Geological Circulars

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Peer-reviewed geoscience research summaries, targeted on Bureau project areas in Texas and other locations, 1965–2003.

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Bloating characteristics of east Texas clays
(University of Texas at Austin. Bureau of Economic Geology, 1965) Fisher, W. L. (William Lawrence), 1932-; Garner, L. E.
Incidence of bloating among approximately 600 clay samples from East Texas, ranging in age from Gulfian (Late Cretaceous) to Recent, correlates principally with clay mineralogy-and pH--together an indication of bulk composition--and to a lesser extent with texture, loss on ignition, and content of nonclay refractory minerals. Clay-mineral and pH data permit prediction of bloating with an accuracy of about 80 percent. Montmorillonitic and illitic clays are the best bloaters; bloating occurs in more than 80 percent of clays consisting of less than 30 percent kaolinite, more than l 0 percent illite, and between 20 and 90 percent montmorillonite. Only 10 percent of the high-alumina clays (more than 50 percent kaolinite) bloat; these generally are plastic and carbonaceous. Value of pH is an index of the amount of certain flux and gas-forming materials in clays; accordingly, bloating incidence generally increases with increase in pH. Incidence of bloating also increases slightly with decrease in grain size, increase in plasticity, increase in loss on ignition, and decrease in content of nonclay refractory minerals.
Texas mineral resources: problems and predictions
(University of Texas at Austin. Bureau of Economic Geology, 1965) Flawn, Peter Tyrell
When a reference is made to the mineral resources of Texas, most people think of oil and gas, and some few also of sulfur. And, of course, it is true that of the whopping $4.4 billion dollars' worth of minerals produced in Texas in 1963, 92% was oil, gas, and natural gas liquids. In 1963, for the 29th year, Texas led the Nation as a producer of minerals. Value of mineral products was twice the value of agricultural products, equal to the value of manufactured products, and equal to about one-half the value of all retail trade. It is clear that the State has a mineral-oriented economy; it is true also that the mineral industry is distributed broadly throughout the State and not concentrated in several giant oil fields or very large mines--241 of 254 counties reported mineral production in 1963. But in addition to oil and gas, Texas produced 22 other minerals last year valued at $361.7 million dollars. There are indeed many States which would happily settle for this 8 percent of Texas' mineral production. Significantly, this is the segment of Texas' mineral industry growing most rapidly, and it is the segment that will continue to grow.
Geology in the state government of Texas
(University of Texas at Austin. Bureau of Economic Geology, 1965) Flawn, Peter Tyrell
This circular presents the history of "geological survey" in Texas from its beginning in 1858, through its intermittent early history, to [1965]. It also shows that any organization which carried the name "survey" was very short-lived in Texas. Whether this is because of early legislators' convictions that a survey was something that was organized to do a specific job and then terminated, or whether there were deeper causes for the ephemeral nature of the early surveys is a matter for more thorough historical research and analysis.
A revision of Taylor nomenclature, Upper Cretaceous, Central Texas
(University of Texas at Austin. Bureau of Economic Geology, 1965) Young, Keith, 1918-2004
Since the days of R. T. Hill (1901) two Upper Cretaceous lithic units have been used as formations but have remained unnamed. These two units have usually been called the "Lower Taylor Marl" and the "Upper Taylor Marl". If Taylor is used as a group, both of these formations belong in the Taylor Group. If one uses Hill's division system of classification, the "Upper Taylor Marl" belongs to the Taylor Division but the "Lower Taylor Marl" belongs to the Austin Division, since it is a claystone lithosome interfingering with the type Austin Chalk and is genetically part of the Austin. Schuchert (1943, p. 900) may have been aware of some of the problems and some of the confusion rising out of this nomenclatural muddle when he applied the term "unnamed formation" to the unit generally termed "Lower Taylor Marl". The "Lower Taylor" and the "Upper Taylor" are separated by the Pecan Gap Formation (Stephenson, 1918) so that the lithic sequence is claystone, chalk (or marly limestone), and claystone. In more detailed maps of the greater area of Austin, Texas, the Pecan Gap is omitted by faulting in some areas, leaving the two claystone formations in fault contact. To eliminate confusion, it is imperative that the two unnamed claystone units be named.
