10 7 years for this thermal anomaly and uplift. As an example, the geologic and geophysical data from the Colorado Plateau are shown to be consistent with the hypothesis that it was uplifted by a delamination event 30 m.y. ago and perhaps a second event about 5 m.y. ago.",
    url = "https://doi.org/10.1029/jb084ib13p07561",
    doi = "10.1029/jb084ib13p07561",
    openalex = "W2078181124",
    references = "doi101007bf00388953, doi1010160012825272900384, doi1010160040195178901403, doi101029jb075i020p03941, doi101029jb082i036p05705, doi101029jb083ib10p04975, doi101029jb083ib11p05331, doi101029jz064i010p01521, doi101029me001p0259, doi101111j1365246x1975tb00631x, doi101130001676061974851225somfam20co2"
}

@article{doi1023071219834,
    author = "S., F. A. and Croat, Thomas B.",
    title = "Flora of Barro Colorado Island",
    year = "1979",
    journal = "Taxon",
    url = "https://doi.org/10.2307/1219834",
    doi = "10.2307/1219834",
    openalex = "W2090874753"
}

@book{galton1979a2,
    author = "Galton, P. M. and Jensen, J. A",
    title = "A new large theropod dinosaur from the Upper Jurassic of Colorado",
    year = "1979",
    publisher = "Brigham Young University Geological Studies, v. 26, p. 1-12",
    note = "talkorigins\_source = {true}; raw\_reference = {Galton, P. M., and Jensen, J. A., 1979, A new large theropod dinosaur from the Upper Jurassic of Colorado: Brigham Young University Geological Studies, v. 26, p. 1-12.}"
}

@article{doi101038291193a0,
    author = "DePaolo, Donald J.",
    title = "Neodymium isotopes in the Colorado Front Range and crust–mantle evolution in the Proterozoic",
    year = "1981",
    journal = "Nature",
    url = "https://doi.org/10.1038/291193a0",
    doi = "10.1038/291193a0",
    openalex = "W2047364329",
    references = "doi1010160012821x76902193, doi1010160012821x77901005, doi1010160016003266902705, doi1010160016703779901698, doi1010160301926875900017, doi101029gl003i005p00249, doi101029gl003i012p00743, doi101126science16438851229, doi101126science20043451003, doi1011300091761319753297eotmge20co2"
}

ABSTRACT San Juan basin is a roughly circular, asymmetric structural depression located in northwestern New Mexico and southwestern Colorado. Ultimate recoverable reserves of predominantly nonassociated gas (23 tcf, 0.65 × 1012 m3) are present in the structurally low part of the central basin. The major producing intervals are low-permeability sandstone reservoirs in the Upper Cretaceous Dakota Sandstone, Mesaverde Group, and Pictured Cliffs Sandstone. Lesser amounts of oil and/or gas are produced from Pennsylvanian, Jurassic, and Cretaceous rocks along the southern and western flanks of the basin. The gases display a trend of becoming isotopically heavier (δ13C1 values range from –48.7 to –31.4 ‰ and chemically drier (C1/C1-5 values range from 0.75 to 0.99) with increasing depth. These changes are assumed to be the result of thermal cracking processes, and the gases are interpreted to have been generated during the mature and post-mature stages of hydrocarbon generation. However, there is considerable scatter in the data which is interpreted to result from a difference in source rock type. Gases generated from nonmarine (humic) source rocks are isotopically heavier and chemically drier than those generated from marine (sapropelic) source rocks at equivalent levels of maturity. The gases also become isotopically heavier and chemically drier to the northeast, following the trend of increasing maturity of all units in that direction. The increase in maturity is attributed to a combination of greater burial depth and a higher geothermal gradient resulting from batholiths to the north in the San Juan Mountains area. Maximum burial and heat flow occurred during the Oligocene, which probably coincided with peak hydrocarbon generation. Lack of oil in the central basin is believed to be the result of two factors. First, gas in reservoirs such as the Dakota Sandstone may have resulted from thermal cracking of oil generated from marine source rocks during late mature (wet gas-condensate) and post-mature (dry gas) stages of hydrocarbon generation. Second, gas in reservoirs such as Mesaverde Group and Pictured Cliffs Sandstone is nonassociated and probably was generated from nonmarine (coaly) organic matter during the mature and post-mature stages. Minor amounts of condensate, instead of oil, may have been generated from nonmarine source rocks during the mature stage.

@article{doi10130603b5b72c16d111d78645000102c1865d,
    author = "Rice, Dudley D.",
    title = "Relation of Natural Gas Composition to Thermal Maturity and Source Rock Type in San Juan Basin, Northwestern New Mexico and Southwestern Colorado",
    year = "1983",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT San Juan basin is a roughly circular, asymmetric structural depression located in northwestern New Mexico and southwestern Colorado. Ultimate recoverable reserves of predominantly nonassociated gas (23 tcf, 0.65 × 1012 m3) are present in the structurally low part of the central basin. The major producing intervals are low-permeability sandstone reservoirs in the Upper Cretaceous Dakota Sandstone, Mesaverde Group, and Pictured Cliffs Sandstone. Lesser amounts of oil and/or gas are produced from Pennsylvanian, Jurassic, and Cretaceous rocks along the southern and western flanks of the basin. The gases display a trend of becoming isotopically heavier (δ13C1 values range from –48.7 to –31.4 ‰ and chemically drier (C1/C1-5 values range from 0.75 to 0.99) with increasing depth. These changes are assumed to be the result of thermal cracking processes, and the gases are interpreted to have been generated during the mature and post-mature stages of hydrocarbon generation. However, there is considerable scatter in the data which is interpreted to result from a difference in source rock type. Gases generated from nonmarine (humic) source rocks are isotopically heavier and chemically drier than those generated from marine (sapropelic) source rocks at equivalent levels of maturity. The gases also become isotopically heavier and chemically drier to the northeast, following the trend of increasing maturity of all units in that direction. The increase in maturity is attributed to a combination of greater burial depth and a higher geothermal gradient resulting from batholiths to the north in the San Juan Mountains area. Maximum burial and heat flow occurred during the Oligocene, which probably coincided with peak hydrocarbon generation. Lack of oil in the central basin is believed to be the result of two factors. First, gas in reservoirs such as the Dakota Sandstone may have resulted from thermal cracking of oil generated from marine source rocks during late mature (wet gas-condensate) and post-mature (dry gas) stages of hydrocarbon generation. Second, gas in reservoirs such as Mesaverde Group and Pictured Cliffs Sandstone is nonassociated and probably was generated from nonmarine (coaly) organic matter during the mature and post-mature stages. Minor amounts of condensate, instead of oil, may have been generated from nonmarine source rocks during the mature stage.",
    url = "https://doi.org/10.1306/03b5b72c-16d1-11d7-8645000102c1865d",
    doi = "10.1306/03b5b72c-16d1-11d7-8645000102c1865d",
    openalex = "W2014328180",
    references = "doi1056577ffc2124"
}

Liana (woody vine) abundance, height, diameter, and climbing mode were studied in the mature tropical moist forest on Barro Colorado Island, Panama (BCI). Because lianas are capable of extended horizontal as well as vertical growth, sample plots were 100—m 2 cylinders extending from the ground up to the treetops. The plots were randomly located in areas representing different stages of regeneration following treefalls. In order to examine canopy lianas closely, trees in or adjacent to the sample plots were climbed freehand or with the aid of mechanical rope ascenders. Lianas are abundant on BCI and play important roles in forest dynamics. A hectare of old—growth forest had 1597 climbing lianas distributed among 43% of the canopy trees. Trees with a least one liana has higher than random probability of having more than one liana, and individual lianas connected an average of 1.56 canopy trees. In the understory, 22% of the upright plants <2 m tall were lianas, and, depending on the species, between 15 and 90% of these plants were vegetative offshoots (ramets) and not true seedlings (genets). Lianas were most abundant in recent treefall gaps and decreased in abundance with time since last disturbance. Trellis availability was found to be a major factor limiting liana access to the forest canopy. Experimental manipulation of supports and experimental planting of Dioclea reflexa seedlings revealed that trellises consisting of small diameter, closely spaced supports are most abundant on the edges of treefall gaps. Tree and liana stems on the edges of treefall gaps provided a major pathway to the canopy for climbing plants. Trees carrying lianas suffered higher mortality rates and upon falling caused more other trees to fall than did liana—free trees. Few lianas died when their host tree fell, and many grew back to the canopy using the abundant trellises that occur on the edges of treefall gaps. Tree sapling growth rates in treefall gaps and Luehea seemannii growth rates in the canopy were slower where lianas were abundant.

@article{doi1023071937767,
    author = "Putz, Francis E.",
    title = "The Natural History of Lianas on Barro Colorado Island, Panama",
    year = "1984",
    journal = "Ecology",
    abstract = "Liana (woody vine) abundance, height, diameter, and climbing mode were studied in the mature tropical moist forest on Barro Colorado Island, Panama (BCI). Because lianas are capable of extended horizontal as well as vertical growth, sample plots were 100—m 2 cylinders extending from the ground up to the treetops. The plots were randomly located in areas representing different stages of regeneration following treefalls. In order to examine canopy lianas closely, trees in or adjacent to the sample plots were climbed freehand or with the aid of mechanical rope ascenders. Lianas are abundant on BCI and play important roles in forest dynamics. A hectare of old—growth forest had 1597 climbing lianas distributed among 43\% of the canopy trees. Trees with a least one liana has higher than random probability of having more than one liana, and individual lianas connected an average of 1.56 canopy trees. In the understory, 22\% of the upright plants <2 m tall were lianas, and, depending on the species, between 15 and 90\% of these plants were vegetative offshoots (ramets) and not true seedlings (genets). Lianas were most abundant in recent treefall gaps and decreased in abundance with time since last disturbance. Trellis availability was found to be a major factor limiting liana access to the forest canopy. Experimental manipulation of supports and experimental planting of Dioclea reflexa seedlings revealed that trellises consisting of small diameter, closely spaced supports are most abundant on the edges of treefall gaps. Tree and liana stems on the edges of treefall gaps provided a major pathway to the canopy for climbing plants. Trees carrying lianas suffered higher mortality rates and upon falling caused more other trees to fall than did liana—free trees. Few lianas died when their host tree fell, and many grew back to the canopy using the abundant trellises that occur on the edges of treefall gaps. Tree sapling growth rates in treefall gaps and Luehea seemannii growth rates in the canopy were slower where lianas were abundant.",
    url = "https://doi.org/10.2307/1937767",
    doi = "10.2307/1937767",
    openalex = "W2056298642",
    references = "doi101017cbo9780511703010, doi101086284079, doi101139x83133, doi1023071219834, doi1023071934677, doi1023071937003, doi1023071942424, doi1023071942493, doi1023072403444, doi105860choice350270"
}

@misc{jensen1985uncompahgre3,
    author = "Jensen, J. A",
    title = "Uncompahgre dinosaur fauna",
    year = "1985",
    howpublished = "a preliminary report: Great Basin Naturalist, v. 45, p. 710-720",
    note = "talkorigins\_source = {true}; raw\_reference = {Jensen, J. A., 1985, Uncompahgre dinosaur fauna: a preliminary report: Great Basin Naturalist, v. 45, p. 710-720.}"
}

