Search USGS⌕ Search

SEARCH · Search USGS

Results for “AAPG Studies in Geology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
USGS2011

A review of lignite resources of western Tennessee and the Jackson Purchase area, western Kentucky

This review of the lignite deposits of western Tennessee and the Jackson Purchase area in western Kentucky (Figure 1) is an updated report on part of the U.S. Geological Survey's National Coal Resource Assessment of the Gulf Coastal Plain Coal Province (see Ruppert et al., 2002; Hackley et al., 2006; Dennen, 2009; and other chapters of this publication). Lignite deposits of western Kentucky and Tennessee are an extension of the Gulf Coastal Plain Coal Province (Cushing et al., 1964), and currently are not economic to mine. These deposits have not been extensively investigated or developed as an energy resource. This review includes a description of the geology of the lignite-bearing units, a discussion of the available coal quality data, and information on organic petrology. Palynological data for lignite samples collected in Kentucky and Tennessee as part of this work are presented in Table 1. Lignite trace element data originally presented in Hackley et al. (2006) are not included in this report due to potential laboratory quality control issues during the time the samples were analyzed (U.S. Geological Survey Energy Resources Program, 2010).

Kentucky, Tennessee↗
USGS2011

Bibliography of the Gulf of Mexico coastal plain coal geology

Unlike scientific literature pertaining to most other coal-bearing regions in the conterminous United States, this bibliography on the coal geology of the Gulf Coastal Plain is dominated by work from the late 20th century. Although coals of this region were mined commercially in the late 1800s and early 1900s, they were eclipsed by the production and use of oil and gas in the middle 1920s and were not mined again as a significant fuel source until the 1970s. As a result, the literature consists mainly of a relatively small number of pre-1920 contributions in state and federal reports, followed by a plethora of technical papers, symposia proceedings, field guides, theses, dissertations, and abstracts over the past 40 years. The purpose of this chapter is to record the present work used by U.S. Geological Survey personnel preparing the Gulf Coast Coal Resource Assessment and to furnish an introduction to the larger body of sedimentary, stratigraphic, paleontologic, geochemical, hydrologic, and mining literature that exists in the region. This bibliography is an update of an earlier compilation (Tewalt et al., 1990). Despite its length, it is not exhaustive. Nor is it restricted to papers that focus solely upon coals because an understanding of these coals is rooted in the general geologic literature of the Gulf Coastal Plain.

Louisiana, Texas↗
USGS2011

Coal resources for the Chemard Lake (Naborton No. 2) coal zone of the lower Wilcox group (Paleocene), northwestern Louisiana

The lower part of the Wilcox Group of northwest Louisiana contains shallow (less than 500 ft) coal deposits that are mined for use in mine-mouth electric power-generating plants. The coal deposits, which are lignite A in apparent rank (Pierce et al., 2011), occur on the eastern part of the Sabine uplift (Figure 1). The coal zones and associated strata in the assessment area generally dip away from the axis of the Red River-Bull Bayou dome that is located in the north-central part of the Louisiana Sabine assessment area (Figure 1). This assessment area includes parts of four parishes: De Soto, Red River, Natchitoches, and Sabine (Figure 2). The assessment area was selected because of its proximity to current mining areas and the availability of stratigraphic data in the area. The assessment area is roughly 60 miles long and 15 miles wide and generally extends across the central-eastern part of the Sabine uplift in northwest Louisiana (Figure 2). More than 950 stratigraphic records from rotary and core drill holes were used to assess the coal resources of the Louisiana Sabine area. Of these, 210 are public data points and are located in or near the areas that have been permitted or proposed for surface mining (Figure 2; Appendix 1). Most of the stratigraphic data used for this assessment were provided to the U.S. Geological Survey (USGS) on a confidential basis by various coal companies for use in regional studies.