Texas minerals: trends in production
(University of Texas at Austin. Bureau of Economic Geology, 1965) Fisher, W. L. (William Lawrence), 1932-
Minerals play a vital role in the economy of an industrial State. In Texas, where annual production of minerals currently amounts to more than $4. 5 billion--twice the value of agricultural products, equal the value of manufactured products, and equal to half the value of all retail trade--mineral production is the principal part of the State's economic foundation. Analyses of past production trends and economic factors allow predictions of future trends in this vital and important segment of the Texas economy. Included herein are production graphs and brief annotations of production trends of principal or representative Texas mineral commodities. Period considered is 1950 through 1964, a period embracing significant post-war developments in the State and National economy.
Fluorspar in Brewster County, Texas
(University of Texas at Austin. Bureau of Economic Geology, 1967) McAnulty, William Noel, 1913-
Since production of fluorspar began in northern Coahuila, Mexico, in 1950-51, thousands of tons of high-grade ore have been mined from numerous deposits situated 5 to 75 miles south of the Rio Grande. A large part of the fluorspar mined from these deposits has moved northward through Boquillas, Stillwell Crossing, and Heath Crossing to the railhead at Marathon, Texas. Consequently, Marathon has become one of the principal fluorspar shipping points in the world. Even though none of the nearly two million tons of fluorspar shipped from Marathon during the last 15 years came from a deposit in Texas, several occurrences of fluorite are known in southern Brewster County, Texas: the northern Mexico fluorspar province does not terminate abruptly at the Rio Grande. Deposits in Mariscal Mountain in Big Bend National Park are possibly equal in size and grade to deposits 5 to 10 miles southward across the Rio Grande in the San Vicente district. Potentially commercial deposits are known at several places in and around the Christmas Mountains (just outside the northwestern boundary of Big Bend National Park), and fluorite mineralization is widespread throughout the Terlingua quicksilver district. Cretaceous limestone formations which serve as host rocks for fluorspar deposits in northern Coahuila crop out extensively in Brewster County, Texas in the following areas: the Dove Mountain--Maravillas and Reagan Canyon country, on the flanks of the Marathon Dome, in the Sierra del Carmen--Santiago--Del Norte Range, in the Christmas Mountains--Corazones Peaks area, in the Terlingua quicksilver district, and in Mariscal Mountain in Big Bend National Park. But, in Brewster County, as in Coahuila, fluorspar deposits are found only in close proximity to rhyolite intrusions. The intrusive rocks in southeastern Brewster County are dominantly syenodioritic in composition and most of the intrusions north of the Christmas Mountains--Corazones Peaks area are trachytes and microsyenites.
Uranium in Texas, 1967
(University of Texas at Austin. Bureau of Economic Geology, 1967) Flawn, Peter Tyrell
The uranium industry, born in boom in the late 1940's and early 1950's, fell upon hard times after about a decade of lusty growth as anticipated private markets failed to develop on schedule and the United States Atomic Energy Commission cut back and stretched out its purchase program. Exploration for uranium in the United States came to a halt. Mills closed down or operated on reduced schedules as contracts expired. But in 1965 there were signs of change as more and more announcements of construction of nuclear reactors for generation of electric power appeared in the newspapers, and by 1966, the discouraged uranium salesman found doors opening rapidly and smiles on the faces of his potential customers. The hoped-for private-sector market for uranium had become a reality. By September 1, 1966, a total of 47 reactors were either in operation, under construction, or firmly committed in the United States; of the total, orders for or commitments for 32 were made since February of 1965. The industry considered this sharply rising curve, looked at the nuclear fuel requirements, appraised the known reserves of uranium ore, and literally sprang into action. In the first half of 1966, only about half a million feet of exploratory drilling was completed; twice this was scheduled for the second half of the year and a million and a half feet has been budgeted for 1967.