Numerous analytical techniques were applied to determine water quality changes in the San Juan River basin upstream of Shiprock, New Mexico. Eight techniques were used to analyze hydrologic data such as: precipitation, water quality, and streamflow. The eight methods used are: (1) Piper diagram, (2) time-series plot, (3) frequency distribution, (4) box-and-whisker plot, (5) seasonal Kendall test, (6) Wilcoxon rank-sum test, (7) SEASRS procedure, and (8) analysis of flow adjusted, specific conductance data and smoothing. Post-1963 changes in dissolved solids concentration, dissolved potassium concentration, specific conductance, suspended sediment concentration, or suspended sediment load in the San Juan River downstream from the surface coal mines were examined to determine if coal mining was having an effect on the quality of surface water. None of the analytical methods used to analyzed the data showed any increase in dissolved solids concentration, dissolved potassium concentration, or specific conductance in the river downstream from the mines; some of the analytical methods used showed a decrease in dissolved solids concentration and specific conductance. Chaco River, an ephemeral stream tributary to the San Juan River, undergoes changes in water quality due to effluent from a power generation facility. The discharge in the Chaco River contributes about 1.9% of the average annual discharge at the downstream station, San Juan River at Shiprock, NM. The changes in water quality detected at the Chaco River station were not detected at the downstream Shiprock station. It was not possible, with the available data, to identify any effects of the surface coal mines on water quality that were separable from those of urbanization, agriculture, and other cultural and natural changes. In order to determine the specific causes of changes in water quality, it would be necessary to collect additional data at strategically located stations. (Author 's abstract)

@misc{doi103133wri864076,
    author = "Goetz, Carole L. and Abeyta, Cynthia G. and Thomas, Edward V.",
    title = "Application of techniques to identify coal-mine and power-generation effects on surface-water quality, San Juan River basin, New Mexico and Colorado",
    year = "1987",
    abstract = "Numerous analytical techniques were applied to determine water quality changes in the San Juan River basin upstream of Shiprock, New Mexico. Eight techniques were used to analyze hydrologic data such as: precipitation, water quality, and streamflow. The eight methods used are: (1) Piper diagram, (2) time-series plot, (3) frequency distribution, (4) box-and-whisker plot, (5) seasonal Kendall test, (6) Wilcoxon rank-sum test, (7) SEASRS procedure, and (8) analysis of flow adjusted, specific conductance data and smoothing. Post-1963 changes in dissolved solids concentration, dissolved potassium concentration, specific conductance, suspended sediment concentration, or suspended sediment load in the San Juan River downstream from the surface coal mines were examined to determine if coal mining was having an effect on the quality of surface water. None of the analytical methods used to analyzed the data showed any increase in dissolved solids concentration, dissolved potassium concentration, or specific conductance in the river downstream from the mines; some of the analytical methods used showed a decrease in dissolved solids concentration and specific conductance. Chaco River, an ephemeral stream tributary to the San Juan River, undergoes changes in water quality due to effluent from a power generation facility. The discharge in the Chaco River contributes about 1.9\% of the average annual discharge at the downstream station, San Juan River at Shiprock, NM. The changes in water quality detected at the Chaco River station were not detected at the downstream Shiprock station. It was not possible, with the available data, to identify any effects of the surface coal mines on water quality that were separable from those of urbanization, agriculture, and other cultural and natural changes. In order to determine the specific causes of changes in water quality, it would be necessary to collect additional data at strategically located stations. (Author 's abstract)",
    url = "https://doi.org/10.3133/wri864076",
    doi = "10.3133/wri864076",
    openalex = "W105881518",
    references = "fassett1977geology"
}

Cretaceous and Tertiary rocks on the Southern Ute Indian Reservation in southwestern Colorado represent a variety of depositional environments.The sediments of the lower Cretaceous Burro Canyon Formation were deposited on an alluvial plain.Upper Cretaceous rocks consist of marine, coastal, and alluvial deposits that accumulated in or adjacent to the Western Interior seaway.A drop in sea level at the end of the Early Cretaceous caused streams to cut valleys into the top of the Burro Canyon, forming a regional unconformity.Regression of the Early Cretaceous sea was followed by a transgression into southwestern Colorado that resulted in the deposition of the fluvial, deltaic, and marginal-marine sediments of the Upper Cretaceous Dakota Sandstone and overlying marine Mancos Shale.The Mesaverde Group forms a generally northeasterly prograding deltaic and strand-plain wedge that intertongues with the upper part of the underlying Mancos and the lower part of the overlying marine Lewis Shale.The marginal-marine sediments of the Pictured Cliffs Sandstone, which overlie and interfinger with the upper part of the Lewis Shale, were deposited during the final regression of the Western Interior sea from southwestern Colorado near the end of Late Cretaceous time.The Pictured Cliffs is overlain by the alluvial, paludal, and lacustrine deposits of the uppermost Cretaceous Fruitland Formation and Kirtland Shale.Tertiary rocks on the Reservation include parts of the Animas, Nacimiento, and San Jose Formations.These rocks, which are composed of sediments that are mostly fluvial in origin and have northerly sources, are the result of episodic uplift north of the San Juan basin during the early part of the Laramide orogeny.Tertiary dikes, sills,

@article{doi103133pp1505bc,
    author = "Aubrey, W. M. and Molenaar, C. M. and Baird, J.K.",
    title = "Geologic framework and stratigraphy of Cretaceous and Tertiary rocks of the Southern Ute Indian Reservation, southwestern Colorado",
    year = "1991",
    journal = "USGS professional paper",
    abstract = "Cretaceous and Tertiary rocks on the Southern Ute Indian Reservation in southwestern Colorado represent a variety of depositional environments.The sediments of the lower Cretaceous Burro Canyon Formation were deposited on an alluvial plain.Upper Cretaceous rocks consist of marine, coastal, and alluvial deposits that accumulated in or adjacent to the Western Interior seaway.A drop in sea level at the end of the Early Cretaceous caused streams to cut valleys into the top of the Burro Canyon, forming a regional unconformity.Regression of the Early Cretaceous sea was followed by a transgression into southwestern Colorado that resulted in the deposition of the fluvial, deltaic, and marginal-marine sediments of the Upper Cretaceous Dakota Sandstone and overlying marine Mancos Shale.The Mesaverde Group forms a generally northeasterly prograding deltaic and strand-plain wedge that intertongues with the upper part of the underlying Mancos and the lower part of the overlying marine Lewis Shale.The marginal-marine sediments of the Pictured Cliffs Sandstone, which overlie and interfinger with the upper part of the Lewis Shale, were deposited during the final regression of the Western Interior sea from southwestern Colorado near the end of Late Cretaceous time.The Pictured Cliffs is overlain by the alluvial, paludal, and lacustrine deposits of the uppermost Cretaceous Fruitland Formation and Kirtland Shale.Tertiary rocks on the Reservation include parts of the Animas, Nacimiento, and San Jose Formations.These rocks, which are composed of sediments that are mostly fluvial in origin and have northerly sources, are the result of episodic uplift north of the San Juan basin during the early part of the Laramide orogeny.Tertiary dikes, sills,",
    url = "https://doi.org/10.3133/pp1505bc",
    doi = "10.3133/pp1505bc",
    openalex = "W615065558",
    references = "fassett1977geology"
}

@article{doi101016016651629290020w,
    author = "Roberts, Laura N.R. and McCabe, Peter J.",
    title = "Peat accumulation in coastal-plain mires: a model for coals of the Fruitland Formation (Upper Cretaceous) of southern Colorado, USA",
    year = "1992",
    journal = "International Journal of Coal Geology",
    url = "https://doi.org/10.1016/0166-5162(92)90020-w",
    doi = "10.1016/0166-5162(92)90020-w",
    openalex = "W1996700787",
    references = "doi101306sv22354c7"
}

@misc{andayers1994coalbed,
    author = "Ayers, W.B. and Kaiser, W.R.",
    title = "Coalbed Methane in the Upper Cretaceous Fruitland Formation, San Juan Basin, New Mexico and Colorado",
    year = "1994",
    booktitle = "Report Investigation",
    url = "https://doi.org/10.23867/ri0218d",
    doi = "10.23867/ri0218d",
    openalex = "W2971601157"
}

@misc{andayersjr1994coalbed,
    author = "Ayers Jr., W.B.",
    title = "Coalbed Methane in the Upper Cretaceous Fruitland Formation, San Juan Basin, New Mexico and Colorado",
    year = "1994",
    booktitle = "Report Investigation",
    url = "https://doi.org/10.23867/ri2018d",
    doi = "10.23867/ri2018d",
    openalex = "W4301655276"
}

@misc{ayers1994rs31,
    author = "Ayers, Jr., W. B. and Kaiser, W. R.",
    title = "RS-31 Coalbed Methane in the Upper Cretaceous Fruitland Formation, San Juan Basin, New Mexico and Colorado",
    year = "1994",
    url = "https://doi.org/10.58783/cgs.rs31.jxgu1990",
    doi = "10.58783/cgs.rs31.jxgu1990",
    openalex = "W4385538766"
}

Coalbed methane is playing an increasingly important role in meeting the energy needs of the United States. This unconventional gas may supply 4-5% of the domestic natural gas in 1994. The San Juan Basin led the nation in coalbed methane production in 1992, when nearly 2,100 Fruitland coalbed wells produced approximately 447 billion cubic feet (BCF) of coalbed methane - 81% of the total U.S. coalbed methane production of approximately 553 BCF. This publication discusses five areas that relate to controls on the occurrence or producibility of coalbed methane in the San Juan Basin: tectonic setting; depositional setting; fracture patterns in Fruitland coalbeds and adjacent strata; studies of hydrology, thermal maturity, and gas composition; and the integration of geologic and hydrologic studies. The research, funded by the Gas Research Institute and conducted by the Bureau of Economic Geology at the University of Texas at Austin, the Colorado Geologic Survey, and the New Mexico Bureau of Mines and Mineral Resources, was summarized in a topical report (GRI-91/0072) that had limited distribution. This publication includes reviewed papers on the San Juan Basin from that report, but omits two generic papers, and makes the research results more available to geoscientists and engineers.

