Browsing by Subject "North-Central Texas"

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Faunal analysis of Permo-Carboniferous shales, North-Central Texas
(1978) Carew, James L.; Bell, W. Charles, 1911-1979
For the purpose of studying the nature of shelled marine invertibrate faunas that inhabited muddy bottom environments during a segment of the geologic past, fossil collections containing approximately 30,000 specimens were obtained from shale beds at thirty-two localities in North-Central Texas. The collections come from rocks ranging in age from Desmoinesian (Middle Pennsylvanian) to Wolfcampian (Early Permian). Brachiopods, bivalves, gastropods, and proifera were systematically studied and identified to species level. All other specimens were identified at higher taxonomic levels. A new species of pseudozygopleurid gastropod is identified. Fossils collected from bulk samples were identified and tabulated for statistical analyses. Sediment parameters were also entered into the computations, and various elements of faunal composition were compared with sediment composition. Q-mode cluster analysis shows that these faunas can be statistically grouped into three general community-types or assemblages. One is an association of taxa numerically dominated by sponges and with a low diversity of other species. These assemblages are laterally associated with carbonate banks. A second grouping includes assemblages dominated by brachiopods and containing an unusually large number of bryozoa. These faunas are of moderate diversity and abundance. The third community-type is the most variable in composition but is usually characterized by the dominance of mollucs. These assemblages are the most diverse and have the highest abundances. All of these assemblages or community-types can be compared to communities of other authors. Q- versus R-mode cluster analysis delineates those taxa most influential in the clustering of faunas. Comparison of the faunal data with sediment parameters reveals a strong correlation between increased carbonate content of the shale and increased brachiopod content of the fauna. A strong negative correlation exists between carbonate content and faunal diversity. As the depositional environment of the study area at that time consisted of delta complexes prograding onto a shallow carbonate platform, these trends are interpreted as reflecting faunal variation that is a function of the rate of influx of fine grained clastic material. At least in this area, the distribution of organisms and faunal communities that has previously been correlated with distance from shore and increasing water depth can be more accurately correlated with the rate of supply of fine grained sediment. Thus, animal communities previously assumed to represent an on-to offshore gradation may be distributed in any orientation to the shoreline along a gradient of decreasing fine grained sediment influx. Faunas rich in brachiopods seem to have preferred clear, less turbid, more calcareous environments, while the molluscs (especially gastropods) thrived in the more turbid muddy areas. One species of brachiopod, Crurithyris planoconvexa, has been interpreted to behave as an explosive opportunist; occurring in huge numbers after theorized reductions in the salinity of the environment as a result of increased fresh water run-off. Although the units sampled span the Pennsylvanian-Permian boundary, the statistical studies indicate that among these faunas there is no significant change in the megafossil fauna
Pennsylvanian bituminous coal, North-Central Texas: potential for coalbed methane resource development
(2003) Kim, Eugene M.
The most recent U.S. Geological Survey National Coal Resources Data System (NCRDS) activities completed for the State of Texas by the Bureau of Economic Geology (BEG) focused on Wilcox Group deep coal (lignite) resources, including defining coalbed methane exploration fairways in East-Central Texas (Tyler and Scott, 1999) and deep-basin coal (lignite) in Wilcox Group, Sabine Uplift, East Texas: potential for unconventional coalbed methane resource development (Kim and Ruppel, 2001). The major objectives of these projects were to provide high-quality, organized digital information and interpretations on the location, quality, and quantity of the coal to be mined in the Wilcox Group, Texas Gulf Coast area, during the next several decades to meet the needs of the region and the nation for reliable, low-cost, environmentally compatible energy. The first commercial coalbed methane field in Texas, the Sacatosa coalbed methane field in Maverick County, was announced in 2001 by The Exploration Company. This field is currently being produced from bituminous coal and carbonaceous shale of the Upper Cretaceous Olmos Formation in the Maverick Basin. Although the Pennsylvanian bituminous coals of North-Central Texas are of a rank higher than that of Texas Gulf Coast lignites and are comparable to Olmos bituminous coals, very little current information exists on their occurrence, distribution, geological setting, or future potential for coalbed methane development. More detailed and updated information on the coal resource in this region is essential for inclusion in the NCRDS, utilizing digital databases of available data as well as digitized maps compiled in a Geographic Information System (GIS) platform. The Pennsylvanian bituminous coals of North-Central Texas are of higher rank and thereby have higher Btu values than Texas Gulf Coast lignites. Moreover, they are also closer to the major energy user market of the Dallas-Fort Worth area. However, owing to their high sulfur/ash content and thin beds, commercial mining and potential for coalbed methane in these coals is limited.
Pennsylvanian Bituminous Coal, North-Central Texas: Potential for Coalbed Methane Resource Development
(2002) Kim, Eugene M.
Most recent U.S. Geological Survey National Coal Resources Data System (NCRDS) activities completed for the State of Texas by the Bureau of Economic Geology (BEG) focused on Wilcox Group deep coal (lignite) resources, including "Defining coalbed methane exploration fairways in East-Central Texas" (Tyler and Scott, 1999) and "Deep-basin coal (lignite) in Wilcox Group, Sabine Uplift, East Texas: potential for unconventional coalbed methane resource development" (Kim and Ruppel, 2001). The major objectives of these projects were to provide high-quality, organized digital information and interpretations on the location, quality, and quantity of the coal to be mined in the Wilcox Group, Texas Gulf Coast area, during the next several decades to meet the needs of the region and the nation for reliable, low-cost, environmentally compatible energy. The first commercial coalbed methane field in Texas, the Sacatosa coal bed methane field in Maverick County, was announced in 2001 by The Exploration Company. This field is currently being produced from bituminous coal and carbonaceous shale of the Upper Cretaceous Olmos Formation in the Maverick Basin. Although the Pennsylvanian bituminous coals of North-Central Texas are of higher rank than the Texas Gulf Coast lignites and are comparable to the most bituminous coals, very little current information exists on their occurrence, distribution, geological setting, or future potential for coalbed methane development. More detailed and updated information of the coal resource in this region is essential for inclusion in the NCRDS, utilizing digital databases of available data as well as digitized maps compiled in a Geographic Information System (GIS) platform. Providing updated digital data on the Pennsylvanian bituminous coals of North-Central Texas and assessing their potential for future coalbed methane resource development are the major objectives for this current study. Major accomplishments for FY02 included digitally compiling major background regional data for Pennsylvanian depositional systems and major coal resources such as the Strawn (Thurber) coals, as well as a comparison with current coalbed methane production from Olmos bituminous coals in the Maverick Basin. Future FY03 tasks to be completed include analysis of other coal resources such as the Canyon (Bridgeport) and Cisco (Newcastle) coals, as well as an overall future assessment of the coalbed methane potential of the Pennsylvanian bituminous coals of North-Central Texas.
Stratigraphy of the Pennsylbanian Formations of North-Central Texas
(University of Texas at Austin, 1921-06-05) University of Texas at Austin