History of geology at the University of Texas
(University of Texas at Austin. Bureau of Economic Geology, 1967) Young, Keith, 1918-2004
This history of geology at The University of Texas was prepared for the dedication of the new Geology Building, November 1967. It is a brief history; many details have been omitted. The names of most graduates and some faculty will not be found. The mission was to summarize some important landmarks in Geology at The University of Texas and to describe the personalities and personal relationships that explain many of the decisions that have brought us to the present. I propose a toast to those who have made us what we are.----- Keith Young
Depositional systems in the Wilcox Group of Texas and their relationship to occurrence of oil and gas
(University of Texas at Austin. Bureau of Economic Geology, 1967) Fisher, W. L. (William Lawrence), 1932-; McGowen, J. H.
Regional investigation of the lower part of the Wilcox Group in Texas in outcrop and subsurface indicates seven principal depositional systems. These include: (1) Mt. Pleasant Fluvial System developed updip and in outcrop north of the Colorado River;(2) Rockdale Delta System, present primarily in subsurface, chiefly between the Guadalupe and Sabine Rivers; (3) Pendleton Lagoon-Bay System in outcrop and subsurface largely on the southern flank of the Sabine Uplift; (4) San Marcos Strandplain-Bay System, occurring in outcrop and subsurface mainly on the San Marcos Arch; (5) Cotulla Barrier Bar System in subsurface of South Texas; (6) Indio Bay-Lagoon System developed updip and in outcrop of South Texas; and (7) South Texas Shelf System, an extensive system entirely within subsurface of South Texas. The Rockdale Delta System, consisting of large lobate wedges of muds, sands, and carbonaceous deposits, is the thickest and most extensive of the lower Wilcox depositional systems. It grades updip to the thinner terrigenous facies of the Mt. Pleasant Fluvial System. Deposits of the Rockdale Delta System were the source of sediments redistributed by marine processes and deposited in laterally adjacent marine systems. Delineation of depositional systems and, more specifically, delineation of component facies of the various systems, permits establishment of regional oil and gas trends which show relationship of producing fields and distribution of potentially producing trends.
Glen Rose cycles and facies, Paluxy River Valley, Somervell County, Texas
(University of Texas at Austin. Bureau of Economic Geology, 1968) Nagle, J. Stewart (James Stewart), 1889-1952
Paleoenvironmental analysis of the alternating beds of the basal Cretaceous Glen Rose Formation in Central Texas indicates a cyclical alternation of subtidal through supratidal facies. These facies were reconstructed through detailed analysis of lithology, biota (including macrofauna, microfauna, ichnofauna, and macroflora), detrital shell dispersal, and primary sedimentary structures. Facies succession indicates that each cycle represents a subtidal to supratidal depositional regime transit; cycles are regressional, with the transgressional phase being poorly developed, if at all. This conclusion is in agreement with results of studies of the Holocene transgression, which reveal a regressional succession developed by progradation of shorelines. Some other formations show similar depositional regime transit cycles; hence the Glen Rose model may be widely applicable. Facies variations within and between cycles indicate (1) that there is no typical or ideal cycle, (2) that the cycles record successive sedimentation units within a marginal marine hypersaline lagoon or bay system, and (3) that depositional regime transit cycles have limited correlation value. Facies in the seven cycles in the lower Glen Rose, Paluxy Valley, include subtidal to supratidal flat deposits, marsh, flood plain, shoal patch reef, bay, marsh island, and shifting sand lobe deposits; the only typical aspect of the cycles is their general subtidal to supratidal succession. Mixed terrestrial, marginal marine, and marine faunas and floras within these facies tracts indicate that the lower Glen Rose in this area is a