@misc{crossref1994coalbed,
    title = "Coalbed methane in the Upper Cretaceous Fruitland Formation, San Juan Basin, New Mexico and Colorado",
    year = "1994",
    abstract = "Coalbed methane is playing an increasingly important role in meeting the energy needs of the United States. This unconventional gas may supply 4-5\% of the domestic natural gas in 1994. The San Juan Basin led the nation in coalbed methane production in 1992, when nearly 2,100 Fruitland coalbed wells produced approximately 447 billion cubic feet (BCF) of coalbed methane - 81\% of the total U.S. coalbed methane production of approximately 553 BCF. This publication discusses five areas that relate to controls on the occurrence or producibility of coalbed methane in the San Juan Basin: tectonic setting; depositional setting; fracture patterns in Fruitland coalbeds and adjacent strata; studies of hydrology, thermal maturity, and gas composition; and the integration of geologic and hydrologic studies. The research, funded by the Gas Research Institute and conducted by the Bureau of Economic Geology at the University of Texas at Austin, the Colorado Geologic Survey, and the New Mexico Bureau of Mines and Mineral Resources, was summarized in a topical report (GRI-91/0072) that had limited distribution. This publication includes reviewed papers on the San Juan Basin from that report, but omits two generic papers, and makes the research results more available to geoscientists and engineers.",
    url = "https://doi.org/10.58799/b-146",
    doi = "10.58799/b-146",
    openalex = "W4323766929",
    references = "doi10100797814684275788, doi1010079783642964466, doi1010160016003257907664, doi1010160016703786903467, doi101029jb085ib11p06113, doi1011300016760619881001023papsol23co2, doi1011300016760619881001181piujot23co2, doi10130603b599f416d111d78645000102c1865d, doi101306ad46094a16f711d78645000102c1865d, openalexw1521060394"
}

ABSTRACT The San Juan basin is the most prolific coalbed gas basin in the world with 1992 production exceeding 440 Gcf* (12.4 billion m3), resources of approximately 50 Tcf (1.4 trillion m3), and proved reserves of over 6 Tcf (170 billion m3). Coalbed gas wells with the highest production (initial potential greater than 10 Mcf/day or 0.28 million m3/day) occur in the overpressured, north-central part of the basin. Hydrologic analysis indicates that overpressure in the Fruitland Formation is artesian in origin and represents repressuring that developed during the middle Pliocene. Highly permeable, laterally continuous coal beds override abandoned shoreline Pictured Cliffs sandstones and extend to the elevated recharge area in the northern basin to form a dynamic, regionally interconnected aquifer system. Coal rank and basin hydrodynamics control the composition of Fruitland coalbed gases, which varies significantly across the basin. Chemically dry gases in the north-central part of the basin coincide with meteoric recharge and regional overpressure. The consistency of methane δ13C values across the basin, the presence of isotopically heavy carbon dioxide in coalbed gases and bicarbonate in formation waters, and biodegraded n-alkane distributions of some coal extracts indicate that coalbed gases in the north-central basin are a mixture of thermogenic (25–50%), secondary biogenic (15–30%), and migrated thermogenic (12–60%) gases. Migrated, conventionally and hydrodynamically trapped gases, in-situ generated secondary biogenic gases, and solution gases result in gas contents that plot on or above the coal sorption isotherm. Bacteria transported basinward in groundwater flowing from the elevated northern basin margins metabolized wet gas components, n-alkanes, and organic compounds in the coal and generated secondary biogenic methane and carbon dioxide subsequent to coalification, uplift, erosion, and cooling. These gases may be limited to basin margins, where shallow depths and structural deformation result in higher permeability, or may extend more than 35 mi (56 km) basinward from the recharge zone. The presence of appreciable secondary biogenic gas indicates an active dynamic flow system with overall permeability sufficient for high productivity. Basin hydrogeology, reservoir heterogeneity, location of permeability barriers (no-flow boundaries), and the timing of biogenic gas generation and trap development are critical for exploration and development of unconventional gas resources in organic-rich rocks.

@article{doi101306a25feaa9171b11d78645000102c1865d,
    author = "Scott, W. R. Kaiser Andrew R. and Kaiser, W. R. and Ayers, Walter B.",
    title = "Thermogenic and Secondary Biogenic Gases, San Juan Basin, Colorado and New Mexico—Implications for Coalbed Gas Producibility",
    year = "1994",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT The San Juan basin is the most prolific coalbed gas basin in the world with 1992 production exceeding 440 Gcf* (12.4 billion m3), resources of approximately 50 Tcf (1.4 trillion m3), and proved reserves of over 6 Tcf (170 billion m3). Coalbed gas wells with the highest production (initial potential greater than 10 Mcf/day or 0.28 million m3/day) occur in the overpressured, north-central part of the basin. Hydrologic analysis indicates that overpressure in the Fruitland Formation is artesian in origin and represents repressuring that developed during the middle Pliocene. Highly permeable, laterally continuous coal beds override abandoned shoreline Pictured Cliffs sandstones and extend to the elevated recharge area in the northern basin to form a dynamic, regionally interconnected aquifer system. Coal rank and basin hydrodynamics control the composition of Fruitland coalbed gases, which varies significantly across the basin. Chemically dry gases in the north-central part of the basin coincide with meteoric recharge and regional overpressure. The consistency of methane δ13C values across the basin, the presence of isotopically heavy carbon dioxide in coalbed gases and bicarbonate in formation waters, and biodegraded n-alkane distributions of some coal extracts indicate that coalbed gases in the north-central basin are a mixture of thermogenic (25–50\%), secondary biogenic (15–30\%), and migrated thermogenic (12–60\%) gases. Migrated, conventionally and hydrodynamically trapped gases, in-situ generated secondary biogenic gases, and solution gases result in gas contents that plot on or above the coal sorption isotherm. Bacteria transported basinward in groundwater flowing from the elevated northern basin margins metabolized wet gas components, n-alkanes, and organic compounds in the coal and generated secondary biogenic methane and carbon dioxide subsequent to coalification, uplift, erosion, and cooling. These gases may be limited to basin margins, where shallow depths and structural deformation result in higher permeability, or may extend more than 35 mi (56 km) basinward from the recharge zone. The presence of appreciable secondary biogenic gas indicates an active dynamic flow system with overall permeability sufficient for high productivity. Basin hydrogeology, reservoir heterogeneity, location of permeability barriers (no-flow boundaries), and the timing of biogenic gas generation and trap development are critical for exploration and development of unconventional gas resources in organic-rich rocks.",
    url = "https://doi.org/10.1306/a25feaa9-171b-11d7-8645000102c1865d",
    doi = "10.1306/a25feaa9-171b-11d7-8645000102c1865d",
    openalex = "W2135740024",
    references = "delaune1986methane, doi10100797814684275788, doi1010079783642964466, doi1010160016703786903467, doi1010160146638083900414, doi101016b9780120320011500110, doi101016s0146638086800134, doi101038269209a0, doi1013062f91976516ce11d78645000102c1865d, doi101306ad46094a16f711d78645000102c1865d, doi103133pp676, fassett1971geology, openalexw1558677347"
}

Fragmentary remains of a long-frilled ceratopsian dinosaur from the El Picacho Formation (Maastrichtian) of West Texas pertain to an undescribed form. The remains are, however, insufficient to fully characterize this species. This ceratopsian has long thick squamosals with marginal undulations, nasals lacking a discrete horncore, a thin parietal, and large trihedral epijugals. The braincase has very thick lateral walls, and a well-developed postfrontal foramen. Four species of horned dinosaurs are known from Upper Cretaceous strata of the American Southwest: Pentaceratops sternbergii, Chasmosaurus mariscalensis, Torosaurus utahensis, and the El Picacho ceratopsian. All of these belong to the subfamily Chasmosaurinae.

@article{doi101017s0022336000038427,
    author = "Lehman, Thomas M.",
    title = "A horned dinosaur from the El Picacho Formation of west Texas, and review of ceratopsian dinosaurs from the American southwest",
    year = "1996",
    journal = "Journal of Paleontology",
    abstract = "Fragmentary remains of a long-frilled ceratopsian dinosaur from the El Picacho Formation (Maastrichtian) of West Texas pertain to an undescribed form. The remains are, however, insufficient to fully characterize this species. This ceratopsian has long thick squamosals with marginal undulations, nasals lacking a discrete horncore, a thin parietal, and large trihedral epijugals. The braincase has very thick lateral walls, and a well-developed postfrontal foramen. Four species of horned dinosaurs are known from Upper Cretaceous strata of the American Southwest: Pentaceratops sternbergii, Chasmosaurus mariscalensis, Torosaurus utahensis, and the El Picacho ceratopsian. All of these belong to the subfamily Chasmosaurinae.",
    url = "https://doi.org/10.1017/s0022336000038427",
    doi = "10.1017/s0022336000038427",
    openalex = "W2492024881",
    references = "lozinsky1984late, openalexw2772929664"
}

The prevalence of abnormal biochemical thyroid function reported here is substantial and confirms previous reports in smaller populations. Among patients taking thyroid medication, only 60% were within the normal range of TSH. Modest elevations of TSH corresponded to changes in lipid levels that may affect cardiovascular health. Individual symptoms were not very sensitive, but patients who report multiple thyroid symptoms warrant serum thyroid testing. These results confirm that thyroid dysfunction is common, may often go undetected, and may be associated with adverse health outcomes that can be avoided by serum TSH measurement.

@article{doi101001archinte1604526,
    author = "Canaris, Gay J. and Manowitz, Neil and Mayor, Gilbert H. and Ridgway, E. Chester",
    title = "The Colorado Thyroid Disease Prevalence Study",
    year = "2000",
    journal = "Archives of Internal Medicine",
    abstract = "The prevalence of abnormal biochemical thyroid function reported here is substantial and confirms previous reports in smaller populations. Among patients taking thyroid medication, only 60\% were within the normal range of TSH. Modest elevations of TSH corresponded to changes in lipid levels that may affect cardiovascular health. Individual symptoms were not very sensitive, but patients who report multiple thyroid symptoms warrant serum thyroid testing. These results confirm that thyroid dysfunction is common, may often go undetected, and may be associated with adverse health outcomes that can be avoided by serum TSH measurement.",
    url = "https://doi.org/10.1001/archinte.160.4.526",
    doi = "10.1001/archinte.160.4.526",
    openalex = "W2140936682",
    references = "doi101001archinte14581386, doi101001archinte196503870060154035, doi1010160002934392907827, doi101016s0140673686905970, doi101056nejm199411103311901, doi101111j136522651977tb01340x, doi101111j136522651991tb01739x, doi101210jcem702453, doi101210jcem8233810, doi10732600034819101118"
}

The incidence and types of adverse events in Utah and Colorado in 1992 were similar to those in New York State in 1984. Iatrogenic injury continues to be a significant public health problem. Improving systems of surgical care and drug delivery could substantially reduce the burden of iatrogenic injury.

@article{doi1010970000565020000300000003,
    author = "Thomas, Eric J. and Studdert, David M. and Burstin, Helen and Orav, E. John and Zeena, Timothy and Williams, Elliott J. and Howard, Kevin and Weiler, Paul C. and Brennan, Troyen A.",
    title = "Incidence and Types of Adverse Events and Negligent Care in Utah and Colorado",
    year = "2000",
    journal = "Medical Care",
    abstract = "The incidence and types of adverse events in Utah and Colorado in 1992 were similar to those in New York State in 1984. Iatrogenic injury continues to be a significant public health problem. Improving systems of surgical care and drug delivery could substantially reduce the burden of iatrogenic injury.",
    url = "https://doi.org/10.1097/00005650-200003000-00003",
    doi = "10.1097/00005650-200003000-00003",
    openalex = "W2036561524",
    references = "doi101001jama199503530010049034, doi101001jama274129, doi101001jama274135, doi101001jama2774301, doi101001jama280151311, doi101056nejm199102073240604, doi101056nejm199102073240605, doi102307257982, doi105694j132653771995tb124691x, openalexw2044588535"
}

In the middle Green River Formation of central Nine Mile Canyon, Uinta Basin, Utah, several lacustrine-dominated intervals ∼10 m thick comprise aggradational carbonate parasequence sets and a progradational elastic parasequence. Maximum flooding surfaces are best identified within profundal oil shale that caps some of the elastic parasequences. These lacustrine transgressive systems tracts therefore exhibit parasequence stacking patterns unlike typical marine sequences. Two types of sequence boundary are identified. Type A sequence boundaries display evidence for a basinward shift in facies across a regionally mappable surface that is an angular or, rarely, parallel unconformity, and they typically juxtapose amalgamated braided fluvial channel sandstone (late lowstand systems tract) onto the profundal oil shale. They also bound depositional sequences that show a distinct asymmetry, being dominated by transgressive systems tracts 5-80 m thick. Highstand systems tracts are less than 4 m thick and may be removed completely, by erosion on overlying sequence boundaries. Other surfaces satisfy only some of the standard criteria of sequence boundaries and are termed type B sequence boundaries. Type A sequence boundaries mark pronounced base-level falls following times when the Uinta Lake had merged with a lake in an adjacent basin to form a much deeper lake. Such merging permitted the establishment of a new threshold at higher elevation following lake-level balancing. Type B sequence boundaries are interpreted as marking base-level falls from a barely merged lake or a lake that had an outflow. Over a 200 m stratigraphic thickness, type A sequence boundaries are more common upsection, indicating that, with time, a pluvial climate became more pronounced or that the adjacent lake was more easily filled. Type A sequence boundaries also become angular rather than parallel unconformities upsection, suggesting increased tilting of the basin margin over time. © 2003, SEPM (Society of Sedimentary Geology).

