Pub Date : 1986-10-01DOI: 10.31582/rmag.mg.23.4.107
L. K. Barlow
A detailed study of paleoecological, geochemical, and stable isotopic properties of the lower Niobrara Formation (upper Turonian to lower Coniacian) was undertaken in order to evaluate petroleum source rock potential and to gain an understanding of the processes affecting variation in organic carbon content. The highest organic carbon contents In the lower Niobrara Formation occur in the lower shale unit of the Smoky Hill Shale Membel Trends in extent of bioturbation, organic carbon contents, and oxygen isotopic ratios of carbonates suggest that paleoclimatic factors influenced bottom water environments during deposition of this unit. A shift toward a more negative oxygen isotopic ratio in the lower shale unit is interpreted to be a result of decreased surface water salinity due to increased fresh water input and possibly to climatic warming. Resultant stratification of the water column limited benthic oxygenation thereby limiting benthic activity, enhancing the preservation of marine organic matter, and increasing source rock potential for petroleum. Data from underlying and overlying units in the lower Niobrara Formation suggest more normal marine conditions with well-oxygenated bottom waters, normal levels of bioturbation, and relatively low organic carbon contents. Pyrolysis data are interpreted to reflect a principally marine source of organic matter with substantial alteration due to bioturbation and thermal evolution. Elevated thermal maturity of the section at Lyons is inferred to be a local feature caused by local heating associated with fluid movement along fault zones or with emplacement of Tertiary sills.
{"title":"An Integrated Geochemical and Paleoecological Approach to Petroleum Source Rock Evaluation, Lower Niobrara Formation (Cretaceous), Lyons, Colorado","authors":"L. K. Barlow","doi":"10.31582/rmag.mg.23.4.107","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.4.107","url":null,"abstract":"A detailed study of paleoecological, geochemical, and stable isotopic properties of the lower Niobrara Formation (upper Turonian to lower Coniacian) was undertaken in order to evaluate petroleum source rock potential and to gain an understanding of the processes affecting variation in organic carbon content. The highest organic carbon contents In the lower Niobrara Formation occur in the lower shale unit of the Smoky Hill Shale Membel Trends in extent of bioturbation, organic carbon contents, and oxygen isotopic ratios of carbonates suggest that paleoclimatic factors influenced bottom water environments during deposition of this unit. A shift toward a more negative oxygen isotopic ratio in the lower shale unit is interpreted to be a result of decreased surface water salinity due to increased fresh water input and possibly to climatic warming. Resultant stratification of the water column limited benthic oxygenation thereby limiting benthic activity, enhancing the preservation of marine organic matter, and increasing source rock potential for petroleum. Data from underlying and overlying units in the lower Niobrara Formation suggest more normal marine conditions with well-oxygenated bottom waters, normal levels of bioturbation, and relatively low organic carbon contents. Pyrolysis data are interpreted to reflect a principally marine source of organic matter with substantial alteration due to bioturbation and thermal evolution. Elevated thermal maturity of the section at Lyons is inferred to be a local feature caused by local heating associated with fluid movement along fault zones or with emplacement of Tertiary sills.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131334485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-10-01DOI: 10.31582/rmag.mg.23.4.128
I. S. Merin, R. C. Lindholm
Sandstones in the upper part of the Paleocene Tongue River Member of the Fort Union Formation in the Powder River basin are dominantly sublitharenite. These rocks contain abundant rock fragments of non-ferroan calcite, dolomite, chert, and foliated tine-grained metamorphic rock (phyllite). The carbonate and chert rock fragments were probably eroded from Paleozoic carbonate sequences flanking the Bighorn Mountains or the Black Hills. The phyllffic rock fragments indicate that the crystalline cores of these uplifts were exposed during Paleocene time, which is earlier during the Laramide Orogeny than has been previously demonstrated.
