Browsing by Author "Caran, S. Christopher"

Now showing 1 - 15 of 15

Delineation and Environmental Geologic Evaluation of Abandoned Coal Mines in North Central Texas
(1979) Finley, Robert J.; Caran, S. Christopher; Hupp, William H.
An environmental geologic survey of abandoned bituminous coal mines in North-Central Texas located 140 confirmed and probable mines in 12 counties. Previously, 67 mines were known, although some locations were found to be inaccurate. Present surface conditions at the mine sites have been evaluated relative to the need for possible reclamation. Based on the oldest available (and more recent) 1:20,000 to 1:40,000 scale aerial photography, low-altitude aerial observation, and ground confirmation, mining and subsequent mine abandonment have resulted in five major effects. These are: Devegetation, in part due to leachates from mine spoil. Erosion by gullying, sheetwash, and mass wasting. Increased sedimentation in tanks and streams. Ground surface subsidence. Accumulation of mine spoil, deteriorated equipment, and other refuse. The coals, mined from the 1850s to the 1940s, are in the middle and late Pennsylvanian Strawn, Canyon, and Cisco Groups. Mining was primarily underground by a modified longwall advancing method. A total of 585 acres has been affected by mining, with 142 acres in Young County (13 confirmed mines), 94 acres in Palo Pinto County (16 confirmed mines), and 45 acres in Wise County (15 confirmed mines). The greatest surface effects are evident near Thurber in Erath County and at Strawn in Palo Pinto County, where extensive spoil piles are present. Near Bridgeport in Wise County, shale in the spoil piles has been used in brick-making. Presently there is renewed interest in these bituminous coal resources, and exploration is active.
Environmental geology of abandoned lignitic- and bituminous-coal mines of Texas
(1984) Caran, S. Christopher; Young, Keith, 1918-2004
Lignitic, canneloid, and bituminous coals have been mined in Texas since at least the early 1800's and possibly the 1750's. Inactive mining districts are located in most regions of the state and mining continues in several areas. The mined seams of coal lie within sedimentary sequences of the Upper Pennsylvanian, Upper Cretaceous, and lower and middle Eocene Series. Most of the production before 1924 was from underground mines, whereas all coal extracted since the late 1940's has come from surficial mines. Prior to the 1970's, few mines were reclaimed. Consequently, many sites of abandoned coal mines in the state exhibit a wide range of adverse, environmental-geologic conditions, varying both in type and intensity. Conditions at these sites include: subsidence and faulting; effects of combustion; production of toxic, geochemical leachates; erosion, sedimentation, and effects on drainage; and the presence of open mine shafts, structural and mechanical debris, large spoil mounds, and miscellaneous refuse. Quantitative assessments of these conditions at selected sites were qualitatively extrapolated to other areas to permit evaluation of conditions statewide. Some of the most severely affected sites have been reclaimed under the regulatory authority of the Railroad Commission of Texas and by the U.S. Soil Conservation Service. Of the more than 260 sites of abandoned coal mines in Texas perhaps one-fourth eventually may require some corrective attention.
Future Climatic and Envirornmental Conditions in the Texas Panhandle- A Geological Perspective
(1985) Caran, S. Christopher
Among the many factors to be considered in planning a high-level nuclear waste repository in northwestern Texas are future climatic conditions and their role in affecting environmental change. In future millennia, the regional climate will almost certainly undergo episodic variations comparable to those inferred from the paleoclimatic record of the late Quaternary Period. In addition, local and perhaps global weather patterns may change in ways not previously sustained, as a consequence of inadvertent and possibly deliberate human activities. If the scope and duration of these natural and induced climatic changes were significant, they would appreciably influence geomorphic and geohydrologic processes in the Texas Panhandle.
Geologic Review of Propsed Amarillo Area Site for the Superconducting Super Collider (SSC)
(1987) Raney, J. A.; Gustavson, Thomas C.; Caran, S. Christopher
In June 1987, the Texas National Research Laboratory Commission commissioned the Bureau of Economic Geology at The University of Texas at Austin to conduct a review and brief report on the geology of the proposed site for the Superconducting Super Collider (SSC) in the Amarillo area. They also requested a surface geologic map of the site. An informal task force was assembled for this purpose, including Jay A. Raney (Coordinator), Thomas C. Gustavson, and S. Christopher Caran from the Bureau of Economic Geology. This report is accompanied by the geologic map (Plate 1) of the proposed Amarillo area site in the Texas Panhandle.
Geothermal Potential along the Balcones/Ouachita Trend, Central Texas--Ongoing Assessment and Selected Case Studies
(1984) Woodruff, Jr., C. M.; McPherson, G. L.; Gever, Christine; Caran, S. Christopher; El Shazly, Ahmed G.
Numerous wells produce warm groundwater from several Cretaceous aquifers located beneath the innermost part of the Texas Gulf Coastal Plain. The changes in landscape between the Coastal Plain and the uplands farther west result from a major geologic break. Texas is bisected along this trend by the Texas Craton, a hinge zone that separates the downwarping Gulf Coast Basin from the more stable continental interior. At depth, this hinge is defined by the subsided Ouachita Mountains; at the surface, the geologic break is expressed by the Balcones and Luling-Mexia-Talco Fault Zones. The geologic hinge zone has clearly affected the physiography of the region. These effects include abrupt changes in terrain, climate, soils, vegetation, and availability of groundwater across the hinge. These changes have, in turn, influenced human settlement patterns (Bybee, 1952). The Balcones/Ouachita hinge is a geocultural break similar in cause and comparable in effect to the Fall Line of the Eastern United States (Woodruff, 1980). Both trends are the loci of cities. The towns and cities along the Balcones/Ouachita trend might use the thermal resources; at some localities, the warm water is already used although as drinking water and not generally for its energy content. Studies at the Bureau of Economic Geology have documented geothermal waters in many places across Texas (Henry, 1979; Henry and Gluck, 1981; Woodruff and others, 1982). Locally, these waters may be hotter or more abundant than along the Balcones/Ouachita trend, but considering both geologic and socioeconomic aspects, Central Texas is probably the region with the greatest potential for developing a cost-effective energy resource from low-temperature geothermal waters. The cities along the Balcones/Ouachita trend constitute a market for the geothermal energy resource.
Lineament analysis and inference of geologic structure: examples from the Balcones Ouachita trend of Texas
(University of Texas at Austin. Bureau of Economic Geology, 1982) Caran, S. Christopher; Woodruff, C. M.; Thompson, Eric J.
Lineaments perceived in remotely sensed images are reliable indicators of geologic structure. Lineaments on ten Landsat multispectral scanner images (band 5; 1:250,000 scale) were mapped covering the Ouachita/Balcones-Luling-Mexia-Talco structural trend between the Rio Grande and Red river in Texas. More than 5,000 lineaments were perceived in these images. Maps depicting the lineaments (individually and in various combinations) were compared with maps of structural/ tectonic features and geothermal gradient contours, noting instances of apparent correlation among these themes. Lineaments are correlative with the individual faults and the aggregate fault patterns of the Baicones, Luling, Mexia, and Talco fault zones, Transverse lineaments, which trend almost perpendicular to these fault zones, mark the northernmost extent of the Balcones fault system and outline carbonate piatforms, such as the Belton High/Moffat Mound trend and the San Marcos arch. Transverse lineaments are coincident also with the axes of the buried Chittim and Preston anticlines and with the flanks of the Sherman and Round Rock synclines. Numerous salt domes occur at depth in the western part of the east Texas basin near the trend; many of these domes, particularly those in Henderson, Anderson, and Freestone Counties, are found along and at the intersection of major lineament zones where the concentration of individuai lineaments is greatest. Most of the buried Late Crelaceocs volcanoes of central Texas near Austin lie along northeast southwest- trending lineament zones; the altered pyroclastic rocks and associated beachrock facies at many of these volcanoes are hydrocarbon reservoirs. The orientation and spacing of geothermal gradient contour lines ("isograds") also correspond to major structures and thus, to the pattern of lineaments throughout the region. Correlation of (1)individual lineaments, zones of cortiguous or nearly parallel lineaments, and areas of homogeneous lineament density and orientation to (2) surface and subsurface structure and (3) geothermal,'isograd" patterns indicates that lineament analysis has many potential applications to regional mineral resource assessment.