@article{doi101306050103730987,
    author = "Keighley, David and Flint, Stephen S. and Howell, J. A. and Moscariello, Andrea",
    title = "Sequence Stratigraphy in Lacustrine Basins: A Model for Part of the Green River Formation (Eocene), Southwest Uinta Basin, Utah, U.S.A.",
    year = "2003",
    journal = "Journal of Sedimentary Research",
    abstract = "In the middle Green River Formation of central Nine Mile Canyon, Uinta Basin, Utah, several lacustrine-dominated intervals ∼10 m thick comprise aggradational carbonate parasequence sets and a progradational elastic parasequence. Maximum flooding surfaces are best identified within profundal oil shale that caps some of the elastic parasequences. These lacustrine transgressive systems tracts therefore exhibit parasequence stacking patterns unlike typical marine sequences. Two types of sequence boundary are identified. Type A sequence boundaries display evidence for a basinward shift in facies across a regionally mappable surface that is an angular or, rarely, parallel unconformity, and they typically juxtapose amalgamated braided fluvial channel sandstone (late lowstand systems tract) onto the profundal oil shale. They also bound depositional sequences that show a distinct asymmetry, being dominated by transgressive systems tracts 5-80 m thick. Highstand systems tracts are less than 4 m thick and may be removed completely, by erosion on overlying sequence boundaries. Other surfaces satisfy only some of the standard criteria of sequence boundaries and are termed type B sequence boundaries. Type A sequence boundaries mark pronounced base-level falls following times when the Uinta Lake had merged with a lake in an adjacent basin to form a much deeper lake. Such merging permitted the establishment of a new threshold at higher elevation following lake-level balancing. Type B sequence boundaries are interpreted as marking base-level falls from a barely merged lake or a lake that had an outflow. Over a 200 m stratigraphic thickness, type A sequence boundaries are more common upsection, indicating that, with time, a pluvial climate became more pronounced or that the adjacent lake was more easily filled. Type A sequence boundaries also become angular rather than parallel unconformities upsection, suggesting increased tilting of the basin margin over time. © 2003, SEPM (Society of Sedimentary Geology).",
    url = "https://doi.org/10.1306/050103730987",
    doi = "10.1306/050103730987",
    openalex = "W2117559107",
    references = "doi1010160037073888901339, doi1013063b05c3fc172a11d78645000102c1865d, doi101306m41456c20"
}

As part of the 1991 Annual Meeting of the AAP G in Denver, Colorado, two sessions titled "Giant Oil and Gas Fields of the Decade 1990-2000" were held. These sessions represented the fourth of a four-decade series, each commemorating important giant discoveries and resulting in the publication of AAP G Memoirs, rich in their geologic detail:

@incollection{doi101306m78834c10,
    author = "Ayers, Walter B.",
    title = "Coalbed Methane in the Fruitland Formation, San Juan Basin, Western United States",
    year = "2003",
    booktitle = "American Association of Petroleum Geologists eBooks",
    abstract = {As part of the 1991 Annual Meeting of the AAP G in Denver, Colorado, two sessions titled "Giant Oil and Gas Fields of the Decade 1990-2000" were held. These sessions represented the fourth of a four-decade series, each commemorating important giant discoveries and resulting in the publication of AAP G Memoirs, rich in their geologic detail:},
    url = "https://doi.org/10.1306/m78834c10",
    doi = "10.1306/m78834c10",
    openalex = "W1597601005",
    references = "andayersjr1994coalbed"
}

@article{doi101023bclim0000013684136211f,
    author = "Christensen, N. S. and Wood, Andrew W. and Voisin, Nathalie and Lettenmaier, Dennis P. and Palmer, Richard N.",
    title = "The Effects of Climate Change on the Hydrology and Water Resources of the Colorado River Basin",
    year = "2004",
    journal = "Climatic Change",
    url = "https://doi.org/10.1023/b:clim.0000013684.13621.1f",
    doi = "10.1023/b:clim.0000013684.13621.1f",
    openalex = "W2084170744",
    references = "doi101007s003820000079, doi1010160921818195000461, doi101023a1010616428763, doi101023bclim0000013685996099e, doi1010292000wr900330, doi1010292001jd000659, doi10102994jd00483, doi1011751520044220000132339nhscva20co2, doi1011751520044220020153237althbd20co2, doi10230720033020"
}

THE WILLIAMS Fork Formation preserves a diverse dinosaurfauna containing at least nine saurischian and five ornithis-chian species. Among the dinosaur specimens recovered is a par-tial ceratopsian skull (SDMNH 43470) referable to the ceratopsid subfamily Chasmosaurinae (Diem, 1999). Chasmosaurines, or

@article{doi1016660022336020050790251reoscc20co2,
    author = "DIEM, STEVE and Archibald, J. David",
    title = "RANGE EXTENSION OF SOUTHERN CHASMOSAURINE CERATOPSIAN DINOSAURS INTO NORTHWESTERN COLORADO",
    year = "2005",
    journal = "Journal of Paleontology",
    abstract = "THE WILLIAMS Fork Formation preserves a diverse dinosaurfauna containing at least nine saurischian and five ornithis-chian species. Among the dinosaur specimens recovered is a par-tial ceratopsian skull (SDMNH 43470) referable to the ceratopsid subfamily Chasmosaurinae (Diem, 1999). Chasmosaurines, or",
    url = "https://doi.org/10.1666/0022-3360(2005)079<0251:reoscc>2.0.co;2",
    doi = "10.1666/0022-3360(2005)079<0251:reoscc>2.0.co;2",
    openalex = "W2172933657",
    references = "openalexw2343813256, openalexw2772929664"
}

This study explores antibiotic resistance genes (ARGs) as emerging environmental contaminants. The purpose of this study was to investigate the occurrence of ARGs in various environmental compartments in northern Colorado, including Cache La Poudre (Poudre) River sediments, irrigation ditches, dairy lagoons, and the effluents of wastewater recycling and drinking water treatment plants. Additionally, ARG concentrations in the Poudre River sediments were analyzed at three time points at five sites with varying levels of urban/agricultural impact and compared with two previously published time points. It was expected that ARG concentrations would be significantly higher in environments directly impacted by urban/agricultural activity than in pristine and lesser-impacted environments. Polymerase chain reaction (PCR) detection assays were applied to detect the presence/absence of several tetracycline and sulfonamide ARGs. Quantitative real-time PCR was used to further quantify two tetracycline ARGs (tet(W) and tet(O)) and two sulfonamide ARGs (sul(I) and sul(II)). The following trend was observed with respect to ARG concentrations (normalized to eubacterial 16S rRNA genes): dairy lagoon water > irrigation ditch water > urban/agriculturally impacted river sediments (p < 0.0001), except for sul(II), which was absent in ditch water. It was noted that tet(W) and tet(O) were also present in treated drinking water and recycled wastewater, suggesting that these are potential pathways for the spread of ARGs to and from humans. On the basis of this study, there is a need for environmental scientists and engineers to help address the issue of the spread of ARGs in the environment.

@article{doi101021es060413l,
    author = "Pruden, Amy and Pei, Ruoting and Storteboom, Heather and Carlson, Kenneth H.",
    title = "Antibiotic Resistance Genes as Emerging Contaminants: Studies in Northern Colorado",
    year = "2006",
    journal = "Environmental Science \& Technology",
    abstract = "This study explores antibiotic resistance genes (ARGs) as emerging environmental contaminants. The purpose of this study was to investigate the occurrence of ARGs in various environmental compartments in northern Colorado, including Cache La Poudre (Poudre) River sediments, irrigation ditches, dairy lagoons, and the effluents of wastewater recycling and drinking water treatment plants. Additionally, ARG concentrations in the Poudre River sediments were analyzed at three time points at five sites with varying levels of urban/agricultural impact and compared with two previously published time points. It was expected that ARG concentrations would be significantly higher in environments directly impacted by urban/agricultural activity than in pristine and lesser-impacted environments. Polymerase chain reaction (PCR) detection assays were applied to detect the presence/absence of several tetracycline and sulfonamide ARGs. Quantitative real-time PCR was used to further quantify two tetracycline ARGs (tet(W) and tet(O)) and two sulfonamide ARGs (sul(I) and sul(II)). The following trend was observed with respect to ARG concentrations (normalized to eubacterial 16S rRNA genes): dairy lagoon water > irrigation ditch water > urban/agriculturally impacted river sediments (p < 0.0001), except for sul(II), which was absent in ditch water. It was noted that tet(W) and tet(O) were also present in treated drinking water and recycled wastewater, suggesting that these are potential pathways for the spread of ARGs to and from humans. On the basis of this study, there is a need for environmental scientists and engineers to help address the issue of the spread of ARGs in the environment.",
    url = "https://doi.org/10.1021/es060413l",
    doi = "10.1021/es060413l",
    openalex = "W1995274825",
    references = "doi101016s1369527400002411, doi101081abio120005768, doi101111j157469412003tb01073x, doi101126science2795353996, doi101128aem6611460546142000, doi101128aem67122322001, doi1023072669875, doi10310210769986023004323, doi103201eid0304970403, openalexw1512719169"
}

Abstract Three upper Pictured Cliffs Sandstone tongues in the northern part of the San Juan Basin record high-frequency transgressive episodes during the Late Cretaceous and are inferred to have been caused by eustatic sea level rise coincident with differential subsidence. Outcrop and subsurface studies show that each tongue is an amalgamated barrier strand-plain unit up to 100 ft (30 m) thick. Successive upper Pictured Cliffs tongues display an imbricate relation and are offset basinward, reflecting net shoreline progradation northeastward. Upper Pictured Cliffs barrier strand-plain sandstones underlie and bound thickest Fruitland coal seams on the seaward side. Controls on Fruitland coal-seam thickness and continuity are a function of local facies distribution in a coastal-plain setting, shoreline positions related to transgressive-regressive cycles, and basin subsidence. During periods of relative sea level rise, the Pictured Cliffs shoreline was temporarily stabilized, allowing thick, coastal-plain peats to accumulate. Although some coal seams in the lower Fruitland tongue override abandoned Pictured Cliffs shoreline deposits, many pinch out against them. Differences in the degree of continuity of these coal seams relative to coeval shoreline sandstones are attributed to either differential subsidence in the northern part of the basin, multiple episodes of sea level rise, local variations in accommodation and progradation, stabilization of the shoreline by aggrading peat deposits, or a combination of these factors. Fruitland coalbed methane resources and productivity are partly controlled by coal-seam thickness; other important factors include thermal maturity, fracturing, and overpressuring. The dominant production trend occurs in the northern part of the basin and is oriented northwestward, coinciding with the greatest Fruitland net coal thickness. Similar relationships between trends of thick coal seams of coeval origin with stacked shoreface sandstones exist in other Western Interior basins in the United States and serve as models for coalbed methane exploration in other basins of the world.