{"title":"Evidence that the Crystalline Cores of Uplifts Adjacent to the Powder River Basin Were Breached During Paleocene Time","authors":"I. S. Merin, R. C. Lindholm","doi":"10.31582/rmag.mg.23.4.128","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.4.128","url":null,"abstract":"Sandstones in the upper part of the Paleocene Tongue River Member of the Fort Union Formation in the Powder River basin are dominantly sublitharenite. These rocks contain abundant rock fragments of non-ferroan calcite, dolomite, chert, and foliated tine-grained metamorphic rock (phyllite). The carbonate and chert rock fragments were probably eroded from Paleozoic carbonate sequences flanking the Bighorn Mountains or the Black Hills. The phyllffic rock fragments indicate that the crystalline cores of these uplifts were exposed during Paleocene time, which is earlier during the Laramide Orogeny than has been previously demonstrated.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128269399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-07-01DOI: 10.31582/rmag.mg.23.3.95
W. Gates, P. H. Rahn
Large orthoquartzite boulders mantle parts of the Red valley, the lowland underlain by the Spearfish Formation which separates the Black Hills from the Cretaceous hogback. The boulders are concentrated near the top of small hills where they retard the erosion of the underlying shale. The boulders are believed to represent relict positions of outcrops of the Lakota Formation, and to have been let down as much as 300m in elevation during the later part of the Cenozoic era.
{"title":"Ancient Quartzite Boulders in the Red Valley Area of the Northern Black Hills, South Dakota and Wyoming","authors":"W. Gates, P. H. Rahn","doi":"10.31582/rmag.mg.23.3.95","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.3.95","url":null,"abstract":"Large orthoquartzite boulders mantle parts of the Red valley, the lowland underlain by the Spearfish Formation which separates the Black Hills from the Cretaceous hogback. The boulders are concentrated near the top of small hills where they retard the erosion of the underlying shale. The boulders are believed to represent relict positions of outcrops of the Lakota Formation, and to have been let down as much as 300m in elevation during the later part of the Cenozoic era.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123808506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-07-01DOI: 10.31582/rmag.mg.23.3.77
Ivan D. Sanderson, Michael T. Wiley
The Jesse Ewing Canyon Formation, a member of the Middle Proterozic Uinta Mountain Group, is here proposed as a formal lithostratigraphic unit. It consists of interbedded dark reddish-brown to dark gray conglomerate with predominant white, pale green, gray, or pink metaquartzite clasts, light to dark brown or reddish-brown quartz arenite, and reddish-brown, red, or maroon shale. This represents the first proposal of a formation in the Uinta Mountain Group in the eastern part of the range and follows by only a few years beginning efforts to establish formations in the group in the western part. The Jesse Ewing Canyon Formation locally constitutes the basal member of the Uinta Mountain Group and is here reaffirmed as an alluvial fan deposit, based on a detailed comparison of observed features to those of modern alluvial fans. This interpretation supports the hypothesis that the Uinta Trough is an aulacogen.
{"title":"The Jesse Ewing Canyon Formation, an Interpreted Alluvial Fan Deposit in the Basal Uinta Mountain Group (Middle Proterozoic), Utah","authors":"Ivan D. Sanderson, Michael T. Wiley","doi":"10.31582/rmag.mg.23.3.77","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.3.77","url":null,"abstract":"The Jesse Ewing Canyon Formation, a member of the Middle Proterozic Uinta Mountain Group, is here proposed as a formal lithostratigraphic unit. It consists of interbedded dark reddish-brown to dark gray conglomerate with predominant white, pale green, gray, or pink metaquartzite clasts, light to dark brown or reddish-brown quartz arenite, and reddish-brown, red, or maroon shale. This represents the first proposal of a formation in the Uinta Mountain Group in the eastern part of the range and follows by only a few years beginning efforts to establish formations in the group in the western part. The Jesse Ewing Canyon Formation locally constitutes the basal member of the Uinta Mountain Group and is here reaffirmed as an alluvial fan deposit, based on a detailed comparison of observed features to those of modern alluvial fans. This interpretation supports the hypothesis that the Uinta Trough is an aulacogen.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126758344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-07-01DOI: 10.31582/rmag.mg.23.3.90
L. Woodward
{"title":"Discussion: A Case for Brittle Deformation of the Basement During the Laramide Revolution in the Rocky Mountain Foreland Province","authors":"L. Woodward","doi":"10.31582/rmag.mg.23.3.90","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.3.90","url":null,"abstract":"","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130661617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-04-01DOI: 10.31582/rmag.mg.23.2.63
M. Kirschbaum
A record at an ancient delta system Is preserved in outcrops along the flanks of the Rock Springs Uplift, southwestern Wyoming. The deltaic Upper Cretaceous Rock Springs Formation of the Mesaverde Group was deposited during early Campanian time near the end of the regressive phase of the Niobrara cyclothem. On the southwest end of the Uplift, part of the delta system is exposed near the seaward edge of a series of transgressive/regressive sequences, which consist of intertonguing prodelta, delta-front, and delta-plain deposits. Eight major delta-front sandstones are vertically stacked and laterally continuous throughout the main study area, intertonguing with prodefta deposits of the Blair Formation and Black Butte and Coulson Shale Tongues bf the Rock Springs Formation. Delta-front sandstones consist mainly of interdistributary shoreface deposits composed of sand redistributed from point sources by longshore currents. Preservation of distributary-channel and mouth-bar deposits is rare due to intense wave reworking. The shorelines were modified by large-scale storm events. Distributary-channel, crevasse-splay, overbank, crevasse-subdelta, interdistributary-bay, marsh, swamp, flood-tidal delta, and washover deposits accumulated behind delta-front sandstones, mostly in lower delta-plain environments. In this lower delta-plain setting, peat was deposited in freshwater forest swamps as isolated pods and linear belts behind delta-front sands. The resulting coal beds are thin, pinching and splitting to the southeast of the study area. In contrast, in more landward settings north of the study area, non-marine sequences contain thicker and more continuous coal beds that accumulated in the lower parts of upper delta-plain environments.
{"title":"Depostional [sic] Environments of the Rock Springs Formation, Southwest Flank of the Rock Springs Uplift, Wyoming","authors":"M. Kirschbaum","doi":"10.31582/rmag.mg.23.2.63","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.2.63","url":null,"abstract":"A record at an ancient delta system Is preserved in outcrops along the flanks of the Rock Springs Uplift, southwestern Wyoming. The deltaic Upper Cretaceous Rock Springs Formation of the Mesaverde Group was deposited during early Campanian time near the end of the regressive phase of the Niobrara cyclothem. On the southwest end of the Uplift, part of the delta system is exposed near the seaward edge of a series of transgressive/regressive sequences, which consist of intertonguing prodelta, delta-front, and delta-plain deposits. Eight major delta-front sandstones are vertically stacked and laterally continuous throughout the main study area, intertonguing with prodefta deposits of the Blair Formation and Black Butte and Coulson Shale Tongues bf the Rock Springs Formation. Delta-front sandstones consist mainly of interdistributary shoreface deposits composed of sand redistributed from point sources by longshore currents. Preservation of distributary-channel and mouth-bar deposits is rare due to intense wave reworking. The shorelines were modified by large-scale storm events. Distributary-channel, crevasse-splay, overbank, crevasse-subdelta, interdistributary-bay, marsh, swamp, flood-tidal delta, and washover deposits accumulated behind delta-front sandstones, mostly in lower delta-plain environments. In this lower delta-plain setting, peat was deposited in freshwater forest swamps as isolated pods and linear belts behind delta-front sands. The resulting coal beds are thin, pinching and splitting to the southeast of the study area. In contrast, in more landward settings north of the study area, non-marine sequences contain thicker and more continuous coal beds that accumulated in the lower parts of upper delta-plain environments.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121498802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-04-01DOI: 10.31582/rmag.mg.23.2.45
M. Bitter
Phosphatic pebbles (carbonate-fluorapatite) are common constituents of lag gravels found along Turonian (Upper Cretaceous) disconformities within the Frontier Formation in Natrona County, Wyoming. These pebbles are of two types: 1) phosphate nodules, and 2) phosphate-cemented sandstone clasts. The phosphate nodules contain organic matter and pyrite and formed in fine-grained sediments in a reducing environment. Organic matter was probably the major source of phosphate, although distributaries may also have supplied some phosphorus. The phosphate-cemented sandstone clasts contain fine- to coarse-grained sand, fish tooth fragments, and previously formed phosphate nodules. The isopachous rims of phosphate cement do not contain pyrite and are considered to have precipitated in an oxidizing environment very near the water-sediment interface. The lowest stratigraphic occurrence of phosphate-cemented clasts is in the upper Turonian which suggests formation during a transgression. Slow sedimentation associated with the transgression may have caused a relative increase in organic matter within the sediment and allowed phosphate-rich interstitial water to diffuse into the water column, precipitating carbonate-fluorapatite in the oxidized sands near the water sediment interface. The association of phosphate-cemented clasts with the upper Turonian disconformity suggests that they could serve as a useful stratigraphic marker to help identify the disconformity throughout Natrona County.
{"title":"Origin of Phosphatic Nodules and Cements in the Upper Cretaceous Frontier Formation, Natrona County, Wyoming","authors":"M. Bitter","doi":"10.31582/rmag.mg.23.2.45","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.2.45","url":null,"abstract":"Phosphatic pebbles (carbonate-fluorapatite) are common constituents of lag gravels found along Turonian (Upper Cretaceous) disconformities within the Frontier Formation in Natrona County, Wyoming. These pebbles are of two types: 1) phosphate nodules, and 2) phosphate-cemented sandstone clasts. The phosphate nodules contain organic matter and pyrite and formed in fine-grained sediments in a reducing environment. Organic matter was probably the major source of phosphate, although distributaries may also have supplied some phosphorus. The phosphate-cemented sandstone clasts contain fine- to coarse-grained sand, fish tooth fragments, and previously formed phosphate nodules. The isopachous rims of phosphate cement do not contain pyrite and are considered to have precipitated in an oxidizing environment very near the water-sediment interface. The lowest stratigraphic occurrence of phosphate-cemented clasts is in the upper Turonian which suggests formation during a transgression. Slow sedimentation associated with the transgression may have caused a relative increase in organic matter within the sediment and allowed phosphate-rich interstitial water to diffuse into the water column, precipitating carbonate-fluorapatite in the oxidized sands near the water sediment interface. The association of phosphate-cemented clasts with the upper Turonian disconformity suggests that they could serve as a useful stratigraphic marker to help identify the disconformity throughout Natrona County.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121793928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-04-01DOI: 10.31582/rmag.mg.23.2.37
L. Robinson, B. E. Barnum
The Lake Basin fault zone, which is the eastern extension of the Lewis and Clark line, is a structural lineament extending west-northwest across central Montana and consists mainly of en echelon northeast-striking normal faults that have been interpreted to be surface expressions of left-lateral movement along a basement wrench fault. Information gathered from recent field mapping of coal beds and from shallow, closely-spaced drill holes resulted in detailed coal bed correlations, which revealed another linear zone of en echelon faulting directly on the extended trend of the Lake Basin fault zone. This faulted area, referred to as the Sarpy Creek area, is located 30 mi (48 km) east of Hardin, Montana. It is about 10 mi (16 km) long, 8 mi (13 km) wide, and contains 21 en echelon normal faults that have an average strike of N 63° E. We therefore extend the Lake Basin fault zone 20 mi (32 km) farther southeast than previously mapped to include the Sarpy Creek area. The Ash Creek oil field, Wyoming, 60 mi (97 km) due south of the Sarpy Creek area, produces from faulted anticlinal structures that have been interpreted to be genetically related to the primary wrench-fault system known as the Nye-Bowler fault zone. The structural similarities between the Sarpy Creek area and the Ash Creek area indicate that the Sarpy Creek area is a possible site for hydrocarbon accumulation.
{"title":"Southeastern Extension of the Lake Basin Fault Zone in South-Central Montana: Implications for Coal and Hydrocarbon Exploration","authors":"L. Robinson, B. E. Barnum","doi":"10.31582/rmag.mg.23.2.37","DOIUrl":"https://doi.org/10.31582/rmag.mg.23.2.37","url":null,"abstract":"The Lake Basin fault zone, which is the eastern extension of the Lewis and Clark line, is a structural lineament extending west-northwest across central Montana and consists mainly of en echelon northeast-striking normal faults that have been interpreted to be surface expressions of left-lateral movement along a basement wrench fault. Information gathered from recent field mapping of coal beds and from shallow, closely-spaced drill holes resulted in detailed coal bed correlations, which revealed another linear zone of en echelon faulting directly on the extended trend of the Lake Basin fault zone. This faulted area, referred to as the Sarpy Creek area, is located 30 mi (48 km) east of Hardin, Montana. It is about 10 mi (16 km) long, 8 mi (13 km) wide, and contains 21 en echelon normal faults that have an average strike of N 63° E. We therefore extend the Lake Basin fault zone 20 mi (32 km) farther southeast than previously mapped to include the Sarpy Creek area. The Ash Creek oil field, Wyoming, 60 mi (97 km) due south of the Sarpy Creek area, produces from faulted anticlinal structures that have been interpreted to be genetically related to the primary wrench-fault system known as the Nye-Bowler fault zone. The structural similarities between the Sarpy Creek area and the Ash Creek area indicate that the Sarpy Creek area is a possible site for hydrocarbon accumulation.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126059203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1986-04-01DOI: 10.1306/AD46238F-16F7-11D7-8645000102C1865D
D. B. Segal, M. Ruth, I. S. Merin, H. Watanabe, K. Soda, O. Takano, M. Sano
Examination of a variety of remotely sensed data and geochemistry suggest that specific diagenetic mineral assemblages within the Wingate Formation are closely associated with hydrocarbon production at Lisbon Valley, Utah. The Wingate Formation, exposed along the southwestern flank of the anticline has a relatively uniform composition and appearance over the entire Colorado Plateau, except at isolated localities such as Lisbon Valley, where it is locally bleached. Previous workers have suggested that hydrocarbon microseepage may account for the bleaching of the Wingate Sandstone and the presence of uranium mineralization in rocks overlying the reservoir at Lisbon Valley. Broad-band Landsat Multispectral Scanner (MSS) and airborne Thematic Mapper Simulator (TMS) data were used to map the bleached facies on the basis of brightness and lack of ferric iron. The TMS data provided further discrimination of bleached facies based on the relative abundances of clay minerals detectable with this sensor. Analysis of high-resolution airborne spectroradiometric data, thin sections, and x-ray diffraction data suggests that bleached rocks overlying the reseNoir at Lisbon Valley contain abundant kaolinite and minor amounts of feldspar. Unbleached exposures contain substantially less clay and abundant feldspar. This study shows a correlation between the abundance of clay minerals, particularly kaolinite, and hydrocarbon production at Lisbon Valley. Because one of the principal mineralogical differences between the bleached and unbleached rocks is the relative abundance of clay minerals, and the TMS (and Landsat Thematic Mapper) data are very sensitive to clays, areas of potential hydrocarbon induced diagenetic alteration may be mapped using broad-band sensors.
{"title":"Remote Detection of Anomalous Mineralogy Associated With Hydrocarbon Production, Lisbon Valley, Utah","authors":"D. B. Segal, M. Ruth, I. S. Merin, H. Watanabe, K. Soda, O. Takano, M. Sano","doi":"10.1306/AD46238F-16F7-11D7-8645000102C1865D","DOIUrl":"https://doi.org/10.1306/AD46238F-16F7-11D7-8645000102C1865D","url":null,"abstract":"Examination of a variety of remotely sensed data and geochemistry suggest that specific diagenetic mineral assemblages within the Wingate Formation are closely associated with hydrocarbon production at Lisbon Valley, Utah. The Wingate Formation, exposed along the southwestern flank of the anticline has a relatively uniform composition and appearance over the entire Colorado Plateau, except at isolated localities such as Lisbon Valley, where it is locally bleached. Previous workers have suggested that hydrocarbon microseepage may account for the bleaching of the Wingate Sandstone and the presence of uranium mineralization in rocks overlying the reservoir at Lisbon Valley. Broad-band Landsat Multispectral Scanner (MSS) and airborne Thematic Mapper Simulator (TMS) data were used to map the bleached facies on the basis of brightness and lack of ferric iron. The TMS data provided further discrimination of bleached facies based on the relative abundances of clay minerals detectable with this sensor. Analysis of high-resolution airborne spectroradiometric data, thin sections, and x-ray diffraction data suggests that bleached rocks overlying the reseNoir at Lisbon Valley contain abundant kaolinite and minor amounts of feldspar. Unbleached exposures contain substantially less clay and abundant feldspar. This study shows a correlation between the abundance of clay minerals, particularly kaolinite, and hydrocarbon production at Lisbon Valley. Because one of the principal mineralogical differences between the bleached and unbleached rocks is the relative abundance of clay minerals, and the TMS (and Landsat Thematic Mapper) data are very sensitive to clays, areas of potential hydrocarbon induced diagenetic alteration may be mapped using broad-band sensors.","PeriodicalId":101513,"journal":{"name":"Mountain Geologist","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134126922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：