lagoonal or bay depositional system. Paucity of terrigenous elastics, abundance of evaporites, presence of serpulid-patch reefs, and relatively low diversity of faunas with an abundance of thick-shelled ostracods indicate that at least the earlier phases of the lagoonal system were hypersaline. Areal stratigraphic correlation of these depositional regime transit cycles is unwise because the cycles tend to proliferate downdip, and because units that could be used as key beds commonly are local in extent. These beds reflect similar depositional conditions which recur in homotaxial phases of different cycles; indeed potential key beds may change facies within a few miles, even when bed thickness remains nearly constant. Correlation by matching cyclesin sections less than a mile apart, however, is feasible. Several particulars are useful in recognizing position in the cycle. Burrow fillings change upwards from lime-mud to sparry calcite or dolomite--a reflection of diagenetic regime. Burrows with unlithified or partially indurated calcite mud and shells occur in subtidal sediments. Diagenetically modified burrows first appear in or above the zone of sorted and abraded shell, inferred to be the wave or beach zone. Diagenetic burrow modification is intrastratal; this plus the dense fabric with unaltered shells indicate early, soft sediment diagenesis. Paleoenvironmental evidence plus studies of the Recent support the idea that these diagenetic modifications are associated with exposure and solutional modification, dolomite by hypersalinity, sparry calcite by fresh water. Subtidal deposits contain articulated and unsorted shells, many in living position; nearshore wave zone or intertidal shells occur in beds of well-sorted and abraded detrital plates. Supratidal deposits abound in rollers or may contain abraded detrital plates in texturally inverted sediments. Supratidal marshes contain abundant remains of the plant Frenelopsis. Its tiny cells, thick epiderm, protected stomata, and poorly developed roots indicate it is a physiological xerophyte similar to Salicornia of present-day salt marshes.
Geometry and distribution of fluvial and deltaic sandstones (Pennsylvanian and Permian), North-Central Texas
(University of Texas at Austin. Bureau of Economic Geology, 1969) Brown, L. F. (Leonard Franklin), 1928-
Upper Pensylvanian and lower Permian rocks of the Eastern Shelf in North-central Texas are composed of 10 to 15 repetitive sequences including open shelf, deltaic, fluvial, and interdeltaic depositional systems. Sediments derived from the Ouachita Mountains and associated piedmont were transported westward across a narrow coastal plain. Fluvial and deltaic sandstone fac1es define a southwest paleoslopc of about 5 feet per mile. Sandstone facies are delta front sheets, distributary mouth bars, distributary and fluvial channels, and destructional bars. Sandstones displaying distributary patterns represent distal deposition in the upslope area. Belt sandstones, typified by uncommonly thick fluvial channel deposits, prograded far downslope. Composite patterns include distributary and belt sandstones representing complex progradational history. Rocks display one-half degree northwest regional dip; negative structure residuals outline a broad area within which 70 percent of the deltaic facies were deposited. Elongate sandstones are generally arranged parallel to paleoslope in vertically offset patterns controlled by differential compaction of fluvial and deltaic sands and interdistributary muds. Multistory sandstone bodies were deposited along narrow, structurally unstable belts which were periodically overloaded and later reoccupied by prograding deltas. Initial Cisco deltas followed a paleosurface grain controlled by underlying bank limestones; this orientation was maintained during deposition of 1,200 feet of Cisco strata. Each fluvial-deltaic system inherited its geometry from previous systems and, in turn, provided control for the next deltaic episode. Stratigraphic and structural mapping utilizing mud decompaction techniques confirms the roles played by compaction and structure in controlling the geometry of sandstone bodies.