@article{doi10130603080706040,
    author = "Ambrose, William A. and Ayers, Walter B.",
    title = "Geologic controls on transgressive-regressive cycles in the upper Pictured Cliffs Sandstone and coal geometry in the lower Fruitland Formation, northern San Juan Basin, New Mexico and Colorado",
    year = "2007",
    journal = "AAPG Bulletin",
    abstract = "Abstract Three upper Pictured Cliffs Sandstone tongues in the northern part of the San Juan Basin record high-frequency transgressive episodes during the Late Cretaceous and are inferred to have been caused by eustatic sea level rise coincident with differential subsidence. Outcrop and subsurface studies show that each tongue is an amalgamated barrier strand-plain unit up to 100 ft (30 m) thick. Successive upper Pictured Cliffs tongues display an imbricate relation and are offset basinward, reflecting net shoreline progradation northeastward. Upper Pictured Cliffs barrier strand-plain sandstones underlie and bound thickest Fruitland coal seams on the seaward side. Controls on Fruitland coal-seam thickness and continuity are a function of local facies distribution in a coastal-plain setting, shoreline positions related to transgressive-regressive cycles, and basin subsidence. During periods of relative sea level rise, the Pictured Cliffs shoreline was temporarily stabilized, allowing thick, coastal-plain peats to accumulate. Although some coal seams in the lower Fruitland tongue override abandoned Pictured Cliffs shoreline deposits, many pinch out against them. Differences in the degree of continuity of these coal seams relative to coeval shoreline sandstones are attributed to either differential subsidence in the northern part of the basin, multiple episodes of sea level rise, local variations in accommodation and progradation, stabilization of the shoreline by aggrading peat deposits, or a combination of these factors. Fruitland coalbed methane resources and productivity are partly controlled by coal-seam thickness; other important factors include thermal maturity, fracturing, and overpressuring. The dominant production trend occurs in the northern part of the basin and is oriented northwestward, coinciding with the greatest Fruitland net coal thickness. Similar relationships between trends of thick coal seams of coeval origin with stacked shoreface sandstones exist in other Western Interior basins in the United States and serve as models for coalbed methane exploration in other basins of the world.",
    url = "https://doi.org/10.1306/03080706040",
    doi = "10.1306/03080706040",
    openalex = "W2109215009",
    references = "doi1056577ffc2124"
}

The assessment of caprocks for geologic CO{sub 2} storage is a multi-scale endeavor. Investigation of a regional caprock - the Kirtland Formation, San Juan Basin, USA - at the pore-network scale indicates high capillary sealing capacity and low permeabilities. Core and wellscale data, however, indicate a potential seal bypass system as evidenced by multiple mineralized fractures and methane gas saturations within the caprock. Our interpretation of {sup 4}He concentrations, measured at the top and bottom of the caprock, suggests low fluid fluxes through the caprock: (1) Of the total {sup 4}He produced in situ (i.e., at the locations of sampling) by uranium and thorium decay since deposition of the Kirtland Formation, a large portion still resides in the pore fluids. (2) Simple advection-only and advection-diffusion models, using the measured {sup 4}He concentrations, indicate low permeability ({approx}10-20 m{sup 2} or lower) for the thickness of the Kirtland Formation. These findings, however, do not guarantee the lack of a large-scale bypass system. The measured data, located near the boundary conditions of the models (i.e., the overlying and underlying aquifers), limit our testing of conceptual models and the sensitivity of model parameterization. Thus, we suggest approaches for future studies to better assess the presence or lack of a seal bypass system at this particular site and for other sites in general.

@misc{doi1021721025536,
    author = "Heath, Jason E. and McPherson, Brian and Dewers, Thomas",
    title = "Natural Tracers and Multi-Scale Assessment of Caprock Sealing Behavior: A Case Study of the Kirtland Formation, San Juan Basin",
    year = "2011",
    abstract = "The assessment of caprocks for geologic CO{sub 2} storage is a multi-scale endeavor. Investigation of a regional caprock - the Kirtland Formation, San Juan Basin, USA - at the pore-network scale indicates high capillary sealing capacity and low permeabilities. Core and wellscale data, however, indicate a potential seal bypass system as evidenced by multiple mineralized fractures and methane gas saturations within the caprock. Our interpretation of {sup 4}He concentrations, measured at the top and bottom of the caprock, suggests low fluid fluxes through the caprock: (1) Of the total {sup 4}He produced in situ (i.e., at the locations of sampling) by uranium and thorium decay since deposition of the Kirtland Formation, a large portion still resides in the pore fluids. (2) Simple advection-only and advection-diffusion models, using the measured {sup 4}He concentrations, indicate low permeability ({approx}10-20 m{sup 2} or lower) for the thickness of the Kirtland Formation. These findings, however, do not guarantee the lack of a large-scale bypass system. The measured data, located near the boundary conditions of the models (i.e., the overlying and underlying aquifers), limit our testing of conceptual models and the sensitivity of model parameterization. Thus, we suggest approaches for future studies to better assess the presence or lack of a seal bypass system at this particular site and for other sites in general.",
    url = "https://doi.org/10.2172/1025536",
    doi = "10.2172/1025536",
    openalex = "W224405626",
    references = "crossref1994coalbed"
}

Clinical and serologic evidence indicate that 2 American scientists contracted Zika virus infections while working in Senegal in 2008. One of the scientists transmitted this arbovirus to his wife after his return home. Direct contact is implicated as the transmission route, most likely as a sexually transmitted infection.

@article{doi103201eid1705101939,
    author = "Foy, Brian D. and Kobylinski, Kevin C. and Foy, Joy L. Chilson and Blitvich, Bradley J. and da Rosa, Amélia Travassos and Haddow, Andrew D. and Lanciotti, Robert S. and Tesh, Robert B.",
    title = "Probable Non–Vector-borne Transmission of Zika Virus, Colorado, USA",
    year = "2011",
    journal = "Emerging infectious diseases",
    abstract = "Clinical and serologic evidence indicate that 2 American scientists contracted Zika virus infections while working in Senegal in 2008. One of the scientists transmitted this arbovirus to his wife after his return home. Direct contact is implicated as the transmission route, most likely as a sexually transmitted infection.",
    url = "https://doi.org/10.3201/eid1705.101939",
    doi = "10.3201/eid1705.101939",
    openalex = "W2065276673",
    references = "doi101007bf01556147, doi1010160035920352900424, doi1010160035920356900293, doi1010160035920364902019, doi1010160035920381901000, doi101016jjcv200805005, doi101056nejmoa0805715, doi101086648731, doi103201eid1408080287, doi103201eid1509090442"
}

Recent interest in the availability of deep groundwater resources along the structurally complicated transition between the Colorado Plateau and the Rio Grande rift in north-central New Mexico, resulted in the development of groundwater-flow models that suggested an impact on the Middle Rio Grande Basin (MRGB, also known as the Albuquerque Basin) from long-term pumping of wells that would exploit pre-Cenozoic aquifer units (Melis, 2009).Refinement of the regional conceptual geologic framework of the Colorado Plateau-MRGB transition was done in order to aid in the development of a revised groundwater-flow model of this region by Melis et al. (2011).The refined geologic framework was based on a compilation of previous stratigraphic work, an examination of data from 72 deep wells, and modifications to structure-contour maps of the base of the Upper Cretaceous Dakota Formation (Thaden and Zech, 1984) and the top of Proterozoic basement (Broadhead et al., 2009).The internal structure of the MRGB is dominated by subbasins and buried structural culminations that likely influence flows of deep groundwater.Structural control on the distribution of springs along the western flank of the MRGB is suggested by variations in basin-margin structure and stratal dips.Few springs are found along the highly faulted Laguna bench, whereas springs are common along the faulted eastern front of the Lucero uplift, where strata dip away from the MRGB boundary.Groundwater-flow across faults was examined by projecting juxtaposition seals and conduits across three fault zones that locally define the northwestern structural margin of the MRGB.A preliminary result of the fault juxtaposition analyses suggest discontinuous and discrete windows of groundwater flow along portions of basin-margin faults.

@misc{doi1058799ofr539,
    author = "Connell, Sean D.",
    title = "Preliminary study of the geologic framework of the Colorado Plateau-Middle Rio Grande Basin transition, New Mexico.",
    year = "2011",
    abstract = "Recent interest in the availability of deep groundwater resources along the structurally complicated transition between the Colorado Plateau and the Rio Grande rift in north-central New Mexico, resulted in the development of groundwater-flow models that suggested an impact on the Middle Rio Grande Basin (MRGB, also known as the Albuquerque Basin) from long-term pumping of wells that would exploit pre-Cenozoic aquifer units (Melis, 2009).Refinement of the regional conceptual geologic framework of the Colorado Plateau-MRGB transition was done in order to aid in the development of a revised groundwater-flow model of this region by Melis et al. (2011).The refined geologic framework was based on a compilation of previous stratigraphic work, an examination of data from 72 deep wells, and modifications to structure-contour maps of the base of the Upper Cretaceous Dakota Formation (Thaden and Zech, 1984) and the top of Proterozoic basement (Broadhead et al., 2009).The internal structure of the MRGB is dominated by subbasins and buried structural culminations that likely influence flows of deep groundwater.Structural control on the distribution of springs along the western flank of the MRGB is suggested by variations in basin-margin structure and stratal dips.Few springs are found along the highly faulted Laguna bench, whereas springs are common along the faulted eastern front of the Lucero uplift, where strata dip away from the MRGB boundary.Groundwater-flow across faults was examined by projecting juxtaposition seals and conduits across three fault zones that locally define the northwestern structural margin of the MRGB.A preliminary result of the fault juxtaposition analyses suggest discontinuous and discrete windows of groundwater flow along portions of basin-margin faults.",
    url = "https://doi.org/10.58799/ofr-539",
    doi = "10.58799/ofr-539",
    openalex = "W4383808578",
    references = "doi101016s0300957298001105"
}

@article{doi101016jcoal201202007,
    author = "Wilson, Thomas H. and Wells, Art and Peters, Dwight and Mioduchowski, A. and Martinez, Gabriela and Koperna, George and Akwari, Bill and Heath, Jason E.",
    title = "Fracture and 3D seismic interpretations of the Fruitland Formation and cover strata: Implications for CO2 retention and tracer movement, San Juan Basin Pilot test",
    year = "2012",
    journal = "International Journal of Coal Geology",
    url = "https://doi.org/10.1016/j.coal.2012.02.007",
    doi = "10.1016/j.coal.2012.02.007",
    openalex = "W2136319744",
    references = "andayers1994coalbed"
}

The Lewis Shale Total Petroleum System (TPS) in the San Juan Basin Province contains a continuous gas accumulation in three distinct stratigraphic units deposited in genetically related depositional environments: offshore-marine shales, mudstones, siltstones, and sandstones of the Lewis Shale, and marginal-marine shoreface sandstones and siltstones of both the La Ventana Tongue and the Chacra Tongue of the Cliff House Sandstone. The Lewis Shale was not a completion target in the San Juan Basin (SJB) in early drilling from about the 1950s through 1990. During that time, only 16 wells were completed in the Lewis from natural fracture systems encountered while drilling for deeper reservoir objectives. In 1991, existing wells that penetrated the Lewis Shale were re-entered by petroleum industry operators in order to fracture-stimulate the Lewis and to add Lewis gas production onto preexisting, and presumably often declining, Mesaverde Group production stratigraphically lower in the section. By 1997, approximately 101 Lewis completions had been made, both as re-entries into existing wells and as add-ons to Mesaverde production in new wells. Based on recent industry drilling and completion practices leading to successful gas production from the Lewis and because new geologic models indicate that the Lewis Shale contains both source rocks and reservoir rocks, the Lewis Shale TPS was defined and evaluated as part of this U.S. Geological Survey oil and gas assessment of the San Juan Basin.