Lineaments of Texas---Possible Surface Expressions of Deep-Seated Phenomena
(1984) Woodruff, Jr., C. M.; Caran, S. Christopher
Geologic structures are important controls on geothermal resources. Buried plutons, intrusions, or diapirs may provide either localized areas of high heat flow or zones of high thermal conductivity. Various structures such as faults, joints, folds, or buried massifs may affect underground fluid flow and thus may alter local thermal regimes. These subsurface hydrologic effects may either enhance or detract from geothermal potential because upwelling of deep-seated fluids increases local geothermal gradient, but recharge decreases geothermal gradient. Geologic structures provide direct controls on heat flow and indirect controls on geothermal gradients via hydrologic processes. Understanding geologic structures, especially buried structures, will therefore aid in assessing the geothermal potential of a given area. Some lineaments are surface indicators of geologic structures. An analysis of lineaments and an awareness of general hydrologic regimes provide means for delimiting promising areas for geothermal development. Lineaments, however, are polygenetic; not all linear features are related to earth structures at depth. Some are expressions of surface processes alone. Others seem to be essentially random alignments of features such as drainage, topography, soils, or vegetation, and the cause of many such features is unknown or ambiguous. Because of the varying quality of information imparted by individual lineaments, a high "noise-to-signal" ratio exists in lineament data. The geologist's task, in collecting lineament data and in subsequently analyzing them, is to winnow noise from signal—that is, to eliminate patterns that impart no geologic information, and thereby to ascertain which features are significant with respect to local or regional geologic structures. This process entails correlation of lineaments with other mapped features. For geothermal assessment, special emphasis must be placed on recognition of buried structures or other irregularities that may control thermal conditions in subsurface fluids. Using lineament analysis for ascertaining geothermal potential entails a consideration of the structural (subsurface) control on surface features—especially the recurring motifs of aligned features that constitute regional or statewide linear trends or "grain." In places, lineaments are clearly correlative with buried structures. But lineaments also occur in areas without known subsurface discontinuities, and lineaments also occur in many places that have no geothermal potential. Thus, lineament analysis as a prospecting tool must be used carefully. Some workers have tended to assume that the very presence of a lineament invariably implies geologic control. The data we obtained do not support such a view, but they do indicate that many lineaments are expressions of local structural conditions that may be otherwise hidden or subtle.
Modern Eolian Processes on the Southern High Plains
(1984) Machenberg, Marcie D.; Caran, S. Christopher
Eolian processes have substantially modified the landscape on the Southern High Plains within historic times. The maximum inferred rate of deflation was 18.9 mm/year at a site in Bailey County, Texas, a region of loose, sandy soils and frequent, seasonal dust storms. At least locally, agricultural practices have accelerated natural rates of erosion and deposition by winds. An extensive cover of windblown sand and silt mantles the gently sloping surface of the Southern High Plains. Eolian deflation and deposition are among the dominant geomorphic processes affecting this region throughout most of the Holocene and Pleistocene time. Historically, human activities have heightened the importance of wind action by disrupting the natural vegetative cover, thereby exposing the unconsolidated sediments. Agriculture, particularly dry-land cultivation, has been the principal form of land use in the area since the early 1900s or before (Webb, 1931). The effects of tilling practices on deflation are shown in Figure 1. The cultivated field on the right (east) is approximately 0.8 m lower than the range site on the left (west). This long, narrow field was cleared and probably brought into cultivation in the 1920s (C. D. Tunnell, personal communication, 1983). Its furrows run from north to south, along the field's long axis. The orientation of these furrows tends to maximize local deflation, as the furrows are parallel to the dominant winds. During the winter and early spring, some of the strongest winds are from the north, whereas the prevailing wind direction is southerly at other times of the year (Bomar, 1983). Other factors that enhance the erosional impact of the wind include antecedent dry conditions and frost heaving. Both are seasonal effects that increase the soil's susceptibility to removal during the frequent spring dust storms. After becoming entrained, soil aggregates from this field and others like it are transported from their source and redeposited as a broad sheet of eolian sediment.