Sulfur in West Texas, its geology and economics
(University of Texas at Austin. Bureau of Economic Geology, 1969) Zimmerman, James B.; Thomas, Eugene, 1904-
Sulfur, along with salt, coal, and limestone, is one of the basic raw materials of the chemical industry. A nation's per capita sulfur consumption is a reliable index to its chemical production and a rough index to its standard of living. Sulfur, with its many properties, has literally hundreds of uses; most is used in the manufacture of fertilizers, fibers, papers, pigments, pharmaceuticals, and explosives.Sulfur or brimstone is one of the oldest elements known to man. It was used more than 4,000 years ago in rituals of sacrifice and as a bleaching agent for cotton. The Chinese, around 500 B.C., used sulfur as an ingredient in gunpowder. Arabian alchemists are thought to have discovered sulfuric acid in the 8th Century while trying to convert sulfur to gold. Sulfur became commercially important in 1791 with the development of the Leblanc soda ash process in France (Ambrose, 1965, p. 901). The sulfuric acid industry, which began in the United States near the end of the 18th Century, now uses about 87 percent of the total production. Sulfur plays an increasingly vital role in American industry and agriculture. The 1966 sulfur shortage motivated are evaluation of West Texas geologic and economic potential for sulfur production and a re-examination of its lengthy but spasmodic sulfur history.
Virgil and lower Wolfcamp repetitive environments and the depositional model, North-central Texas
(University of Texas at Austin. Bureau of Economic Geology, 1969) Brown, L. F. (Leonard Franklin), 1928-
Virgil and lower Wolfcamp rocks on the Eastern Shelf in North-central Texas are composed of several intergradational depositional systems comprising 1,200 to 1,500 feet of off-lapping, predominantly terrigenous sediments. At least a dozen major and numerous minor repetitive sequences consist of superposed deposittional systems, composed of more or less homotaxial component facies. Rapidly shifting fluvial-delta sites and associated interdeltaic and open shelf environments on the slowly subsiding shelf were subjected to marine destruction, mud compaction subsidence, and marine transgression. Variations of the basic sequence in time and space resulted from shifting depositional systems. Pluvial variants are downslopes, and deltaic and interdeltaic variants are concentrated in intermediate areas. These facies tracts shifted irregularly southwestward during Virgil and Wolfcamp deposition as the average strandline migrated with westward shelf progradation. Westward pointing deltas locally extended subaerial environments far downslope. Delta sequences between bases of successive delta systems are diachronous and aperiodic as deltation irregularly reoccupied former delta sites. Sequences between bases of successive transgressive limestone facies are also interpreted to be aperiodic and diachronous, but bounding limestones display regional continuity. Delta and fluvial constructional facies represent relatively brief, discrete time intervals, while destructional, interdeltaic, and transgressive facies involved greater time resulting in complex chronology within sequences. The fluvial-deltaic model for Virgil and Lower Wolfcamp rocks make it unnecessary to invoke external cyclic control to explain these North-central Texas deposits. The self-regulating model can operate under continuous sediment supply and continuous but slow shelf subsidence. The model is based on fades relationships and processes rather than absolute scale and geometrical comparison with Recent models. The diachronous nature of fades required by the model and supported by stratigraphic evidence indicates that repetitive deposition was primarily governed by sedimentary processes active within the local basin.
Depositional systems in the Jackson Group of Texas: their relationship to oil, gas, and uranium
(University of Texas at Austin. Bureau of Economic Geology, 1970) Fisher, W. L. (William Lawrence), 1932-; Proctor, Jr., C.V.; Galloway, William E.; Nagle, J. Stewart (James Stewart), 1889-1952
Five main depositional systems of the Jackson Group in Texas are delineated through regional outcrop and subsurface investigation. Dominant element in the central and eastern Texas Gulf Basin is the Fayette fluvial-delta system (bounded by Guadalupe River on the south and Neches River on the east) consisting of dip-oriented, lobate wedges of sands, muds, and lignites. Vertical sequence in updip subsurface and outcrop grades upward from marine muds through delta facies into fluvial sands and muds, reflecting net regression and progradation of the system. Longshore drift of sediments from the delta system contributed to the South Texas strandplain-barrier bar system, consisting of strike-trending sand bodies interbedded with marine and lagoonal muds. Landward of the strandplain-barrier bar system and extending into outcrop is a lagoonal-coastal plain system consisting of muds, local lignites, and minor, dip-oriented channel sand units. Gulfward of the strike-trending strandplain system is the South Texas shelf system, formed of marine muds derived largely from the delta system to the northeast. Beneath the South Texas strandplain-barrier bar and Fayette delta systems and extending eastward into Louisiana and Mississippi is the Yazoo-Moodys Branch shelf system consisting of marine, fossiliferous muds and minor glauconitic marls. Texas Jackson delta and associated systems are comparable to depositional systems of other Eocene units (Lower Wilcox and Yegua) of the Gulf Basin as well as the Holocene Mississippi delta and related systems of the northwestern Gulf of Mexico. Delineation of depositional systems and component facies facilitates definition of significant mineral trends (oil, gas, lignite, and uranium) that show the relationship between existing and potential areas of production.