@article{doi103133ds69f5,
    author = "Dubiel, Russell F.",
    title = "Geology, sequence stratigraphy, and oil and gas assessment of the Lewis Shale Total Petroleum System, San Juan Basin, New Mexico and Colorado: Chapter 5 in Total petroleum systems and geologic assessment of undiscovered oil and gas resources in the San Juan Basin Province, exclusive of Paleozoic rocks, New Mexico and Colorado",
    year = "2013",
    journal = "Data series",
    abstract = "The Lewis Shale Total Petroleum System (TPS) in the San Juan Basin Province contains a continuous gas accumulation in three distinct stratigraphic units deposited in genetically related depositional environments: offshore-marine shales, mudstones, siltstones, and sandstones of the Lewis Shale, and marginal-marine shoreface sandstones and siltstones of both the La Ventana Tongue and the Chacra Tongue of the Cliff House Sandstone. The Lewis Shale was not a completion target in the San Juan Basin (SJB) in early drilling from about the 1950s through 1990. During that time, only 16 wells were completed in the Lewis from natural fracture systems encountered while drilling for deeper reservoir objectives. In 1991, existing wells that penetrated the Lewis Shale were re-entered by petroleum industry operators in order to fracture-stimulate the Lewis and to add Lewis gas production onto preexisting, and presumably often declining, Mesaverde Group production stratigraphically lower in the section. By 1997, approximately 101 Lewis completions had been made, both as re-entries into existing wells and as add-ons to Mesaverde production in new wells. Based on recent industry drilling and completion practices leading to successful gas production from the Lewis and because new geologic models indicate that the Lewis Shale contains both source rocks and reservoir rocks, the Lewis Shale TPS was defined and evaluated as part of this U.S. Geological Survey oil and gas assessment of the San Juan Basin.",
    url = "https://doi.org/10.3133/ds69f5",
    doi = "10.3133/ds69f5",
    openalex = "W138191870",
    references = "doi101016s0300957298001105"
}

The Fruitland Total Petroleum System (TPS) of the San Juan Basin Province includes all genetically related hydrocarbons generated from coal beds and organic-rich shales in the Cretaceous Fruitland Formation. Coal beds are considered to be the primary source of the hydrocarbons. Potential reservoir rocks in the Fruitland TPS consist of the Upper Cretaceous Pictured Cliffs Sandstone, Fruitland Formation (both sandstone and coal beds), and the Farmington Sandstone Member of the Kirtland Formation, and the Tertiary Ojo Alamo Sandstone, and Animas, Nacimiento, and San Jose Formations. Analysis of the geochemistry of Fruitland coal-bed gas and co-produced water suggests that hydrocarbons in Fruitland coal beds began to form early in the depositional history of the Fruitland Formation with the generation of early microbial gas. Source rocks in the Fruitland entered the oil generation zone in the late Eocene and continued to generate minor oil and large quantities of thermogenic gas into middle Miocene time. Near the end of the Miocene, thermogenic hydrocarbon generation and subsidence in the San Juan Basin ceased, and the basin was uplifted and differentially eroded. Late-stage (secondary) microbial gas has been documented in Fruitland coal-bed reservoirs and was formed by microbial reduction of carbon dioxide during introduction of groundwater in the late Pliocene and Pleistocene. Most of this late-stage microbial gas is found just downdip from the northern, western, and southern Fruitland outcrops. The northern part of the Fruitland Formation is overpressured as a result of artesian conditions established in the Pliocene or Pleistocene. South and east of the overpressured area, the Fruitland is either normally pressured or underpressured. Four assessment units (AU) were defined in the Fruitland TPS. Of the four AUs, one consists of conventional gas accumulations and the other three are continuous-type gas accumulations: Tertiary Conventional Gas AU, Pictured Cliffs Continuous Gas AU, Basin Fruitland Coalbed Gas (CBG) AU, and Fruitland Fairway CBG AU. No oil resources that have the potential for additions to reserves in the next 30 years were estimated for this TPS. Gas resources that have the potential for additions to reserves in the next 30 years are estimated at a mean of 29.3 trillion cubic feet of gas (TCFG). Of this amount, 23.58 TCFG will come from coal-bed gas accumulations and 83.1 percent of this total is estimated to come from the Basin Fruitland CBG AU. The remaining 5.72 TCFG is allocated to continuous-type gas accumulations (5.64 TCFG) and conventional gas accumulations (0.08 TCFG). Although the Fruitland Fairway CBG AU has produced the most significant amount of coal-bed gas to date, the area of the AU is limited. New potentially productive wells will come from infill drilling, and the number of these wells will be limited by effective drainage area. Total natural gas liquids (NGL) that have the potential for additions to reserves in the next 30 years are estimated at a mean of 17.76 million barrels. Of this amount, 16.92 million barrels will come from the Pictured Cliffs Continuous Gas AU and the remainder from the Tertiary Conventional Gas AU.

@article{doi103133ds69f6,
    author = "Ridgley, Jennie L. and Condon, Steven M. and Hatch, J.R.",
    title = "Geology and oil and gas assessment of the Fruitland Total Petroleum System, San Juan Basin, New Mexico and Colorado: Chapter 6 in Geology and Oil and Gas Assessment of the Fruitland Total Petroleum System, San Juan Basin, New Mexico and Colorado",
    year = "2013",
    journal = "Data series",
    abstract = "The Fruitland Total Petroleum System (TPS) of the San Juan Basin Province includes all genetically related hydrocarbons generated from coal beds and organic-rich shales in the Cretaceous Fruitland Formation. Coal beds are considered to be the primary source of the hydrocarbons. Potential reservoir rocks in the Fruitland TPS consist of the Upper Cretaceous Pictured Cliffs Sandstone, Fruitland Formation (both sandstone and coal beds), and the Farmington Sandstone Member of the Kirtland Formation, and the Tertiary Ojo Alamo Sandstone, and Animas, Nacimiento, and San Jose Formations. Analysis of the geochemistry of Fruitland coal-bed gas and co-produced water suggests that hydrocarbons in Fruitland coal beds began to form early in the depositional history of the Fruitland Formation with the generation of early microbial gas. Source rocks in the Fruitland entered the oil generation zone in the late Eocene and continued to generate minor oil and large quantities of thermogenic gas into middle Miocene time. Near the end of the Miocene, thermogenic hydrocarbon generation and subsidence in the San Juan Basin ceased, and the basin was uplifted and differentially eroded. Late-stage (secondary) microbial gas has been documented in Fruitland coal-bed reservoirs and was formed by microbial reduction of carbon dioxide during introduction of groundwater in the late Pliocene and Pleistocene. Most of this late-stage microbial gas is found just downdip from the northern, western, and southern Fruitland outcrops. The northern part of the Fruitland Formation is overpressured as a result of artesian conditions established in the Pliocene or Pleistocene. South and east of the overpressured area, the Fruitland is either normally pressured or underpressured. Four assessment units (AU) were defined in the Fruitland TPS. Of the four AUs, one consists of conventional gas accumulations and the other three are continuous-type gas accumulations: Tertiary Conventional Gas AU, Pictured Cliffs Continuous Gas AU, Basin Fruitland Coalbed Gas (CBG) AU, and Fruitland Fairway CBG AU. No oil resources that have the potential for additions to reserves in the next 30 years were estimated for this TPS. Gas resources that have the potential for additions to reserves in the next 30 years are estimated at a mean of 29.3 trillion cubic feet of gas (TCFG). Of this amount, 23.58 TCFG will come from coal-bed gas accumulations and 83.1 percent of this total is estimated to come from the Basin Fruitland CBG AU. The remaining 5.72 TCFG is allocated to continuous-type gas accumulations (5.64 TCFG) and conventional gas accumulations (0.08 TCFG). Although the Fruitland Fairway CBG AU has produced the most significant amount of coal-bed gas to date, the area of the AU is limited. New potentially productive wells will come from infill drilling, and the number of these wells will be limited by effective drainage area. Total natural gas liquids (NGL) that have the potential for additions to reserves in the next 30 years are estimated at a mean of 17.76 million barrels. Of this amount, 16.92 million barrels will come from the Pictured Cliffs Continuous Gas AU and the remainder from the Tertiary Conventional Gas AU.",
    url = "https://doi.org/10.3133/ds69f6",
    doi = "10.3133/ds69f6",
    openalex = "W1560821842",
    references = "fassett1977geology"
}

A new ankylosaurid (Ankylosauria: Dinosauria), Ziapelta sanjuanensis, gen. et sp. nov., is based on a complete skull, an incomplete first cervical half ring, a possible fragment of the second cervical half ring, and additional fragmentary osteoderms. The holotype specimen is from the Upper Cretaceous (Upper Campanian, Kirtlandian Land-Vertebrate Age) Kirtland Formation (De-na-zin Member) at Hunter Wash, San Juan Basin, in northwestern New Mexico, USA. Diagnostic characters of Ziapelta include: a large, prominent triangular median nasal caputegulum; a mixture of flat and bulbous frontonasal caputegulae; ventrolaterally oriented squamosal horns with a sharp, prominent dorsal keel; and the ventral surface of basicranium with three prominent anteroposteriorly oriented fossae. A phylogenetic analysis suggests that Ziapelta is not closely related to the other ankylosaurid from the De-na-zin Member, Nodocephalosaurus, but allies it to the northern North American ankylosaurids Ankylosaurus, Anodontosaurus, Euoplocephalus, Dyoplosaurus, and Scolosaurus.

@article{doi101371journalpone0108804,
    author = "Arbour, Victoria M. and Burns, Michael E. and Sullivan, Robert M. and Lucas, Spencer G. and Cantrell, Amanda K. and Fry, Joshua and Suazo, Thomas L.",
    title = "A New Ankylosaurid Dinosaur from the Upper Cretaceous (Kirtlandian) of New Mexico with Implications for Ankylosaurid Diversity in the Upper Cretaceous of Western North America",
    year = "2014",
    journal = "PLoS ONE",
    abstract = "A new ankylosaurid (Ankylosauria: Dinosauria), Ziapelta sanjuanensis, gen. et sp. nov., is based on a complete skull, an incomplete first cervical half ring, a possible fragment of the second cervical half ring, and additional fragmentary osteoderms. The holotype specimen is from the Upper Cretaceous (Upper Campanian, Kirtlandian Land-Vertebrate Age) Kirtland Formation (De-na-zin Member) at Hunter Wash, San Juan Basin, in northwestern New Mexico, USA. Diagnostic characters of Ziapelta include: a large, prominent triangular median nasal caputegulum; a mixture of flat and bulbous frontonasal caputegulae; ventrolaterally oriented squamosal horns with a sharp, prominent dorsal keel; and the ventral surface of basicranium with three prominent anteroposteriorly oriented fossae. A phylogenetic analysis suggests that Ziapelta is not closely related to the other ankylosaurid from the De-na-zin Member, Nodocephalosaurus, but allies it to the northern North American ankylosaurids Ankylosaurus, Anodontosaurus, Euoplocephalus, Dyoplosaurus, and Scolosaurus.",
    url = "https://doi.org/10.1371/journal.pone.0108804",
    doi = "10.1371/journal.pone.0108804",
    openalex = "W2016402442",
    references = "doi101080147720192011569091, doi101098rspl18870117, doi101111j10960031200800217x, doi101139e2012035, doi101371journalpone0012292, doi101371journalpone0062421, doi105860choice393984, doi105860choice514447, fassett1977geology, openalexw3215057009, openalexw632975244"
}

from the upper Judith River Formation fills a gap in the ankylosaurine stratigraphic and geographical record in North America, and further highlights that Campanian ankylosaurines were undergoing rapid evolution and stratigraphic succession of taxa as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.