Obtaining Practical Information on the Geology of Texas
(1983) Caran, S. Christopher; McBride, Mary W.
Information, like gold, is where you find it. Geological information is no exception, but in Texas such data are often readily at hand. The state has one of the highest concentrations of practicing geologists per capita in the United States; and Texans in general are very conscious of the importance of fossil fuels, earth materials, and land and water resources in the state's economy, history, and quality of life. But where does one turn for specific geological information? Fortunately, there are many sources of information on the geology of Texas, including: 1) State agencies 2) Federal agencies 3) Colleges and universities 4) Geological (and related) societies 5) Museums and nature centers 6) Oil, mining, and consulting companies 7) Public schools 8) Public libraries These organizations can often provide published information, films, lectures, and professional advice to persons requiring particular information as well as those who simply have a sincere interest in the geosciences. Most of the state and federal agencies, colleges and universities, and geological societies that engage in studies of the geology of Texas are listed in the accompanying appendices (A, B, C, and D), along with their addresses, telephone numbers, and summary statements of their areas of involvement or expertise.
Paleoclimatic Reconstruction Based on Molluscan (Gastropoda, Pelecypoda) Environmental Indicators-Late Quaternary of Northwestern Texas
(1985) Caran, S. Christopher; Neck, Raymond W.; Fullington, Richard Wayne
Paleoecologic interpretation of fossil molluscan faunas provides a basis for indirect reconstruction of paleoclimates. Terrestrial and aquatic mollusks are abundant in late Quaternary sedimentary deposits of the western Rolling Plains of Texas. These taxa compose a succession of distinct faunal assemblages. Most mollusks represented in late Pleistocene to middle Holocene assemblages of the region are absent from the modern fauna. However, none of the extirpated species are extinct; their distribution has merely been reduced such that at present, these taxa are found northeast or in montane areas west of the Southern High Plains and Rolling Plains. Because they are living species, their environmental requirements, habitat, and climate are relatively well known. Environments that sustain these mollusks today are presumed to have existed in northwestern Texas in the past. Ecological conditions throughout the Pleistocene and Holocene Epochs can be inferred by tracing the range of environmentally sensitive taxa through radiocarbon-dated stratigraphic sequences. Allowance is made for local variations owing to facies changes and temporary modifications of habitat. Conditions in this region during the late Pleistocene favored diverse molluscan faunas. By comparison, the living fauna is depauperate and virtually restricted to species with broad environmental tolerances; climatic and ecological change was gradual, affecting different species at different times. Regional extirpation of a number of species with comparable ecologic requirements indicates a profound change in environment probably related to climate. Data from three well-constrained stratigraphic sections permit refinement of existing paleoclimatic reconstructions. Climatic variations during the Holocene have taken two related but somewhat independent paths. A summer warming trend that began in the latest Pleistocene greatly increased temperatures by about 8,000 years before present. A similar trend toward desiccation was accelerated between 8,000 and 6,000 years before present until essentially modern conditions were attained 3,000 years before present. Other, comparatively minor fluctuations of the regional paleoclimate are evident as well.