Mineral resources and conservation in Texas
(University of Texas at Austin. Bureau of Economic Geology, 1970) Flawn, Peter Tyrell
The conservation movement has grown enormously in strength and breadth during the last decade as a result of widespread concern about natural resources and the quality of the environment. The Federal leadership broadened the definition of conservation to applied ecology and thereby put a meaning into the word that went far beyond its original sense. Conservation now includes all of the physical, social, and legal problems attendant on use of the land. The inclusion of a wide variety of environmental problems under the umbrella of conservation caused a great deal of pushing and shoving of traditional "conservationists" to make way for the new "environmentalists." Broadening of the conservation movement to a total-environment movement has brought many new people into it--scientists, engineers, economists, geographers, and ecologists--people that are professionally concerned with the environment on a working-day basis.
Geological considerations in disposal of solid municipal wastes in Texas
(University of Texas at Austin. Bureau of Economic Geology, 1970) Flawn, Peter Tyrell; Leach, Carolyn H.; Turk, L. Jan
In the United States the average citizen produces 6 to 8 pounds of solid wastes per day--this includes his personal contribution plus his pro-rata share of industrial and agricultural wastes. A city of 200,000 to 300,000 people is faced with collecting, transporting, and disposing of about 400 tons to 500 tons of solid wastes every day. This is the amount produced by the residents and small businesses--it does not include the wastes from big industrial operations. Costs of solid waste disposal range from $10 to $30 per ton depending on local labor costs, the distance the material must be transported, and the costs of acquisition and operation of disposal sites. In Texas, cost of landfill operations alone averages $1.10 per ton (Gazda and Malina, 1969, p. 23). The practice of open burning of wastes at the disposal site has been discontinued in many areas because of air pollution control legislation. This increases the volume of material that must be buried. In some areas the volume of solid wastes is reduced by high-temperature incinerators prior to ultimate disposal, in others controlled burning of wastes produces by-product steam.
Resource capability units: their utility in land-and water-use management with examples from the Texas coastal zone
(University of Texas at Austin. Bureau of Economic Geology, 1971) Brown, L. F. (Leonard Franklin), 1928-; Fisher, W. L. (William Lawrence), 1932-; Erxleben, A. W.; McGowen, J. H.
A resource capability unit is an environmental entity--land, water, area of active process, or biota--defined in terms of the nature, degree of activity, or use it can sustain without losing an acceptable level of environmental quality. Units are established by recognizing elements of first-order environmental significance, whether dominantly physical, biologic, or chemical. These include (1) physical units (geologic substrate and soil units), where physical properties are of primary importance; (2) process units, such as beaches, washover channels, floodplains, escarpments, and dunes where active physical processes are dominant factors; (3) biologic units,such as reefs, marshes, swamps, and grassflats where biologic activity and habitation assume first-order significance; and (4) man-made units such as spoil heaps, dredged channels, canals, and made land where man's activity has resulted in important environmental modification. Capability of water systems is defined by the nature and distribution of sediment substrate, overall salinity patterns, circulation, tidal influence, depth variations, turbidity, fresh-water influx, distribution of biologic communities, and water chemistry. This report outlines (1) the nature of resource capability units, (2) the basic factors and properties exhibited by the units that define the limits of their use, and (3)the application of resource capability units to environmental management. Specific examples are shown for the 20,000 square miles of the Texas Coastal Zone, where a wide variety of resource units occur in an area of diverse human activities.
Cretaceous paleogeography: implications of endemic ammonite faunas
(University of Texas at Austin. Bureau of Economic Geology, 1972) Young, Keith, 1918-2004
Endemic ammonite faunas evolved from cosmopolitan faunas in a series of successive episodes over about 35 million years of the Cretaceous of the Gulf Coast of the United States. During basin-basin-margin tectonic adjustments the Cretaceous barrier reef was inundated or circumvented so that a cosmopolitan fauna entered the back-reef area. Gradual isolation of the fauna behind the barrier produced endemism. With the next basin adjustment the endemic fauna became extinct, and a new cosmopolitan fauna migrated into the back-reef area, likewise evolving into an endemic fauna in its turn. Six cosmopolitan-endemic cycles have been identified. Geological evidence suggests two or three additional cycles.
Mineral deposits in the West Chinati stock, Chinati Mountains, Presidio County, Texas
(University of Texas at Austin. Bureau of Economic Geology, 1972) McAnulty, William Noel, 1913-
The West Chinati stock, well exposed in San Antonio Canyon and immediately westward on slopes of the southwestern part of the Chinati Mountains, Presidio County, Texas, is a large stocklike body of porphyritic hornblende granite cut by numerous dikes and irregular-shaped plutons of rhyolite, rhyolite porphyry, microgranite, trachyte porphyry, diorite, and igneous breccia.Fissure veins developed in wide and long sheeted zones which strike E-W and N. 50" E. containpotentially commercial deposits of lead-zinc-silver fluorspar, minerals including galena (PbS), sphalerite (ZnS), argentite (Ag2S), cerargyrite (AgCl), and fluorite (CaF2). Minor amounts of chalcopyrite (CuFeS2) and oxidized copper minerals also occur in the fissure vein deposits. Marginal bodies of rhyolite, rhyolite porphyry, and trachyte porphyry contain disseminated copper mineralization and possibly host commercial porphyry-type copper deposits.
Depositional systems and oil-gas reservoirs in the Queen City Formation (Eocene), Texas
(University of Texas at Austin. Bureau of Economic Geology, 1972) Guevara, Edgar H.; García, Roberto
Regional surface and subsurface studies indicate that thick deltaic (Queen City Formation) and thin shelf (Reklaw and Weches Formations) sequences compose the stratigraphic interval between the top of the Carrizo Sand and the base of the Sparta Formation. In East Texas, the Queen City Formation accumulated as part of a high-constructive, lobate delta system; and in South Texas, as part of a high-destructive, wave-dominated delta system. In South Texas, principal facies are meanderbelt sand, lagoonal mud, stacked coastal barriers, and prodelta shelf mud facies. In East Texas, delta plain, delta front, and prodelta facies are dominant; and in Central Texas, the principal facies are strandplain sands originated by southwestward longshore drift of sediments from the high-constructive delta system. Facies distribution, composition, and size of the deltas in East Texas are similar to lobes of the Holocene high-constructive Mississippi delta system and to ancient deltas in the lower part of the Wilcox and m the Jackson Groups of the Gulf Coast Basin. Deltaic sediments of South Texas are comparable to Pleistocene high-destructive, wave-dominated facies on the Surinam coast, to the Holocene Rhone delta system, and to ancient deltas in the upper part of the Wilcox Group. Queen City deltas prograded gulfward over shelf muds and glauconites of the Reklaw Formation; they are overlain by comparable shelf facies of the Weches Formation. In East Texas, deltaic facies wedge out eastward. Terrigenous elastics of the high-destructive deltas extend southward into Mexico. Hydrocarbons are produced from thin strike-oriented sands downdip from the belt of maximum sand thickness of the high-destructive deltas in South Texas; only a minor amount of oil and gas has been obtained from delta front and distributary channel sands of the high-constructive deltas in East Texas.

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