Search

Your search keyword '"Green River Basin"' showing total 24 results
Start Over Descriptor "Green River Basin"
24 results on '"Green River Basin"'

1. Climate change and C4 and C3 grasses in a midlatitude dryland steppe.

Author

Anderson, Robert C., Martyn, Trace E., Renne, Rachel R., Burke, Ingrid C., and Lauenroth, William K.

Subjects
*CLIMATE change models, *CLIMATE change, *WATERSHEDS, *PLANT communities, *PLANT anatomy
Abstract

Climate change is projected to alter the structure of plant communities due to increasing temperatures and changes to precipitation patterns, particularly in midlatitude dryland ecosystems. Modifications to climatic suitability may lead to major community changes such as altered dominant plant functional types. Previous studies have indicated that climatic suitability is likely to increase for C4 grasses and decrease for C3 grasses in the Western United States. However, if no C4 grass species currently exist to serve as a propagule source, expansion into areas of increased suitability will be limited. We conducted a field and modeling study in the Upper Green River Basin (UGRB) of Western Wyoming to determine if (1) C4 grasses are present to provide a propagule source and (2) C4 grasses are likely to increase in importance relative to C3 grasses due to climatic changes. We searched 44 sites for C4 grasses to establish presence, and modeled suitability at 35 sites using 17 Global Climate Models, two greenhouse gas Representative Concentration Pathways (RCPs; 4.5 and 8.5), and two time periods (mid‐ and late century; 2030–2060 and 2070–2099, respectively). We found C4 grasses at 10 of the 44 sites, indicating that there is a present propagule source. Our model projected increases in suitability for both C3 and C4 grasses across sites for all RCPs and time periods. In the mid‐century RCP 4.5 scenario, the C3 functional type increased in projected biomass in 29 of 35 sites, and the C4 type increased in 31 sites. In this scenario, C3 grasses increased in projected biomass by a median 4 g m−2 (5% change), and C4 grass biomass increased by a median 8 g m−2 (21% change). Our study suggests that climate change will increase climatic suitability for grasses across the UGRB, and that all requirements are in place for C4 grasses to increase in abundance. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

2. Climate change and C4 and C3 grasses in a midlatitude dryland steppe

Author

Robert C. Anderson, Trace E. Martyn, Rachel R. Renne, Ingrid C. Burke, and William K. Lauenroth

Subjects
big sagebrush, climate change, functional types, Green River Basin, perennial grasses, Wyoming, Ecology, QH540-549.5
Abstract

Abstract Climate change is projected to alter the structure of plant communities due to increasing temperatures and changes to precipitation patterns, particularly in midlatitude dryland ecosystems. Modifications to climatic suitability may lead to major community changes such as altered dominant plant functional types. Previous studies have indicated that climatic suitability is likely to increase for C4 grasses and decrease for C3 grasses in the Western United States. However, if no C4 grass species currently exist to serve as a propagule source, expansion into areas of increased suitability will be limited. We conducted a field and modeling study in the Upper Green River Basin (UGRB) of Western Wyoming to determine if (1) C4 grasses are present to provide a propagule source and (2) C4 grasses are likely to increase in importance relative to C3 grasses due to climatic changes. We searched 44 sites for C4 grasses to establish presence, and modeled suitability at 35 sites using 17 Global Climate Models, two greenhouse gas Representative Concentration Pathways (RCPs; 4.5 and 8.5), and two time periods (mid‐ and late century; 2030–2060 and 2070–2099, respectively). We found C4 grasses at 10 of the 44 sites, indicating that there is a present propagule source. Our model projected increases in suitability for both C3 and C4 grasses across sites for all RCPs and time periods. In the mid‐century RCP 4.5 scenario, the C3 functional type increased in projected biomass in 29 of 35 sites, and the C4 type increased in 31 sites. In this scenario, C3 grasses increased in projected biomass by a median 4 g m−2 (5% change), and C4 grass biomass increased by a median 8 g m−2 (21% change). Our study suggests that climate change will increase climatic suitability for grasses across the UGRB, and that all requirements are in place for C4 grasses to increase in abundance.