@article{doi101098rsos161086,
    author = "Arbour, Victoria M. and Evans, David C.",
    title = "A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation",
    year = "2017",
    journal = "Royal Society Open Science",
    abstract = "from the upper Judith River Formation fills a gap in the ankylosaurine stratigraphic and geographical record in North America, and further highlights that Campanian ankylosaurines were undergoing rapid evolution and stratigraphic succession of taxa as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.",
    url = "https://doi.org/10.1098/rsos.161086",
    doi = "10.1098/rsos.161086",
    openalex = "W2613812864",
    references = "crossref1998encyclopedia, doi101007s125490110068y, doi101016jpalaeo200902007, doi101038378774a0, doi101086684289, doi101098rspl18870117, doi101111cla12160, doi101111j10960031200800217x, doi101111j10963642200900617x, doi101139e93016, doi101186s1289801601068, doi101371journalpone0108804, doi102110palo2014084, doi105860choice353642, doi105860choice393984, doi105860choice435902, openalexw3215057009"
}

Cretaceous through Eocene strata of the Four Corners region provide an excellent record of changes in sediment provenance from Sevier thin-skinned thrusting through the formation of Laramide block uplifts and intra-foreland basins. During the ca. 125-50 Ma timespan, the San Juan Basin was flanked by the Sevier thrust belt to the west, the Mogollon highlands rift shoulder to the southwest, and was influenced by (ca. 75-50 Ma) Laramide tectonism, ultimately preserving a >6000 ft (>2000 m) sequence of continental, marginalmarine, and offshore marine sediments. In order to decipher the influences of these tectonic features on sediment delivery to the area, we evaluated 3228 U-Pb laser analyses from 32 detrital-zircon samples from across the entire San Juan Basin, of which 1520 analyses from 16 samples are newly reported herein. The detrital-zircon results indicate four stratigraphic intervals with internally consistent age peaks: (1) Lower Cretaceous Burro Canyon Formation, (2) Turonian (93.9-89.8 Ma) Gallup Sandstone through Campanian (83.6-72.1 Ma) Lewis Shale, (3) Campanian Pictured Cliffs Sandstone through Campanian Fruitland Formation, and (4) Campanian Kirtland Sandstone through Lower Eocene (56.0-47.8 Ma) San Jose Formation. Statistical analysis of the detrital-zircon results, in conjunction with paleocurrent data, reveals three distinct changes in sediment provenance. The first transition, between the Burro Canyon Formation and the Gallup Sandstone, reflects a change from predominantly reworked sediment from the Sevier thrust front, including uplifted Paleozoic sediments and Mesozoic eolian sandstones, to a mixed signature indicating both Sevier and Mogollon derivation. Deposition of the Pictured Cliffs Sandstone at ca. 75 Ma marks the beginning of the second transition and is indicated by the spate of near-depositional-age zircons, likely derived from the Laramide porphyry copper province of southern Arizona and southwestern New Mexico. Paleoflow indicators suggest the third change in provenance was complete by 65 Ma as recorded by the deposition of the Paleocene Ojo Alamo Sandstone. However, our new U-Pb detrital-zircon results indicate this transition initiated ~8 m.y. earlier during deposition of the Campanian Kirtland Formation beginning ca. 73 Ma. This final change in provenance is interpreted to reflect the unroofing of surrounding Laramide basement blocks and a switch to local derivation. At this time, sediment entering the San Juan Basin was largely being generated from the nearby San Juan Mountains to the north-northwest, including uplift associated with early phases of Colorado mineral belt magmatism. Thus, the detrital-zircon spectra in the San Juan Basin document the transition from initial reworking of the Paleozoic and Mesozoic cratonal blanket to unroofing of distant basement-cored uplifts and Laramide plutonic rocks, then to more local Laramide uplifts.

@article{doi101130ges014851,
    author = "Pecha, Mark and Gehrels, George E. and Karlstrom, Karl E. and Dickinson, William R. and Donahue, Magdalena S. and Gonzales, David A. and Blum, Michael D.",
    title = "Provenance of Cretaceous through Eocene strata of the Four Corners region: Insights from detrital zircons in the San Juan Basin, New Mexico and Colorado",
    year = "2018",
    journal = "Geosphere",
    abstract = "Cretaceous through Eocene strata of the Four Corners region provide an excellent record of changes in sediment provenance from Sevier thin-skinned thrusting through the formation of Laramide block uplifts and intra-foreland basins. During the ca. 125-50 Ma timespan, the San Juan Basin was flanked by the Sevier thrust belt to the west, the Mogollon highlands rift shoulder to the southwest, and was influenced by (ca. 75-50 Ma) Laramide tectonism, ultimately preserving a >6000 ft (>2000 m) sequence of continental, marginalmarine, and offshore marine sediments. In order to decipher the influences of these tectonic features on sediment delivery to the area, we evaluated 3228 U-Pb laser analyses from 32 detrital-zircon samples from across the entire San Juan Basin, of which 1520 analyses from 16 samples are newly reported herein. The detrital-zircon results indicate four stratigraphic intervals with internally consistent age peaks: (1) Lower Cretaceous Burro Canyon Formation, (2) Turonian (93.9-89.8 Ma) Gallup Sandstone through Campanian (83.6-72.1 Ma) Lewis Shale, (3) Campanian Pictured Cliffs Sandstone through Campanian Fruitland Formation, and (4) Campanian Kirtland Sandstone through Lower Eocene (56.0-47.8 Ma) San Jose Formation. Statistical analysis of the detrital-zircon results, in conjunction with paleocurrent data, reveals three distinct changes in sediment provenance. The first transition, between the Burro Canyon Formation and the Gallup Sandstone, reflects a change from predominantly reworked sediment from the Sevier thrust front, including uplifted Paleozoic sediments and Mesozoic eolian sandstones, to a mixed signature indicating both Sevier and Mogollon derivation. Deposition of the Pictured Cliffs Sandstone at ca. 75 Ma marks the beginning of the second transition and is indicated by the spate of near-depositional-age zircons, likely derived from the Laramide porphyry copper province of southern Arizona and southwestern New Mexico. Paleoflow indicators suggest the third change in provenance was complete by 65 Ma as recorded by the deposition of the Paleocene Ojo Alamo Sandstone. However, our new U-Pb detrital-zircon results indicate this transition initiated \textasciitilde 8 m.y. earlier during deposition of the Campanian Kirtland Formation beginning ca. 73 Ma. This final change in provenance is interpreted to reflect the unroofing of surrounding Laramide basement blocks and a switch to local derivation. At this time, sediment entering the San Juan Basin was largely being generated from the nearby San Juan Mountains to the north-northwest, including uplift associated with early phases of Colorado mineral belt magmatism. Thus, the detrital-zircon spectra in the San Juan Basin document the transition from initial reworking of the Paleozoic and Mesozoic cratonal blanket to unroofing of distant basement-cored uplifts and Laramide plutonic rocks, then to more local Laramide uplifts.",
    url = "https://doi.org/10.1130/ges01485.1",
    doi = "10.1130/ges01485.1",
    openalex = "W2791464024",
    references = "doi1056577ffc2124"
}

ABSTRACT The lacustrine shale of the Upper Cretaceous Qingshankou Formation is the principal prospective unconventional target lithology, acting as source, reservoir, and seal. Lithofacies and associated storage capacity are two significant factors in shale oil prospectivity. This paper describes an investigation of the lower Qingshankou Formation lacustrine shale based on detailed description and analysis of cores, shale lithofacies characteristics, depositional setting, and stacking patterns. Seven lithofacies are recognized based on organic matter content, sedimentary structure, and mineralogy, all exhibiting rapid vertical and lateral changes controlled by the depositional setting and basin evolution. An overall trend from shallow-water to deep-water depositional environments is interpreted from the characteristics of the infilling sequences, characterized by increasing total organic carbon (TOC) and total clay content and decreasing layer thickness (i.e., from bedded to laminated then to massive sedimentary structures). Periods of deposition during shallowing cycles show a reverse trend in the sedimentary characteristics described above. The sedimentary rocks in the studied interval show three complete short-term cycles, each one containing progressive and regressive system tracts. Massive siliceous mudstones with both high and moderate TOC are considered to have the best hydrocarbon generation potential. Laminated siliceous mudstones, bedded siltstones, and calcareous mudstones with moderate and low TOC could have the same high hydrocarbon saturations as the high-TOC massive siliceous mudstones, but these lithologies contain more brittle minerals than the massive mudstones. Several siltstone samples show low or zero saturation of in situ hydrocarbons; this is considered to be related to a combination of fair to poor hydrocarbon generation potential and extremely low permeability, limiting migration. Moderate-TOC laminated siliceous mudstones were also observed to have connective pore-fracture networks. It can be demonstrated that successive thick sequences of moderate-TOC laminated siliceous mudstones, showing high volumes of hydrocarbon in situ, a high mineral brittleness index, and good permeability, combine to form shale oil exploration “sweet spots.”

@article{doi10130608031817416,
    author = "Liu, Bo and Wang, Haoli and Fu, Xiaofei and Bai, Yunfeng and Bai, Longhui and Jia, Mengcheng and He, Bo",
    title = "Lithofacies and depositional setting of a highly prospective lacustrine shale oil succession from the Upper Cretaceous Qingshankou Formation in the Gulong sag, northern Songliao Basin, northeast China",
    year = "2019",
    journal = "AAPG Bulletin",
    abstract = "ABSTRACT The lacustrine shale of the Upper Cretaceous Qingshankou Formation is the principal prospective unconventional target lithology, acting as source, reservoir, and seal. Lithofacies and associated storage capacity are two significant factors in shale oil prospectivity. This paper describes an investigation of the lower Qingshankou Formation lacustrine shale based on detailed description and analysis of cores, shale lithofacies characteristics, depositional setting, and stacking patterns. Seven lithofacies are recognized based on organic matter content, sedimentary structure, and mineralogy, all exhibiting rapid vertical and lateral changes controlled by the depositional setting and basin evolution. An overall trend from shallow-water to deep-water depositional environments is interpreted from the characteristics of the infilling sequences, characterized by increasing total organic carbon (TOC) and total clay content and decreasing layer thickness (i.e., from bedded to laminated then to massive sedimentary structures). Periods of deposition during shallowing cycles show a reverse trend in the sedimentary characteristics described above. The sedimentary rocks in the studied interval show three complete short-term cycles, each one containing progressive and regressive system tracts. Massive siliceous mudstones with both high and moderate TOC are considered to have the best hydrocarbon generation potential. Laminated siliceous mudstones, bedded siltstones, and calcareous mudstones with moderate and low TOC could have the same high hydrocarbon saturations as the high-TOC massive siliceous mudstones, but these lithologies contain more brittle minerals than the massive mudstones. Several siltstone samples show low or zero saturation of in situ hydrocarbons; this is considered to be related to a combination of fair to poor hydrocarbon generation potential and extremely low permeability, limiting migration. Moderate-TOC laminated siliceous mudstones were also observed to have connective pore-fracture networks. It can be demonstrated that successive thick sequences of moderate-TOC laminated siliceous mudstones, showing high volumes of hydrocarbon in situ, a high mineral brittleness index, and good permeability, combine to form shale oil exploration “sweet spots.”",
    url = "https://doi.org/10.1306/08031817416",
    doi = "10.1306/08031817416",
    openalex = "W2890551816",
    references = "doi101016jcageo201207011, doi101130ges006191, doi10130607231212048, doi1013060c9b238f171011d78645000102c1865d"
}