Quaternary Faulting in Southeastern Briscoe County, Texas
(1984) Baumgardner, Jr., Robert W.; Caran, S. Christopher
Downwarped and penecontemporaneously faulted beds of late Quaternary terrigenous sediment are well exposed in southeastern Briscoe County, Texas. Deformation probably was caused by subsidence of the Permian subcrop owing to dissolution of bedded salt at depth. Fluvial sands and gravels and lacustrine clays fill a subsidence basin, producing a locally thickened Quaternary section. A well-developed paleosol above lacustrine deposits was tilted and laterally truncated prior to modern eolian deposition at the site. Active, recently active, and inactive subsidence features are common in the western Rolling Plains of Texas. Most of these features are small, karstic sinkholes up to 330 ft (100 m) in diameter and subsidence basins a few miles long. Gustavson and others (1982) investigated more than 400 of these features (dolines) in Hall and Briscoe Counties, Texas. These structures formed and are forming as a result of dissolution of Upper Permian (Ochoan and Guadalupian) evaporites, particularly halite, at depths of 650 to 1,000 ft (200 to 300 m) (Gustavson and others, 1982; McGookey and others, in press). A similar pattern of karstic subsidence produced features of comparable size throughout late Pleistocene and Holocene time. During this interval, subsidence may have been more widespread than it is today because of the wetter climate and presumably greater rates of infiltration and transmissibility of ground water in the late Pleistocene (Carr and McGookey, in press). The moist climate of the late Pleistocene turned sinkholes and subsidence basins into pluvial ponds and lakes, the largest of which probably also received phreatic discharge. Limnic and lacustrine deposits occupy a stratigraphically consistent position in the Quaternary section of the western Rolling Plains. At one site, these deposits are more than 30 ft (9.1 m) thick and show evidence of structurally enhanced deposition.
Quaternary Stratigraphy of the Western Rolling Plains of Texas Preliminary Findings
(1988) Caran, S. Christopher; Baumgardner, Jr., Robert W.; McGookey, Douglas A.
Quaternary deposits, as much as 76 m (250 ft) thick, discontinuously cover more than 7,800 km2 (3,000 mi2) of the western Rolling Plains of northwestern Texas. The stratigraphy of this sedimentary sequence is complex, reflecting changes in paleoclimate during the late Pleistocene and Holocene Epochs. In addition, there are clear indications of syngenetic structural control of deposition and postdepositional deformation of the Quaternary strata. These effects were caused by regional and local karstic subsidence resulting from dissolution of Upper Permian evaporites, particularly halite, at depths of 120 to 240 m (400 to 800 ft). Dissolution created voids within the bedded evaporites. As the voids expanded, the overlying strata collapsed, forming depressions wherein sediment accumulated preferentially. Subsidence also caused local faulting and downwarping of some of the Quaternary deposits. Affected deposits include beds of coarse-grained sediment eroded from the westward-retreating Caprock Escarpment (adjacent to the Rolling Plains). This sediment was trapped within the zone of subsidence, forming a broad bajada at the base of the escarpment. At most sites, the coarse-elastic deposits compose the lowest of three genetic components of the regional Quaternary section.
Radiocarbon Age of Quaternary Deposits, Western Rolling Plains of Texas
(1985) Caran, S. Christopher; Baumgardner, Jr., Robert W.
Four laboratories have made more than fifty finite radiocarbon-age determinations on samples from Quaternary deposits covering a large area of the Rolling Plains. These dates span the period from the late Pleistocene Epoch (23,255 ± 2,335 yr B.P.) virtually to the present. Caran and Baumgardner (1984) described a previously unrecognized sedimentary sequence covering more than 7,800 km2 (3,000 mi2) of northwestern Texas. At the time that report was prepared, only a few relevant radiocarbon-age determinations were available. The number of reliable finite dates has now increased to more than fifty, the oldest of which is 23,255 ± 2,335 yr B.P. Older infinite dates and a few questionable finite determinations also have been obtained, some of which were reported previously by other investigators.
Regional structural cross-sections, Mid-Permian to Quaternary strata, Texas Panhandle and eastern New Mexico; Mapping of Quaternary of Rolling Plains
(University of Texas at Austin. Bureau of Economic Geology, 1988) McGookey, Douglas A.
The Palo Duro Basin of the Texas Panhandle and eastern New Mexico contains bedded Permian salts of sufficient thickness and depth for the basin to be considered as a potential site for long-term storage and isolation of high-level nuclear waste. Salt (primarily halite) is a desirable host rock because of its low permeability, high thermal conductivity, low moisture content, and high gamma-ray shielding properties (Johnson, 1976b). A major concern that was addressed during the waste isolation study of the Texas Panhandle region is the long-term integrity of the bedded-salt host rock. Areas where salt has been removed by dissolution have been identified beneath the Southern High Plains, along the eastern and western escarpments of the Southern High Plains, and along the Canadian River valley (Gustavson and others, 1980b; Presley, 1980a, 1980b; Gustavson and Finley, 1985; Gustavson, 1986). Regional cross sections of mid-Permian to Quaternary strata in the Texas Panhandle and east- ern New Mexico illustrate lithologic and structural relations that are interpreted to have resulted from the regional dissolution of salt and the collapse of overlying strata. The cross sections were constructed using gamma-ray logs, sample logs, and surface geologic maps (Handford, 1980a; McGillis, 1980). Gamma-ray logs are shown on the cross sections because they best demonstrate variations in evap- orite strata. Figure 1 is an index map depicting the locations of the cross sections. Stratigraphic nomen- clature used on the cross sections is given in table 1.
Stratigraphy of a Playa-Lake Deposit Within the Proposed Alignment of the Amarillo-Area Superconducting Super Collider
(1987) Caran, S. Christopher
A limited investigation of playa-lake stratigraphy was conducted at a small unnamed playa approximately one mile northeast of Nazareth, Castro County, Texas (figs. 1, 2). This work was done in support of a study of the proposed Amarillo-area site for the Superconducting Super Collider (SSC) and is intended to complement discussion of the areal geology of the Amarillo-area site by Raney and others (1987). Three shallow boreholes (B6, B6A, and B6B) were drilled in the northeastern quadrant of the playa (fig. 1 inset). Borehole B6 was drilled near the center of the playa basin, B6A approximately half the playa radius to the northeast, and B6B farther northeast, just outside the playa margin. The three boreholes are aligned along a directional azimuth of N68E. Core was collected from each of the boreholes using Shelby tubes. The depth of all three was approximately 70 ft. The playa contained standing water at the time of coring; equipment access was afforded by a narrow levee road constructed across the playa floor. Boreholes B6 and B6A were drilled through the road fill. Playa deposits are among the most common late Cenozoic stratigraphic units in the Southern High Plains (fig. 2). The number of playas in the Southern and Central High Plains of Texas may exceed 37,000 (Schwiesow, 1965). Several playas are located near the proposed alignment of the Amarillo-area SSC (fig. 2). Despite their large collective areal extent and a long history of scientific interest in playas in general, the age and origin of deposits filling playa basins in this region remain highly controversial (see brief discussion by Raney and others, 1987). Playas are ephemeral lakes; their deposits typically include a mix of lacustrine and eolian sediments. Lacustrine silty clay and eolian fine sandy silt deposits of varying thickness are found in playas throughout the study area. Although the composition of playa deposits has been reasonably well characterized, the mechanisms by which their associated basins form and are maintained are not fully understood. At many sites, modern playa basins are inset into older lacustrine deposits, indicating possible genetic cyclicity. A variety of mechanisms may be involved in creating and maintaining playas as a group, and many individual playas may be polygenetic.