Louisiana↗
USGS2011

Coal resources for part of the Wilcox group (Paleocene through Eocene), central Texas

The Wilcox Group of central Texas contains shallow (less than 500 ft) coal deposits that are mined for use in mine-mouth electric power generating plants. These coal deposits range in apparent rank from lignite to sub-bituminous (Pierce et al., 2011) and are similar in rank and composition to shallow coal deposits in the northeast and south Texas areas (Figure 1). The coal zones and associated strata in the central Texas assessment area generally dip to the southeast toward the Gulf of Mexico coastline and basin center. The central Texas resource assessment area includes parts of eight counties (Figure 2). The assessment area was selected to encompass current mining areas and areas with available subsurface stratigraphic data. The assessment area is roughly 160 miles long and 5 to 25 miles wide and generally follows the outcrop of the Paleocene to Eocene Wilcox Group in central Texas (Figures 1, 2). Approximately 1800 subsurface stratigraphic records from rotary and core drill holes were used to assess the resources of the central Texas assessment area. Of the 1800 drill holes, only 167 are public data points and are primarily located in the areas that have been permitted for surface mining (Figure 2; Appendix 1). The remaining 1632 drill holes, which are distributed throughout the assessment area, were provided to the U.S. Geological Survey (USGS) on a confidential basis by various coal companies for use in regional studies.

Texas↗
USGS2011

Eocene bituminous coal deposits of the Claiborne group, Webb County, Texas

Two bituminous coal zones, the San Pedro and the Santo Tomas, in the middle Eocene Claiborne Group of Webb County, south Texas (Figure 1), are among the coal resources that are not evaluated quantitatively as part of the current Gulf Coastal Plain coal resource assessment. Coal beds within these zones were mined by underground methods northwest of Laredo until 1939 and have been intermittently mined at the surface since 1979. These coals have long been regarded as unique within the Gulf Coast Tertiary coal-bearing section because they are high-volatile C bituminous in rank and because their physical characteristics resemble upper Carboniferous cannel coals of the Appalachians and Europe. Discontinuous exposures of the Santo Tomas and the underlying San Pedro coal zone extend northwestward from Dolores for approximately 15 to 21 mi along the breaks of the Rio Grande and its tributaries in Webb County (Figure 1). This part of south Texas lies along the southwestern flank of the Rio Grande Embayment, which extends south and southeastwardly through the Mexican States of Coahuila, Nuevo León, and Tamaulipas (Figure 1). Within the embayment, the lower to middle part of the Claiborne Group consists of marine mudstones (Reklaw Formation) in the east and northeast and sandstones and mudstones (Bigford Formation) in the south and southwest (Figure 2). The marine mudstones coarsen upward into fluvial-deltaic sandstones (Queen City Sand) that prograded gulfward across eastern and central Texas (Guevara and Garcia, 1972). To the west and southwest, the interval overlying the Bigford Formation becomes less sandy, and claystones (El Pico Clay) predominate. Although the San Pedro coal zone has been placed traditionally near the top of the Bigford Formation and the Santo Tomas coal zone near the base of the El Pico Clay, recent work has failed to validate a mappable contact between these formations (Warwick and Hook, 1995). The coal beds dip northeast at less than 2 degrees towards the synclinal axis of the basin. The following summary is based upon published and unpublished reports; drillhole records (geophysical logs, descriptions of cores and cuttings); coal-quality data obtained from the permit files of the Railroad Commission of Texas and recent sampling by the U.S. Geological Survey (USGS); a preliminary review of proprietary data acquired recently by the USGS; and field work conducted by the USGS since 1994. A total of approximately 200 drillhole records was examined.

Texas↗
USGS2011

A review of the lignite resources of Arkansas

This review of the lignite resources of Arkansas is a part of the U.S. Geological Survey's (USGS) National Coal Resource Assessment (NCRA) of the Gulf Coastal Plain Coal Province, which also includes coal-bearing areas in the states of Texas, Louisiana, Alabama, Mississippi, Tennessee, and Kentucky (see Ruppert et al., 2002 ; Dennen, 2009 ; and other chapters of this publication). Lignite mining is not planned in Arkansas in the immediate future, and the lignite resources of the state were not assessed in detail as part of the NCRA. This chapter includes reviews of the geology of the lignite-bearing units, historical mining, previous investigations of lignite resources, and coal quality. Palynological data for lignite samples collected in Arkansas as part of this work are presented in Table 1 .

Arkansas↗
USGS2001

Microbial lime-mud production and its relation to climate change

Microbial calcification has been identified as a significant source of carbonate sediment production in modern marine and lacustrine environments around the globe. This process has been linked to the production of modern whitings and large, micritic carbonate deposits throughout the geologic record. Furthermore, carbonate deposits believed to be the result of cyanobacterial and microalgal calcification suggest that the potential exists for long-term preservation of microbial precipitates and storage of carbon dioxide (CO 2 ). Recent research has advanced our understanding of the microbial-calcification mechanism as a photosynthetically driven process. However, little is known of the effects of this process on inorganic carbon cycling or of the effects of changing climate on microbial-calcification mechanisms. Laboratory experiments on microbial cellular physiology demonstrate that cyanobacteria and green algae can utilize different carbon species for metabolism and calcification. Cyanobacterial calcification relies on bicarbonate (HCO 3 – )utilization while green algae use primarily CO 2 . Therefore, depending on which carbonate species (HCO 3 – or CO 2 ) dominates in the ocean or lacustrine environments (a condition ultimately linked to atmospheric partial pressure PCO 2 ), the origin of lime-mud production by cyanobacteria and/or algae may fluctuate through geologic time. Trends of cyanobacteria versus algal dominance in the rock record corroborate this conclusion. These results suggest that relative species abundances of calcareous cyanobacteria and algae in the Phanerozoic may serve as potential proxies for assessing paleoclimatic conditions, including fluctuations in atmospheric PCO 2 .

AAPG Studies in Geology↗
USGS1987

Passive margins: U.S. Geological Survey Line 19 across the Georges Bank basin

Georges Bank is a shallow part of the Atlantic continental shelf southeast of New England (Emery and Uchupi, 1972, 1984). This bank, however, is merely the upper surface of several sedimentary basins overlying a block-faulted basement of igneous and metamorphic crystalline rock. Sedimentary rock forms a seaward-thickening cover that has accumulated in one main depocenter and several ancillary depressions, adjacent to shallow basement platforms of paleozoic and older crystalline rock. Georges Bank basin contains a thickness of sedimentary rock greater than 10 km, whereas the basement platforms that flank the basin are areas of thin sediment accumulation (less than 5 km).

AAPG Studies in Geology↗
USGS2011

Introduction

The National Coal Resource Assessment (NCRA) team of the U.S. Geological Survey (USGS) has assessed the quantity and quality of coal beds and zones that could be mined during the next 20 years or more. Geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States: the Appalachian Basin, Illinois Basin, Northern Rocky Mountains and Great Plains, Colorado Plateau, and the Gulf of Mexico Coastal Plain, (Gulf Coast) (Figure 1). In particular, the NCRA assessed coal-quality information and characterized environmentally significant trace elements, such as arsenic and mercury, that are defined in and administered by 1990 Clean Air Act Amendments (U.S. Environmental Protection Agency, 1990). The results of various USGS coal assessment efforts may be found at: http://energy.cr.usgs.gov/coal/coal_assessments/index.html, and a summary of the results from all assessment areas can be found in Ruppert et al. (2002) and Dennen (2009).

Louisiana, Texas↗
USGS2011

Front matter: Preface, acknowledgements, table of contents

This volume is the fifth in a series of reports by the U.S. Geological Survey (USGS) on the assessment of the quantity and quality of the nation’s coal deposits that potentially could be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States: the Appalachian Basin, Illinois Basin, Northern Rocky Mountains and Great Plains, Colorado Plateau, and the western part of the Gulf of Mexico Coastal Plain (Gulf Coast) region. The results of these other USGS coal assessments may be found at: http://energy.cr.usgs.gov/coal/coal_assessments/ index.html and a summary of the results from all assessment areas can be found in Ruppert et al. (2002) and Dennen (2009). This volume contains the assessment results for the Gulf Coast region. The contents of this volume were compiled mainly during the eight-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

AAPG Studies in Geology↗
USGS2011

Executive summary - Geologic assessment of coal in the Gulf of Mexico coastal plain, U.S.A.

The National Coal Resource Assessment (NCRA) project of the U.S. Geological Survey (USGS) has assessed the quantity and quality of the nation's coal deposits that potentially could be mined during the next few decades. For eight years, geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States: the Appalachian Basin, Illinois Basin, Northern Rocky Mountains and Great Plains, Colorado Plateau, and the western part of the Gulf of Mexico Coastal Plain (Gulf Coast) region (Figure 1). In particular, the NCRA assessed resource estimates, compiled coal-quality information, and characterized environmentally sensitive trace elements, such as arsenic and mercury, that are mentioned in the 1990 Clean Air Act Amendments (U.S. Environmental Protection Agency, 1990). The results of the USGS coal assessment efforts may be found at: http://energy.cr.usgs.gov/coal/coal-assessments/index.html and a summary of the results from all assessment areas can be found in Ruppert et al. (2002) and Dennen (2009). Detailed assessments of the major coal-producing areas for the Gulf Coast region along with reviews of the stratigraphy, coal quality, resources, and coalbed methane potential of the Cretaceous, Paleocene, and Eocene coal deposits are presented in this report (Chapters 5-10).

Gulf of Mexico coastal plain↗
USGS2011

Eocene Yegua Formation (Claiborne group) and Jackson group lignite deposits of Texas

The lignite deposits within the upper Eocene Yegua Formation (Claiborne Group) and the overlying Jackson Group are among the coal resources that were not quantitatively assessed as part of the U.S. Geological Survey's (USGS) National Coal Resource Assessment (NCRA) program in the Gulf Coastal Plain coal province. In the past, these lignite-bearing stratigraphic units often have been evaluated together because of their geographic and stratigraphic proximity (Fisher, 1963; Kaiser, 1974; Kaiser et al., 1980; Jackson and Garner, 1982; Kaiser, 1996) (Figures 1, 2). The term “Yegua-Jackson trend“ is used informally herein for the lignite-bearing outcrops of these Late Eocene deposits in Texas. Lignite beds in the Yegua-Jackson trend generally are higher both in ash yield and sulfur content than those of the underlying Wilcox Group (Figure 2 ). Recent studies (Senkayi et al., 1987; Ruppert et al., 1994; Warwick et al., 1996, 1997) have shown that some lignite beds within the Yegua-Jackson trend contain partings of volcanic ash and host elevated levels of trace elements that have been identified as potentially hazardous air pollutants (HAPs) in the United States Clean Air Amendments of 1990. Lignite beds within the Yegua Formation are thin (less than or equal to 6 ft) and laterally discontinuous in comparison with most Wilcox Group deposits (Ayers, 1989a); in contrast, the Jackson Group lignite beds range up to 12 ft in total thickness and are relatively continuous laterally, extending nearly 32 mi along strike.

Texas↗
USGS2011

A review of Alabama lignite deposits

This review of Alabama lignite deposits is a part of the U.S. Geological Survey (USGS) National Coal Resource Assessment (NCRA) of the Gulf Coast region (see Ruppert et al., 2002; Dennen, 2009; and other chapters of this publication). Because lignite is not currently mined in Alabama, a detailed assessment of the state was not made, and only a review is presented in this chapter. Lignite beds are found in several stratigraphic horizons within the Paleocene Midway and Paleocene to Eocene Wilcox Groups in the Gulf Coastal Plain of Alabama (Figure 1). There are three main near-surface (less than 250 ft of overburden) lignite deposits in Alabama. In the Midway Group, the Oak Hill lignite deposit occurs in the upper part of the Oak Hill Member of the Naheola Formation (Figure 2). In the Wilcox Group, the Gravel Creek and the Tuscahoma lignite deposits occur in the Coal Bluff Marl Member of the Nanafalia Formation and the Tuscahoma Sand Member of the Tuscahoma Sand Formation, respectively (Figure 2). The Gravel Creek lignite occurs in central and eastern Alabama, and the Oak Hill and Tuscahoma Sand lignites occur in southwest Alabama. Eighty-five percent of this lignite may be recoverable by surface mining methods (Tolson, 1985). The total amount of lignite reported as a reserve by the state is over 4.7 billion short tons (Self et al., 1978).

Alabama↗
USGS2004

Chronostratigraphic and depositional sequences of the Fort Union formation (Paleocene), Williston Basin, North Dakota, South Dakota, and Montana

The Fort Union Formation in the Williston Basin of North Dakota, South Dakota, and Montana comprises chronostratigraphic and depositional sequences of Paleocene age. Individual chronostratigraphic sequences are defined by palynostratigraphic (pollen and spore) biozones and radiometric ( 40 Ar/ 39 Ar) ages obtained from tonsteins or volcanic ash layers. Analyses of depositional sequences are based on lithofacies constrained by the radiometric ages and biozones. The lower Paleocene (biozones P1-P3) contains three marine parasequences (landward stepping) in southwestern North Dakota that sequentially onlapped westward between 65 and 61 Ma (lower Ludlow and Cannonball Members). Maximum flooding (transgressive systems tract) occurred during an approximate 1-m.y. interval from 65 to 64 Ma, which regionally is correlated biostratigraphically to a tidally influenced, distributary-shoreface, and fluvial-channel complex in the Cave Hills, northwestern South Dakota, and to channel-dominated fluvial (low-stand incised paleovalley systems) and tidally influenced, flood-plain-deltaic transition facies in the Ekalaka area of southeastern Montana. The progradational parasequences in the Cannonball Member consist of shore-face sandstone beds (with ravinement lag deposits) deposited by strand-plain barrier systems. Landward of the barrier systems, tidal-estuarine and mire deposits included thick but laterally discontinuous peat accumulations (e.g., Beta and Yule coal beds in the Ludlow Member, southwestern North Dakota). However, landward of the coastal deposits, the laterally equivalent T-Cross-Big Dirty coal zone (dated 64.78 Ma) in southeastern Montana formed as thick, laterally extensive peat accumulations in mires in a fluvial setting. In the flood-plain-deltaic, tidal transition zone near Ekalaka, Montana, the Ludlow Member consists of flood-plain facies, discontinuous coal beds, and rooted and burrowed horizons that contain the marine or brackish trace fossil Skolithos. The flood-plain-deltaic tidal transition zone facies are incised by a massive, agglomerated channel sandstone complex (paleovalley fill) that is exposed along the modern Snow Creek drainage south of Mill Iron, Montana. The flood-plain-tidal transition zone was reworked during the maximum sea level highstand during the early Paleocene. This event was followed by a fall of sea level and deposition of the paleovalley fill. Sea level fall during the mid-Paleocene (biozones P3 and P4) produced a regressive shallow-marine and lower deltaic tidal system (seaward stepping) that deposited strata that thin toward the east. These strata are overlain by a widespread paleosol (Rhame bed) and, in turn, a lignite-bearing fluvial facies (Tongue River Member) containing the laterally persistent Harmon-Hanson coal zone (61.23 Ma). Upper Paleocene biozone P5 is represented by fluvial, coal-bearing strata that contain several economically minable coal beds (HT Butte, Hagel, and Beulah-Zap zones, Sentinel Butte Member). The Fort Union Formation of the Williston Basin contains significant coal resources. These coal deposits are now being explored for their potential coal-bed gas resources. A better understanding of the depositional setting for these deposits can lead to improved exploration and exploitation practices and a better understanding of regional paleogeography and paleoclimate during the Paleocene.

Montana, North Dakota, South Dakota↗
USGS2011

Paleocene coal deposits of the Wilcox Group, Northeast Texas

The surface exposure of the Paleocene Wilcox Group in northeast Texas varies in width from 9 to 27 mi along an arcuate outcrop that extends southwest approximately 156 mi from the Texas-Arkansas State line to 32° latitude. Parts of Bowie, Camp, Cass, Franklin, Henderson, Hopkins, Morris, Navarro, Rains, Titus, Van Zandt, and Wood Counties are included in this outcrop belt (Figure 1). This area forms the northwestern flank of the East Texas Basin (Figure 2), the axis of which separates northeast Texas from the Sabine uplift structural area. The Wilcox Group dips south and southeast at 2° or less toward the axis of the East Texas Basin, with the exception of local salt-dome structures and a transcurrent structural high that extends from Monticello to Martin Lake (Figure 1).

Lousiana, Oklahoma, Texas↗
USGS2011

Paleocene coal deposits of the Wilcox group, central Texas

Coal deposits in the Wilcox Group of central Texas have been regarded as the richest coal resources in the Gulf Coastal Plain. Although minable coal beds appear to be less numerous and generally higher in sulfur content (1 percent average, as-received basis; table 1) than Wilcox coal deposits in the Northeast Texas and Louisiana Sabine assessment areas (0.5 and 0.6 percent sulfur, respectively; table 1), net coal thickness in coal zones in central Texas is up to 32 ft thick and more persistent along strike (up to 15 mi) at or near the surface than coals of any other Gulf Coast assessment area. The rank of the coal beds in central Texas is generally lignite (table 1), but some coal ranks as great as subbituminous C have been reported (Mukhopadhyay, 1989). The outcrop of the Wilcox Group in central Texas strikes northeast, extends for approximately 140 mi between the Trinity and Colorado Rivers, and covers parts of Bastrop, Falls, Freestone, Lee, Leon, Limestone, Milam, Navarro, Robertson, and Williamson Counties (Figure 1). Three formations, in ascending order, the Hooper, Simsboro, and Calvert Bluff, are recognized in central Texas (Figure 2). The Wilcox Group is underlain conformably by the Midway Group, a mudstone-dominated marine sequence, and is overlain and scoured locally by the Carrizo Sand, a fluvial unit at the base of the Claiborne Group.

Texas↗
USGS2011

Wilcox group (Paleocene to Eocene) coals of the Sabine Uplift area, Texas and Louisiana

The Wilcox Group (Paleocene to Eocene) of the Sabine uplift, a structural arch in northeastern Texas and northwestern Louisiana (Figure 1), has lignite zones that approach subbituminous rank (see Chapter 4, this publication). These coals are among the highest quality resources known within the Gulf Coastal Plain because of their low ash yield and sulfur content. The surface expression of the Sabine uplift is defined by the contact between coal-bearing rocks of the Wilcox Group and overlying fluvial rocks of the Carrizo Sand, which is the basal unit of the Claiborne Group (Figures 2, 3). The Sabine uplift study area includes parts of Harrison, Marion, Nacogdoches, Panola, Rusk, Sabine, San Augustine, and Shelby Counties in Texas and Bossier, Caddo, De Soto, Natchitoches, Red River, and Sabine Parishes in Louisiana (Figure 1). Adjacent counties and parishes that include the subsurface Wilcox Group extend the regional Sabine uplift area. The Wilcox in the subsurface is underlain by the Midway Group (Figure 3), a mudstone-dominated marine sequence of Paleocene age. Quaternary alluvium and terrace deposits overlying the Wilcox Group at the surface are limited to areas of modern drainage. The total thickness of the Wilcox Group within the Sabine uplift area ranges from approximately 400 ft on outcrop to 2500 ft in subsurface (Kaiser, 1990). In a few places, the contact between the overlying Carrizo Sand and Wilcox Group is erosional, but in other places, the contact is gradational.

Louisiana, Texas↗
USGS2011

Upper Cretaceous bituminous coal deposits of the Olmos Formation, Maverick County, Texas

This report describes the bituminous coal deposits of the Olmos Formation (Navarro Group, Upper Cretaceous; Figures 1, 2) of Maverick County in south Texas. Although these were not evaluated quantitatively as part of the current Gulf Coastal Plain coal-resource assessment, a detailed review is presented in this chapter. Prior to the late 1920s, these coal beds were mined underground on a large scale in the vicinity of Eagle Pass, Texas (Figure 1). Since the 1970s, Olmos Formation coals have been mined extensively in both underground and surface mines in nearby Coahuila, Mexico, to supply mine-mouth fuel for power generation at a plant nearby. A tract northeast of Eagle Pass was permitted in the late 1990s for surface mining. In east-central Maverick County, a coalbed methane field is being developed in coal beds of the lower part of the Olmos Formation (Barker et al., 2002; Scott, 2003).

Texas↗