Published
2024
Full Text
View/download PDF

3. Climate change and C 4 and C 3 grasses in a midlatitude dryland steppe.

Author

Anderson RC, Martyn TE, Renne RR, Burke IC, and Lauenroth WK

Abstract

Climate change is projected to alter the structure of plant communities due to increasing temperatures and changes to precipitation patterns, particularly in midlatitude dryland ecosystems. Modifications to climatic suitability may lead to major community changes such as altered dominant plant functional types. Previous studies have indicated that climatic suitability is likely to increase for C 4 grasses and decrease for C 3 grasses in the Western United States. However, if no C 4 grass species currently exist to serve as a propagule source, expansion into areas of increased suitability will be limited. We conducted a field and modeling study in the Upper Green River Basin (UGRB) of Western Wyoming to determine if (1) C 4 grasses are present to provide a propagule source and (2) C 4 grasses are likely to increase in importance relative to C 3 grasses due to climatic changes. We searched 44 sites for C 4 grasses to establish presence, and modeled suitability at 35 sites using 17 Global Climate Models, two greenhouse gas Representative Concentration Pathways (RCPs; 4.5 and 8.5), and two time periods (mid- and late century; 2030-2060 and 2070-2099, respectively). We found C 4 grasses at 10 of the 44 sites, indicating that there is a present propagule source. Our model projected increases in suitability for both C 3 and C 4 grasses across sites for all RCPs and time periods. In the mid-century RCP 4.5 scenario, the C 3 functional type increased in projected biomass in 29 of 35 sites, and the C 4 type increased in 31 sites. In this scenario, C 3 grasses increased in projected biomass by a median 4 g m -2 (5% change), and C 4 grass biomass increased by a median 8 g m -2 (21% change). Our study suggests that climate change will increase climatic suitability for grasses across the UGRB, and that all requirements are in place for C 4 grasses to increase in abundance., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Ecology and Evolution published by John Wiley & Sons Ltd.)

Published
2024
Full Text
View/download PDF

4. Mineralogy of Eocene Fossil Wood from the 'Blue Forest' Locality, Southwestern Wyoming, United States

Author

George E. Mustoe, Mike Viney, and Jim Mills

Subjects
Fossil wood, Blue Forest, Eden Valley, Lake Gosiute, chalcedony, quartz, calcite, stromatolite, Green River Basin, Wyoming, Geology, QE1-996.5
Abstract

Central Wyoming, USA, was the site of ancient Lake Gosiute during the Early Eocene. Lake Gosiute was a large body of water surrounded by subtropical forest, the lake being part of a lacustrine complex that occupied the Green River Basin. Lake level rises episodically drowned the adjacent forests, causing standing trees and fallen branches to become growth sites for algae and cyanobacteria, which encased submerged wood with thick calcareous stromatolitic coatings. The subsequent regression resulted in a desiccation of the wood, causing volume reduction, radial fractures, and localized decay. The subsequent burial of the wood in silty sediment led to a silicification of the cellular tissue. Later, chalcedony was deposited in larger spaces, as well as in the interstitial areas of the calcareous coatings. The final stage of mineralization was the precipitation of crystalline calcite in spaces that had previously remained unmineralized. The result of this multi-stage mineralization is fossil wood with striking beauty and a complex geologic origin.

Published
2019
Full Text
View/download PDF

5. A strategy for cross-calibrating U–Pb chronology and astrochronology of sedimentary sequences: An example from the Green River Formation, Wyoming, USA.

Author

Machlus, Malka L., Ramezani, Jahandar, Bowring, Samuel A., Hemming, Sidney R., Tsukui, Kaori, and Clyde, William C.

Subjects
*SEDIMENTARY basins, *ASTRONOMY, *CALIBRATION, *RADIOISOTOPES, *URANIUM, *LEAD
Abstract

Astronomical calibration of the geological timescale has been limited until recently by the precision and accuracy of radioisotopic dates, especially for pre-Neogene records. Uncertainties for radioisotopic dates of older strata were typically much larger than a single precessional cycle, and dates were often sparse, leading to the practice of orbital tuning of cyclic strata in order to astronomically calibrate the desired interval. Ideally, in order to test the assumptions of astronomical calibration with geochronology, it is necessary that the precision of radioisotopic dates be comparable to the period of the cycle being tested. The new U–Pb CA-TIMS (chemical abrasion–thermal ionization mass spectrometry) zircon dates reported here conform to this precision requirement, with 2 σ analytical uncertainties from ± 11 000 to ± 52 000 years for seven volcanic ashes from the Wilkins Peak Member of the Green River Formation. The zircon dates have simple distributions with few outliers and allow accurate estimations of the eruption ages with potential inaccuracies of less than precessional cycle. The Eocene Green River Formation (Wyoming, USA) has long been recognized as a record of cyclicly-deposited lacustrine sediments, and the abundant intercalated volcanic ashes make it a suitable place to test new approaches to astronomical calibration of cyclic strata. The abundance of different types of marker beds, including tuffs that are intercalated with the sedimentary cycles, guarantee an unambiguous correlation between sampling locations of dated tuffs on the margins of the basin and the basin center where the cyclicity is best developed, thus reducing any stratigraphic uncertainties to a fraction of (hypothesized) precession cycle. Tuning-based orbital age models, accepted by the previous geochronology, significantly deviate from the new geochronology, whereas a previously rejected model that assumes a short eccentricity period of 125 ky is now allowed. In order to test possible explanations for the apparent 125 ky period, such as changes in orbital periods, or gaps in the sedimentary record, we present an iterative strategy to select future ashes for dating such that the astronomical calibration/testing is optimized. We iteratively contrast two ad-hoc age models that bracket the linear interpolation between the dated ashes. The optimal intervals for further dating are located where the deviations between the models exceed our reported uncertainties. We propose that the iterative approach described here should become the standard for establishing a rigorous orbital calibration of the stratigraphic record where sufficient ashes exist. [ABSTRACT FROM AUTHOR]

Published
2015
Full Text
View/download PDF

6. Coupled CO2-climate response during the Early Eocene Climatic Optimum

Author

Hyland, Ethan G. and Sheldon, Nathan D.

Subjects
*EOCENE paleoclimatology, *CLIMATE change, *METEOROLOGICAL precipitation, *GEOCHEMISTRY, *ISOTOPE geology, *ATMOSPHERIC temperature, *ALFISOLS, *WATERSHEDS
Abstract

Abstract: The Early Eocene Climatic Optimum (EECO) has been characterized as a prolonged warm event indicated by increased atmospheric pCO2, temperatures, precipitation, and biological turnover. A new paleoenvironmental reconstruction using integrated pedological, geochemical, and isotopic data from the Green River Basin (Green River/Great Divide region) provides a high-resolution record of environmental and climatic change throughout the EECO. Our reconstruction indicates that this region, and likely much of the margin of paleolake Gosiute, was a stable, fluvially-controlled floodplain environment with evidence of large scale continuous soil development and features comparable with modern Alfisols (temperate forest soils). Regional climate data from multiple proxies indicates that the period was warm-temperate and semi-arid to sub-humid, with a peak interval from about 51.5–50.9Ma that exhibits significantly warmer (~7°C) and wetter (~750mmyr−1) conditions, resulting in major changes to the local weathering regime. Isotopic analyses also indicate a rapid increase to high atmospheric pCO2 values (~1700ppmV) and a shift in the δ13C composition of pedogenic carbonates during this peak interval that appear to define and provide a cause for this significant regional response to global climatic change. The new data, when combined with foraminiferal δ13C records, are consistent with CO2 ventilation from a deep marine reservoir source. This multi-proxy reconstruction suggests that the EECO may have had a superimposed “peak” of climatic and ecological change on land. [Copyright &y& Elsevier]

Published
2013
Full Text
View/download PDF

7. Pictures by the Seedskadee: A Preliminary Analysis of the Biographic Rock Art of the Green River Basin, Southwestern, Wyoming.

Author

Keyser, James D., Tanner, Russel L., and Vlcek, David T.

Subjects
*ROCK paintings, *PETROGLYPHS, *PICTURE-writing, *PRIMITIVE art, *PREHISTORIC art
Abstract

The Green River Basin of southwestern Wyoming has only recently been recognized as containing a rich rock art record closely related to Plains styles and traditions. Preliminary recording in 2002 shows that Biographic rock art is a major component at six Green River Basin sites. The Biographic petroglyphs there represent four different styles that relate to both Northern Plains and Colorado Plateau rock art, reflecting the importance of the Green River as a traders' rendezvous and travel route throughout the Historic period. An extensive Biographic composition at the La Barge Bluffs site is the finest realistic composition currently known in Plains rock art. [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

8. Tectonic and paleogeographic implications of late Laramide geologic history in the northeastern corner of Wyoming's Hanna Basin.

Author

Lillegraven, Jason A., Snoke, Arthur W., and McKenna, Malcolm C.

Subjects
OROGENY, PALEOBOTANY, PALEOCENE stratigraphic geology, STRUCTURAL geology
Abstract

The Hanna Basin of south-central Wyoming has been considered anomalous among other Laramide depocenters of the Rocky Mountain region because of its combination of small size and great thickness of synorogenic strata. Most prior interpretations of the Hanna Basin have assumed a history of subsidence and sedimentary infilling discrete from surrounding basins. In contrast, we summarize new geological and paleontological information from the northeastern corner of the modern Hanna Basin suggesting that, prior to late Paleocene time, the Hanna Basin and nearby Carbon, Pass Creek, Laramie, and Shirley Basins were unified and depositionally continuous with the much larger Green River Basin to the west. Only late in the local expression of the Laramide orogeny (late Paleocene and early Eocene) did this "greater Green River Basin" become subdivided through completion of development of intrabasinal, basement-involved thrust faulting and associated anticlines. We view the present Hanna Basin as only a small, structurally defined remnant of an enormous, ponded basin that extended eastward during most of Paleocene time from the Wyoming-Idaho-Utah thrust belt to the newly uplifted Laramie Mountains. That basin was bounded on the south by the Uinta Mountains and combined Sierra Madre-Medicine Bow Mountains and on the north by the Gros Ventre Range, Wind River Mountains, and Sweetwater arch. When the original configuration of the unified greater Green River Basin is taken into account and combined with palinspastic removal of late Laramide faulting that defines its various margins, this basin at least rivaled dimensions of the Powder River Basin of Wyoming and Montana; the greater Green River Basin greatly exceeded the volume of sedimentary accumulation within the Powder River Basin. Rates of Paleogene basinal erosion associated with structural subdivision of eastern components of the greater Green River Basin were prodigious. Within context of a measured... [ABSTRACT FROM AUTHOR]

Published
2004
Full Text
View/download PDF

9. Mineralogy of Eocene Fossil Wood from the 'Blue Forest' Locality, Southwestern Wyoming, United States

Author

Jim Mills, Mike Viney, and George E. Mustoe

Subjects
Wyoming, chalcedony, 010504 meteorology & atmospheric sciences, Chalcedony, Geochemistry, Drainage basin, Fossil wood, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, chemistry.chemical_compound, Algae, Eden Valley, stromatolite, Tropical and subtropical moist broadleaf forests, 0105 earth and related environmental sciences, Calcite, geography, geography.geographical_feature_category, biology, Ancient lake, lcsh:QE1-996.5, Blue Forest, biology.organism_classification, quartz, lcsh:Geology, Stromatolite, chemistry, engineering, General Earth and Planetary Sciences, Green River Basin, Lake Gosiute, calcite, Geology
Abstract

Central Wyoming, USA, was the site of ancient Lake Gosiute during the Early Eocene. Lake Gosiute was a large body of water surrounded by subtropical forest, the lake being part of a lacustrine complex that occupied the Green River Basin. Lake level rises episodically drowned the adjacent forests, causing standing trees and fallen branches to become growth sites for algae and cyanobacteria, which encased submerged wood with thick calcareous stromatolitic coatings. The subsequent regression resulted in a desiccation of the wood, causing volume reduction, radial fractures, and localized decay. The subsequent burial of the wood in silty sediment led to a silicification of the cellular tissue. Later, chalcedony was deposited in larger spaces, as well as in the interstitial areas of the calcareous coatings. The final stage of mineralization was the precipitation of crystalline calcite in spaces that had previously remained unmineralized. The result of this multi-stage mineralization is fossil wood with striking beauty and a complex geologic origin.

Published
2019

10. PECKED PETROGLYPHS AT THE GATEWAY SITE: THE UNCOMPAHGRE STYLE IN THE GREEN RIVER BASIN

Author

Keyser, James D., Fossati, Angelo Eugenio, Fossati, Angelo Eugenio (ORCID:0000-0003-4229-9488), Keyser, James D., Fossati, Angelo Eugenio, and Fossati, Angelo Eugenio (ORCID:0000-0003-4229-9488)

Abstract

The paper deals with the discovery of the UNCOMPAHGRE STYLE on a rockat Gateway site, in the Green River Basin (USA)

Published
2016

11. Mineralogy of Eocene Fossil Wood from the "Blue Forest" Locality, Southwestern Wyoming, United States.

Author

Mustoe, George E., Viney, Mike, and Mills, Jim

Subjects
BODIES of water, FOSSIL trees, MINERALOGY
Abstract

Central Wyoming, USA, was the site of ancient Lake Gosiute during the Early Eocene. Lake Gosiute was a large body of water surrounded by subtropical forest, the lake being part of a lacustrine complex that occupied the Green River Basin. Lake level rises episodically drowned the adjacent forests, causing standing trees and fallen branches to become growth sites for algae and cyanobacteria, which encased submerged wood with thick calcareous stromatolitic coatings. The subsequent regression resulted in a desiccation of the wood, causing volume reduction, radial fractures, and localized decay. The subsequent burial of the wood in silty sediment led to a silicification of the cellular tissue. Later, chalcedony was deposited in larger spaces, as well as in the interstitial areas of the calcareous coatings. The final stage of mineralization was the precipitation of crystalline calcite in spaces that had previously remained unmineralized. The result of this multi-stage mineralization is fossil wood with striking beauty and a complex geologic origin. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

12. Soda ash's Indian summer.

Author

O'Driscoll M. and O'Driscoll M.

Abstract

Market demand is outstripping supply for soda ash, particularly in Asia, and there has been significant acquisition and expansion activity. Indian companies have acquired significant sources in Europe, Africa and more recently in the USA. Methods for producing soda ash are described and applications discussed, including flat and container glass, soaps and detergents, chemicals, pulp and paper and metals and mining. Details are given of the major producers, location and soda ash source (trona, lake brines and synthetic). Operations are described at the Green River Basin trona deposits in Wyoming, and details given of a 1 000 000 tpa synthetic soda ash project being developed in Saudi Arabia., Market demand is outstripping supply for soda ash, particularly in Asia, and there has been significant acquisition and expansion activity. Indian companies have acquired significant sources in Europe, Africa and more recently in the USA. Methods for producing soda ash are described and applications discussed, including flat and container glass, soaps and detergents, chemicals, pulp and paper and metals and mining. Details are given of the major producers, location and soda ash source (trona, lake brines and synthetic). Operations are described at the Green River Basin trona deposits in Wyoming, and details given of a 1 000 000 tpa synthetic soda ash project being developed in Saudi Arabia.

Published
2008

13. Development of a methodology for analysis of instability in room and pillar mines.

Author

Board M., Deep mining 07, Perth, Australia, 7-9 Nov. 2007, Damjanac B., Pierce M., Board M., Deep mining 07, Perth, Australia, 7-9 Nov. 2007, Damjanac B., and Pierce M.

Abstract

A number of major roof falls and panel collapses have occurred since 1994 in room and pillar trona mines n the Green River Basin of Wyoming, USA. A method is described for estimating the potential for major panel collapses which was developed through back-analysis of several collapse incidents. The method involves separate analysis of the stress-strain response of the primary mechanical components of the system, the pillar/floor system for a particular pillar design and extraction ratio, and the overlying roof strata for given panel widths and barrier pillar dimensions. The stress-strain response of the pillar/floor system is estimated through back analysis of instrumented case studies and observations of pillar/floor punching. The stiffness and yield response of the overburden is estimated numerically by replacing the panel pillars with an equivalent backpressure, and then incrementally removing the pressure to allow closure of the seam. The pressure-displacement response of the two components are superimposed to determine whether an equilibrium state can be achieved, and to estimate the potential violence of the failure response if equilibrium cannot be achieved. A case study is presented for the collapse of three panels at a particular mine., A number of major roof falls and panel collapses have occurred since 1994 in room and pillar trona mines n the Green River Basin of Wyoming, USA. A method is described for estimating the potential for major panel collapses which was developed through back-analysis of several collapse incidents. The method involves separate analysis of the stress-strain response of the primary mechanical components of the system, the pillar/floor system for a particular pillar design and extraction ratio, and the overlying roof strata for given panel widths and barrier pillar dimensions. The stress-strain response of the pillar/floor system is estimated through back analysis of instrumented case studies and observations of pillar/floor punching. The stiffness and yield response of the overburden is estimated numerically by replacing the panel pillars with an equivalent backpressure, and then incrementally removing the pressure to allow closure of the seam. The pressure-displacement response of the two components are superimposed to determine whether an equilibrium state can be achieved, and to estimate the potential violence of the failure response if equilibrium cannot be achieved. A case study is presented for the collapse of three panels at a particular mine.

Published
2007

14. Adsorption of carbonate and bicarbonate salts at the air-brine interface.

Author

Ozdemir O., Karakashev S.I., Miller J.D., Nguyen A.V., Ozdemir O., Karakashev S.I., Miller J.D., and Nguyen A.V.

Abstract

The flotation of soluble salt is discussed, with particular reference to carbonate salts such as those associated with the trona deposit of the Green River basin, Wyoming. The equilibrium and dynamic surface tensions of sodium carbonate and sodium bicarbonate salts were measured as a function of the salt concentration up to saturation and compared with model predictions using the Gibbs-Langmuir adsorption theory. The results showed that negative adsorption of sodium carbonate leads to a significant increase in surface tension of the brine solution. The negative adsorption and the increase in surface tension are significantly lower for sodium bicarbonate compared with sodium carbonate. Sodium ions are significantly more hydrated than carbonate and bicarbonate ions, and tend to be excluded from the air-brine interface while carbonate and bicarbonate ions are accommodated at the interface. The balance between sodium exclusion and carbonate/bicarbonate accommodation results in an increase in the surface tension of these solutions, with an increase in salt concentration., The flotation of soluble salt is discussed, with particular reference to carbonate salts such as those associated with the trona deposit of the Green River basin, Wyoming. The equilibrium and dynamic surface tensions of sodium carbonate and sodium bicarbonate salts were measured as a function of the salt concentration up to saturation and compared with model predictions using the Gibbs-Langmuir adsorption theory. The results showed that negative adsorption of sodium carbonate leads to a significant increase in surface tension of the brine solution. The negative adsorption and the increase in surface tension are significantly lower for sodium bicarbonate compared with sodium carbonate. Sodium ions are significantly more hydrated than carbonate and bicarbonate ions, and tend to be excluded from the air-brine interface while carbonate and bicarbonate ions are accommodated at the interface. The balance between sodium exclusion and carbonate/bicarbonate accommodation results in an increase in the surface tension of these solutions, with an increase in salt concentration.

Published
2006

15. Integrated design of tailings basin seepage control systems using analytic element ground-water models.

Author

Wuolo R.W., Tailings and Mine Waste '95 Fort Collins, Colorado 17-Jan-9520-Jan-95, Wuolo R.W., and Tailings and Mine Waste '95 Fort Collins, Colorado 17-Jan-9520-Jan-95

Abstract

An AEM (analytic element method) model has been developed for the Rhone-Poulenc trona facility in Green River, Wyoming - an area which includes several tailings basins, the Green River, fractured rock, meander-belt alluvium, and a number of existing remediation systems. The model was calibrated to observed hydraulic head conditions and then used to design a comprehensive seepage interception system that can be integrated with the existing systems. The lack of a grid mesh in the model allows for the detailed examination of flow near the tailings basins and remediation systems, while still taking account of the overall groundwater flow for the whole area., An AEM (analytic element method) model has been developed for the Rhone-Poulenc trona facility in Green River, Wyoming - an area which includes several tailings basins, the Green River, fractured rock, meander-belt alluvium, and a number of existing remediation systems. The model was calibrated to observed hydraulic head conditions and then used to design a comprehensive seepage interception system that can be integrated with the existing systems. The lack of a grid mesh in the model allows for the detailed examination of flow near the tailings basins and remediation systems, while still taking account of the overall groundwater flow for the whole area.

Published
1995

16. A new Early Eocene (Lostcabinian) mammal assemblage from the Main Body of the Wasatch Formation, Northern Green River Basin; The Pinnacles, Sweetwater Co., Wyoming

Author

Neumann, Allison Marie

Subjects
Green River Basin, Lostcabinian, Eocene
Abstract

Abstract: Taphonomy of fluvially deposited microvertebrates and systematic paleontology of the Pinnacles buttes in the northwest Great Divide Basin is examined. The Pinnacles buttes contain an early Eocene mammal assemblage of over 900 cataloged specimens from several prolific University of Michigan localities. The diverse assemblage is represented by a minimum of 56 species of 30 families. Sedimentology of the Main Body of the Wasatch formation in the basin margin of the Great Divide has not previously been examined. This thesis provides the first detailed descriptions and measurements of these specimens and explores the sedimentological and taphonomical environments in which this diverse assemblage accumulated in. The microvertebrate fossils were collected from chute-modified channel bar deposits at two fossiliforous horizons in the uppermost 40-50 m of the Main Body of the Wasatch Formation. Concentration of fossils to discrete horizons vertically associated with crevasse splays and gravel bed streams suggests that proximal channel facies played a pivotal role in preservation of fossils in this setting.

Published
2013

17. The sedimentology and stratigraphic architecture of the Cathedral Bluffs Tongue of the Wasatch Formation, South Pass, Wyoming

Author

McHugh, Luke P

Subjects
Whole-rock geochemistry, Wasatch Formation, Outcrop gamma, Fluvial, Sequence stratigraphy, Lacustrine, Green River Basin, Cathedral Bluffs Tongue, Sedimentology, South Pass, Chemostratigraphy
Abstract

Abstract: The early Eocene (Gardnerbuttean) Cathedral Bluffs Tongue of the Wasatch Formation near South Pass, Wyoming preserves a succession of continental fluvial deposits, which interfinger with lacustrine strata of the Green River Formation in a basinward direction. This thesis focuses on the sedimentology of the Cathedral Bluffs Tongue and identifies the dominant influences on sediment accumulation. Previous studies focused primarily on the regional (basin-scale) lithostratigraphic architecture of Eocene strata in the Green River Basin. Detailed sedimentological analyses of the study interval have not previously been completed. Using whole-rock geochemistry, gamma spectrometry, outcrop description and petrography, fine-scale correlations were made through the study interval. As climate remained constant throughout the ~ 1. 5 million year study interval, and syndepositional structural influences can be demonstrated in the study area, it is shown that movement of the Wind River Thrust Fault, played a dominant role in Early Eocene sediment accumulation at South Pass.

Published
2012

18. An Analysis of the Source Rock-Transport-Sediment System Using Multivariate Statistical Procedures.

Author

WYOMING UNIV LARAMIE, Steidtmann,James R., WYOMING UNIV LARAMIE, and Steidtmann,James R.

Abstract

Analysis of 1500 samples of modern stream and lake sediment and source rock reveals some of the factors that control downstream changes in the heavy mineralogy of sediments in a degrading stream. Factor and vector analysis and other multivariate methods were used to identify sources of variation, between sample similarity, and interdependent variables. This study focuses on the general source-sediment relations. The purpose of this study is to evaluate these relations in a Holocene setting where the heavy mineralogy of both source rocks and stream sediments can be determined and to develop specific multivariate statistical techniques which are necessary to elucidate these relations. In particular, this study is aimed at determining the importance of (1) distant and local sources, (2) dilution by bank cutting, (3) mixing at stream confluences, (4) sediment entrapment in lakes, (5) specific source characteristics such as drainage controls and concentrations of heavy minerals and, (6) stream size.

Published
1976

19. A field study of longwall mine ventilation using tracer gas in a trona mine.

Author

Gangrade V., Harteis S.P., Schatzel S.J., Gangrade V., Harteis S.P., and Schatzel S.J.

Abstract

A ventilation research study was conducted by the National Institute for Occupational Safety and Health and a cooperating trona mine in the Green River basin of Wyoming, USA. The mine operation uses the longwall mining method in trona bed 17, a commonly mined unit in the region. The longwall face length is 228 m (750 ft), and caving on the face occurred up to the back of the longwall shields. The mine is ventilated using a main blowing fan and a bleeder shaft. For this study, sulphur hexafluoride (SF6) tracer gas was released in two separate monitoring experiments. For the first experiment, tracer gas was released on the face, this test focused on airflow along the longwall face of the active panel. Face test showed the airflow patterns to be more complex than just head-to-tail flow in the main ventilation air stream on the active panel. For the second experiment, tracer gas was released 2 crosscuts in by the face on the headgate side, this test focused on gas transport in the mined-out portion of the same active panel. Gob test showed a pathway of movement through the front of the active panel gob that moved outby from the tailgate corner. The primary pathway of tracer gas movement in the active panel gob was towards the headgate and tailgate bleeders and out of a bleeder shaft. The rate of movement towards the back of the gob was measured to be 0.19 m/s (37 fpm). (Authors.), A ventilation research study was conducted by the National Institute for Occupational Safety and Health and a cooperating trona mine in the Green River basin of Wyoming, USA. The mine operation uses the longwall mining method in trona bed 17, a commonly mined unit in the region. The longwall face length is 228 m (750 ft), and caving on the face occurred up to the back of the longwall shields. The mine is ventilated using a main blowing fan and a bleeder shaft. For this study, sulphur hexafluoride (SF6) tracer gas was released in two separate monitoring experiments. For the first experiment, tracer gas was released on the face, this test focused on airflow along the longwall face of the active panel. Face test showed the airflow patterns to be more complex than just head-to-tail flow in the main ventilation air stream on the active panel. For the second experiment, tracer gas was released 2 crosscuts in by the face on the headgate side, this test focused on gas transport in the mined-out portion of the same active panel. Gob test showed a pathway of movement through the front of the active panel gob that moved outby from the tailgate corner. The primary pathway of tracer gas movement in the active panel gob was towards the headgate and tailgate bleeders and out of a bleeder shaft. The rate of movement towards the back of the gob was measured to be 0.19 m/s (37 fpm). (Authors.)

20. Solution mining of trona.

Author

Haynes H.W. and Haynes H.W.

Abstract

Two approaches to solution mining are currently being pursued. The first consists of two or more wells drilled into the trona bed and a low-pressure connection established by hydraulic fracturing or directional drilling. Solution is injected into one well and product brine is collected from one or more production wells. The second type involves the flooding of a previouly-mined region to create an underground lake. Disolution of trona occurs and the brine is pumped to the surface for processing. Several of the first type of mine have been tested extensively and at least three of the second type are currently operating in the Green River Basin in Wyoming. Dissolution rates can be enhanced by operation at elevated temperatures or by adding chemical reagents to prevent precipitation of bicarbonate. Discussion is presented of the thermodynamics of dissolution and crystallisation., Two approaches to solution mining are currently being pursued. The first consists of two or more wells drilled into the trona bed and a low-pressure connection established by hydraulic fracturing or directional drilling. Solution is injected into one well and product brine is collected from one or more production wells. The second type involves the flooding of a previouly-mined region to create an underground lake. Disolution of trona occurs and the brine is pumped to the surface for processing. Several of the first type of mine have been tested extensively and at least three of the second type are currently operating in the Green River Basin in Wyoming. Dissolution rates can be enhanced by operation at elevated temperatures or by adding chemical reagents to prevent precipitation of bicarbonate. Discussion is presented of the thermodynamics of dissolution and crystallisation.

21. Shortwall mining of trona.

Author

Harris R.A., Mining technology and policy issues International mining show, Las Vegas, Nevada, 5-9 October 19861986, Harris R.A., and Mining technology and policy issues International mining show, Las Vegas, Nevada, 5-9 October 19861986

22. Detrital mantle indicator minerals in southwestern Wyoming, USA: evaluation of mantle environment, igneous host and diamond exploration significance.

Author

McCandless T.E., Nash W.P., McCandless T.E., and Nash W.P.

Abstract

Detrital mantle-derived minerals found in secondary environments in the Green River Basin and the Uinta Mountains are similar to minerals comprising perodotite and eclogite. However, diagnostic diamond indicators are absent. P-T estimates from inclusions in the detrital minerals suggest that they originally formed in the upper mantle under oxidising, volatile-rich conditions at 620-820 degrees C for an assumed pressure range of 10-30 kb, outside the conditions of formation for diamond. The detrital minerals comprise part of the indicator mineral suite that is used worldwide in kimberlite and lamproite exploration. A similar igneous host is envisioned based on the occurrence of lamproite and peridotite in the region. Dark green, high-Fe salitic diopsides are restricted in occurrence to the Hatcher Mesa lamproite in the Leucite Hills and the antmounds in the Green River Basin, and may represent a new indicator mineral that can be used in exploration for lamproites. The primary source of these mantle-derived indicator minerals is unknown, but is believed to be kimberlite or lamproite located in the southern Green River Basin and northeastern Uinta Mountains., Detrital mantle-derived minerals found in secondary environments in the Green River Basin and the Uinta Mountains are similar to minerals comprising perodotite and eclogite. However, diagnostic diamond indicators are absent. P-T estimates from inclusions in the detrital minerals suggest that they originally formed in the upper mantle under oxidising, volatile-rich conditions at 620-820 degrees C for an assumed pressure range of 10-30 kb, outside the conditions of formation for diamond. The detrital minerals comprise part of the indicator mineral suite that is used worldwide in kimberlite and lamproite exploration. A similar igneous host is envisioned based on the occurrence of lamproite and peridotite in the region. Dark green, high-Fe salitic diopsides are restricted in occurrence to the Hatcher Mesa lamproite in the Leucite Hills and the antmounds in the Green River Basin, and may represent a new indicator mineral that can be used in exploration for lamproites. The primary source of these mantle-derived indicator minerals is unknown, but is believed to be kimberlite or lamproite located in the southern Green River Basin and northeastern Uinta Mountains.

23. Trona resources in the Green River Basin, southwest Wyoming.

Author

Dyni J.R., Grundy W.D., Wiig S.V., Dyni J.R., Grundy W.D., and Wiig S.V.

Abstract

The lacustrine Green River Formation of Eocene age in the Green River Basin, SW Wyoming, contains the world's largest resource of natural sodium carbonate in bedded trona (Na2CO3.NaHCO3.2H2O). In this study 126 billion tons are estimated to be present in 22 beds, ranging from 4 to 36 ft in thickness. These 22 beds underlie areas of about 50 to more than 775 square miles at depths ranging from 650 to more than 3 000 ft below the surface. The total resource of trona ore in the Basin, for which drilling information is available, is estimated to be about 149 billion short tons. The undeveloped deeper trona beds on the southern part of the Basin may be exploitable by solution mining. Additional unevaluated sodium carbonate resources are present in disseminated shortite in strata interbedded with the trona and in shallow sodium carbonate brines in the NE part of the Basin., The lacustrine Green River Formation of Eocene age in the Green River Basin, SW Wyoming, contains the world's largest resource of natural sodium carbonate in bedded trona (Na2CO3.NaHCO3.2H2O). In this study 126 billion tons are estimated to be present in 22 beds, ranging from 4 to 36 ft in thickness. These 22 beds underlie areas of about 50 to more than 775 square miles at depths ranging from 650 to more than 3 000 ft below the surface. The total resource of trona ore in the Basin, for which drilling information is available, is estimated to be about 149 billion short tons. The undeveloped deeper trona beds on the southern part of the Basin may be exploitable by solution mining. Additional unevaluated sodium carbonate resources are present in disseminated shortite in strata interbedded with the trona and in shallow sodium carbonate brines in the NE part of the Basin.

Catalog

Books, media, physical & digital resources
See catalog results