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 •
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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-
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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 Groesbeck and eolian depos- Formation* PRINCIPAL MAGNETIC POLARITY its* (Lingos (Dalquest, Formation?) in 1965) + = Normal northern and — = Reversed southern parts of ?~50 Ka? region (see fig. I) CONTACTS OR TEMPORAL lower (alluvial- BOUNDARIES fan and fluvial Good Creek Formation* deposits or 128- ( Dalquest, J Approximate age Ka saprolite 1962) "I (local) Variable age -300- 1 Ka Unnamed fluvial, alluvial-fan, and Ka= 1000 yr before present eolian deposits Ma= 1,000,000 yr before present between Lingos
and Seymour ter- 102° IOO°W rains;* includes + + + + ï fossiliferous fluvial deposits in Chil- dress ( Dalquest, 1964 b) and Stone- wall Counties ( E.L. Lava Creek B Lundelius, Jr., ?XXX? 620 Ka personal commun- Seymour Formation* ication, 1986) (Hibbard and Dal- quest, 1966, 1973-, 736 Izett and Wilcox, - