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Quaternary Stratigraphy and Paleoenvironments of the Texas Rolling Plains

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Quaternary Stratigraphy and Paleoenvironments of the Texas Rolling Plains Quaternary stratigraphy and paleoenvironments of the Texas Rolling Plains S. CHRISTOPHER CARAN Department of Geological Sciences, The University of Texas at Austin, Austin, Texas 78712 ROBERT W. BAUMGARDNER, JR. Bureau of Economic Geology, The University of Texas at Austin, BoxX, Austin, Texas 78713-7508 ABSTRACT assemblage of upper middle(?) Pleistocene or cado) to the west and the moderately dissected, upper Pleistocene to Holocene lithofacies herein mostly externally drained Rolling Plains to the The Lingos Formation (new) comprises a designated the "Lingos Formation." The Lingos east. South of the valley of the Little Red River, thick sequence of Quaternary alluvial-fan, Formation is part of the Paducah Group (new), segments of the escarpment are nearly vertical, lacustrine, fluvial, and eolian deposits. These which comprises several named Quaternary and local relief exceeds 150 m. Geologic units strata cover 9,250 km2 of the western Rolling formations and unnamed deposits, as shown in composing this part of the escarpment are, from Plains of Texas. The Lingos Formation is Figure 1. Recent field investigations focused on top to bottom, the Tertiary Ogallala Formation, part of the newly designated Paducah Group, parts of Briscoe, Hall, Floyd, and Motley Coun- Triassic Dockum Group, and Permian Quar- which includes three previously recognized ties where the Lingos Formation is particularly termaster Formation (Fig. 2). In much of the middle to upper Pleistocene formations in well exposed (Figs. 1 and 2). More than 100 region, siltstones, sandstones, and conglomerates addition to the Lingos Formation and several outcrops and more than 300 drillers' logs of of the Ogallala are heavily cemented with cal- unnamed or uncorrelated stratigraphie units. water wells in this area form the basis for this cium carbonate. Resistant calcretes "cap" the es- The origin of these formations is closely asso- description of the Lingos. In addition, a water carpment, giving rise to the popular name ciated with westward retreat of the Caprock well penetrating a thick Quaternary section and "caprock." Escarpment and with subsidence resulting subjacent Permian red beds was logged during The Quaternary Lingos Formation extends as from regional intrastratal dissolution of Per- drilling and cuttings were sampled. Data from much as 480 km along and 80 km eastward mian evaporites. Dissolution produced subsi- outcrops, wells, and selected laboratory analyses from the Caprock Escarpment (Fig. 1). Origi- dence basins, which gradually filled with define the lateral extent, continuity, thickness, nally, the Lingos terrane may have exceeded sediment derived from the retreating escarp- age, and stratigraphic variability of Lingos strata. 26,000 km2, based on interpolation among ment. Lakes occupied at least some of the Map representation of the regional Quaternary remnants of the formation. Holocene erosion subsidence basins and were sustained by terrane (Fig. 1) is conservative; Lingos deposits has reduced the area covered by the Lingos to emergent ground water rather than by sur- may be more continuous than indicated and approximately 9,250 km2. Because of their lat- ficial inflow. Stratigraphie relations and may extend farther east, north, and south. eral extent and thickness, as well as their per- paleofaunas document significant Quaternary Objectives of this study are to characterize the meability, Lingos deposits constitute a signifi- environmental change linked to subsidence, newly recognized Lingos Formation and Pa- cant fresh-water aquifer, the principal source of stream incision, and climatic variation. ducah Group and their relation to regional and water for domestic and agricultural use Chronologic control is afforded by diagnostic local subsidence, retreat of the Caprock Es- throughout the western Rolling Plains. vertebrate faunas (Rancholabrean and Holo- carpment, and changes in surface- and ground- cene), Paleoindian through historic archeo- water regimes. The study employs a variety of PREVIOUS INVESTIGATIONS logical remains, and more than 50 radiocar- chronologic indicators, including diagnostic pa- bon ages. On the basis of these data, leofaunas and cultural materials, as well as radi- Stratigraphic Studies deposition of the Lingos Formation spanned ocarbon ages. These indicators provide a tem- the period from less than 300 ka ago to the poral framework for reconstructing landscape Several workers have described aspects of the present. The depositional history of the Lin- evolution. Pleistocene and Holocene stratigraphy of the re- gos Formation provides a model for the gion east of the High Plains, including Cummins origin of the Paducah Group as a whole, and LOCATION (1893), Frye and Leonard (1957, 1963), Van for Quaternary landscape evolution through- Siclen (1957), Stricklin (1961), Dalquest (1962, out the Rolling Plains. The study area encompasses much of the 1964a, 1964b, 1965, 1986), Hibbard and Dal- Rolling Plains, particularly that part adjacent to quest (1966, 1973), Gustavson and Holliday INTRODUCTION the Caprock Escarpment (Fig. 1). The escarp- (1985), Baumgardner and Caran (1986a, ment forms a drainage divide and physiographic 1986b), Caran and Baumgardner (1984, 1986a, Spreading eastward from the Caprock Es- boundary between the flat, mostly internally 1986b, 1986c, 1988, 1990), and Caran (1990). carpment in northwestern Texas is a complex drained Southern High Plains (or Llano Esta- Frye and Leonard (1957, 1963) and Dalquest Additional material for this article (figure and table) is available free of charge from the GSA Data Repository by requesting Supplementary Data 9011 from the GSA Documents Secretary. Geological Society of America Bulletin, v. 102, p. 768-785, 10 figs., 2 tables, June 1990. 768 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/102/6/768/3380965/i0016-7606-102-6-768.pdf by guest on 28 September 2021 Figure 1. Areal extent of the Quaternary Lingos For- mation (new) and other for- mations composing the Pad- ucah Group (new) of the Texas Roiling Plains. Adapt- ed from geologic maps and water-well records com- piled by George and Foster (1942), Dalquest (1962, 1964b, 1965), Eifler (1967, 1968, 1974, 1975), Brown and others (1972), Popkin (1973), Smith (1973), Kier and others (1976), Havens (1977), Hentz and Brown (1987), and Caran and Baum- gardner (1988, 1990). Addi- tional mapping in selected areas. 32°N • EXPLANATION Mapped extent of these deposits includes areas of fluvial and dunal 3 •Xl'lY; Qg • <D sediments of presumed Holocene age. Qgc* Boundaries dashed where uncertain. a. Quaternary Lingos Fm.(new) CD Extensive Neogene and Quaternary si Groesbeck Fm. O deposits of the Southern High Plains o Good Creek Fm. not shown here. "•O CL > •Qu- ® Exposure of Lava Creek B D volcanic ash in Kent Co., 'Os! a 0) Texas (Izett and Wilcox, 1982). Quaternary unnamed =o> Other exposures of this ash Seymour Fm. O not shown here. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/102/6/768/3380965/i0016-7606-102-6-768.pdf by guest on 28 September 2021 770 CARAN AND BAUMGARDNER EXPLANATION H ] H Channel and terrace deposits £¡9 Site mentioned in text and/or {| | Lingos Formation sampled for radiocarbon dating Blair water well Blackwater Draw Formation Tertiary ¡Sgi] Ogallala Formation Triassic Dockum Group Permian |;; • ] Quartermaster Formation and Whltehorse Sandstone 5 mi 8 km Figure 2. Geologic map of the type area of the Lingos Formation and surrounding region. Map is based on Eifler (1968) but has been revised extensively, particularly with regard to Quaternary deposits. Location of area is shown in Figure 1. Localities discussed in text are marked by letters as follows: B, Lake Theo archeological site; L, Smith farm; M, Blair farm; N, Edwards farm. (Results of radiocarbon analyses for these and other sites marked by letters are included in information available from GSA Data Repository.) (1964a) were the first to discuss the Quaternary and did not recognize their considerable lateral to the Miocene-Pliocene Ogallala Formation, its strata and paleofauna of the present study area; extent and complex origin. calcareous caprock (Pliocene, at least in part), however, these investigations did not provide Most early work in the Rolling Plains was and the middle Pleistocene Seymour Formation detailed stratigraphie descriptions or geologic conducted outside the Lingos terrane. Van (his "intermediate division" of the Pleistocene mapping. As a consequence, Frye and Leonard Siclen (1957) examined the extreme southern section). The Seymour was informally described interpreted these deposits as local fluvial terraces Rolling Plains. He devoted most of his attention and named by Cummins (1893, p. 181). Strick- Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/102/6/768/3380965/i0016-7606-102-6-768.pdf by guest on 28 September 2021 QUATERNARY TEXAS ROLLING PLAINS 771 Northwestern and North-Central Texas EXPLANATION ©JZ o Fluvial, alluvial-fan, colluvial,and o O O 4) Western and Northern Eastern and Southern CL o x: eolian deposits; generally Ld CL U i < Rolling Plains Rolling Plains continuous over large areas \Unnamed lacustrine Lacustrine and palustrine deposits; (cenote) and upper Unnamed fluvial, generally deposited within discrete (fluvial and eo- colluvial, and palustrine basins x 9Ï I¡an deposits) eolian deposits deposits 10 Ka • ? XX? Volcanic ash, lateral extent uncer- Ka- tain; name and age based on Izett and Wilcox (1982) Unnamed fluvial
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