In 2014, a satellite-based map of regional anomalies of atmospheric methane (CH4) column retrievals singled out the fossil fuel rich San Juan Basin (SJB) as the biggest CH4 regional anomaly (“hot spot”) in the United States. Over a 3-week period in April 2015, we conducted ground and airborne atmospheric measurements to investigate daily wind regimes and CH4 emissions in this region of SW Colorado and NW New Mexico. The SJB, similar to other topographical basins with local sources, experienced elevated surface air pollution under low wind and surface temperature inversion at night and early morning. Survey drives in the basin identified multiple CH4 and ethane (C2H6) sources with distinct C2H6-to-CH4 emission plume ratios for coal bed methane (CBM), natural gas, oil, and coal production operations. Air samples influenced by gas seepage from the Fruitland coal formation outcrop in La Plata County, CO, had enhanced CH4, with no C2-5 light alkane enhancements. In situ fast-response data from seven basin survey flights, all with westerly winds, were used to map and attribute the detected C2H6 and CH4 emission plumes. C2H6-to-CH4 plume enhancement correlation slopes increased from north to south, reflecting the composition of the natural gas and/or CBM extracted in different parts of the basin. Nearly 75% of the total detected CH4 and 85% of the total detected C2H6 hot spot were located in New Mexico. Emissions from CBM and natural gas operations contributed 66% to 75% of the CH4 hot spot. Emissions from oil operations in New Mexico contributed 5% to 6% of the CH4 hot spot and 8% to 14% of the C2H6 hot spot. Seepage from the Fruitland coal outcrop in Colorado contributed at most 8% of the total detected CH4, while gas venting from the San Juan underground coal mine contributed &lt;2%.

@article{doi101525elementa038,
    author = "Pétron, Gabrielle and Miller, B. R. and Vaughn, Bruce H. and Thorley, Eryka and Kofler, J. and Mielke-Maday, I. and Sherwood, Owen A. and Dlugokencky, E. J. and Hall, B. D. and Schwietzke, Stefan and Conley, S. A. and Peischl, Jeff and Lang, Patricia and Moglia, Eric and Crotwell, Molly and Crotwell, Andrew M. and Sweeney, Colm and Newberger, T. and Wolter, S. and Kitzis, Duane and Bianco, Laura and King, C. W. and Coleman, Timothy A. and White, Allen B. and Rhodes, Michael E. and Tans, Pieter P. and Schnell, R. C.",
    title = "Investigating large methane enhancements in the U.S. San Juan Basin",
    year = "2020",
    journal = "Elementa Science of the Anthropocene",
    abstract = "In 2014, a satellite-based map of regional anomalies of atmospheric methane (CH4) column retrievals singled out the fossil fuel rich San Juan Basin (SJB) as the biggest CH4 regional anomaly (“hot spot”) in the United States. Over a 3-week period in April 2015, we conducted ground and airborne atmospheric measurements to investigate daily wind regimes and CH4 emissions in this region of SW Colorado and NW New Mexico. The SJB, similar to other topographical basins with local sources, experienced elevated surface air pollution under low wind and surface temperature inversion at night and early morning. Survey drives in the basin identified multiple CH4 and ethane (C2H6) sources with distinct C2H6-to-CH4 emission plume ratios for coal bed methane (CBM), natural gas, oil, and coal production operations. Air samples influenced by gas seepage from the Fruitland coal formation outcrop in La Plata County, CO, had enhanced CH4, with no C2-5 light alkane enhancements. In situ fast-response data from seven basin survey flights, all with westerly winds, were used to map and attribute the detected C2H6 and CH4 emission plumes. C2H6-to-CH4 plume enhancement correlation slopes increased from north to south, reflecting the composition of the natural gas and/or CBM extracted in different parts of the basin. Nearly 75\% of the total detected CH4 and 85\% of the total detected C2H6 hot spot were located in New Mexico. Emissions from CBM and natural gas operations contributed 66\% to 75\% of the CH4 hot spot. Emissions from oil operations in New Mexico contributed 5\% to 6\% of the CH4 hot spot and 8\% to 14\% of the C2H6 hot spot. Seepage from the Fruitland coal outcrop in Colorado contributed at most 8\% of the total detected CH4, while gas venting from the San Juan underground coal mine contributed \<2\%.",
    url = "https://doi.org/10.1525/elementa.038",
    doi = "10.1525/elementa.038",
    openalex = "W3110437803",
    references = "doi1056577ffc2155"
}

Three new chasmosaurines from the Kirtland Formation (~75.0-73.4 Ma), New Mexico, form morphological and stratigraphic intermediates between Pentaceratops (~74.7-75 Ma, Fruitland Formation, New Mexico) and Anchiceratops (~72-71 Ma, Horseshoe Canyon Formation, Alberta). The new specimens exhibit gradual enclosure of the parietal embayment that characterizes Pentaceratops, providing support for the phylogenetic hypothesis that Pentaceratops and Anchiceratops are closely related. This stepwise change of morphologic characters observed in chasmosaurine taxa that do not overlap stratigraphically is supportive of evolution by anagenesis. Recently published hypotheses that place Pentaceratops and Anchiceratops into separate clades are not supported. This phylogenetic relationship demonstrates unrestricted movement of large-bodied taxa between hitherto purported northern and southern provinces in the late Campanian, weakening support for the hypothesis of extreme faunal provincialism in the Late Cretaceous Western Interior.

@article{doi107717peerj9251,
    author = "Fowler, Denver W. and Fowler, Elizabeth A. Freedman",
    title = "Transitional evolutionary forms in chasmosaurine ceratopsid dinosaurs: evidence from the Campanian of New Mexico",
    year = "2020",
    journal = "PeerJ",
    abstract = "Three new chasmosaurines from the Kirtland Formation (\textasciitilde 75.0-73.4 Ma), New Mexico, form morphological and stratigraphic intermediates between Pentaceratops (\textasciitilde 74.7-75 Ma, Fruitland Formation, New Mexico) and Anchiceratops (\textasciitilde 72-71 Ma, Horseshoe Canyon Formation, Alberta). The new specimens exhibit gradual enclosure of the parietal embayment that characterizes Pentaceratops, providing support for the phylogenetic hypothesis that Pentaceratops and Anchiceratops are closely related. This stepwise change of morphologic characters observed in chasmosaurine taxa that do not overlap stratigraphically is supportive of evolution by anagenesis. Recently published hypotheses that place Pentaceratops and Anchiceratops into separate clades are not supported. This phylogenetic relationship demonstrates unrestricted movement of large-bodied taxa between hitherto purported northern and southern provinces in the late Campanian, weakening support for the hypothesis of extreme faunal provincialism in the Late Cretaceous Western Interior.",
    url = "https://doi.org/10.7717/peerj.9251",
    doi = "10.7717/peerj.9251",
    openalex = "W3033842760",
    references = "doi101016jcretres2019104308, doi101098rsbl20140875, openalexw2772929664"
}

The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America's Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the 'zenith of dinosaur diversity'. The wide latitudinal distribution of rocks and fossils that represent this episode, spanning from northern Mexico to the northern slopes of Alaska, provides a unique opportunity to gain insights into dinosaur paleoecology and to address outstanding questions regarding faunal provinciality in connection to paleogeography and climate. Whereas reliable basin-wide correlations are fundamental to investigations of this sort, three decades of radioisotope geochronology of various vintages and limited compatibility has complicated correlation of distant fossil-bearing successions and given rise to contradictory paleobiogeographic and evolutionary hypotheses. Here we present new U-Pb geochronology by the CA-ID-TIMS method for 16 stratigraphically well constrained bentonite beds, ranging in age from 82.419 ± 0.074 Ma to 73.496 ± 0.039 Ma (2σ internal uncertainties), and the resulting Bayesian age models for six key fossil-bearing formations over a 1600 km latitudinal distance from northwest New Mexico, USA to southern Alberta, Canada. Our high-resolution chronostratigraphic framework for the upper Campanian of the Western Interior Basin reveals that despite their contrasting depositional settings and basin evolution histories, significant age overlap exists between the main fossil-bearing intervals of the Kaiparowits Formation (southern Utah), Judith River Formation (central Montana), Two Medicine Formation (western Montana) and Dinosaur Park Formation (southern Alberta). Pending more extensive paleontologic collecting that would allow more rigorous faunal analyses, our results support a first-order connection between paleoecologic and fossil diversities and help overcome the chronostratigraphic ambiguities that have impeded the testing of proposed models of latitudinal provinciality of dinosaur taxa during the Campanian.

@article{doi101038s4159802219896w,
    author = "Ramezani, Jahandar and Beveridge, Tegan L and Rogers, Raymond R and Eberth, David A and Roberts, Eric M",
    title = "Calibrating the zenith of dinosaur diversity in the Campanian of the Western Interior Basin by CA-ID-TIMS U-Pb geochronology.",
    year = "2022",
    journal = "Scientific reports",
    abstract = "The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America's Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the 'zenith of dinosaur diversity'. The wide latitudinal distribution of rocks and fossils that represent this episode, spanning from northern Mexico to the northern slopes of Alaska, provides a unique opportunity to gain insights into dinosaur paleoecology and to address outstanding questions regarding faunal provinciality in connection to paleogeography and climate. Whereas reliable basin-wide correlations are fundamental to investigations of this sort, three decades of radioisotope geochronology of various vintages and limited compatibility has complicated correlation of distant fossil-bearing successions and given rise to contradictory paleobiogeographic and evolutionary hypotheses. Here we present new U-Pb geochronology by the CA-ID-TIMS method for 16 stratigraphically well constrained bentonite beds, ranging in age from 82.419 ± 0.074 Ma to 73.496 ± 0.039 Ma (2σ internal uncertainties), and the resulting Bayesian age models for six key fossil-bearing formations over a 1600 km latitudinal distance from northwest New Mexico, USA to southern Alberta, Canada. Our high-resolution chronostratigraphic framework for the upper Campanian of the Western Interior Basin reveals that despite their contrasting depositional settings and basin evolution histories, significant age overlap exists between the main fossil-bearing intervals of the Kaiparowits Formation (southern Utah), Judith River Formation (central Montana), Two Medicine Formation (western Montana) and Dinosaur Park Formation (southern Alberta). Pending more extensive paleontologic collecting that would allow more rigorous faunal analyses, our results support a first-order connection between paleoecologic and fossil diversities and help overcome the chronostratigraphic ambiguities that have impeded the testing of proposed models of latitudinal provinciality of dinosaur taxa during the Campanian.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC9512893/",
    doi = "10.1038/s41598-022-19896-w",
    pmcid = "PMC9512893",
    pmid = "36163377"
}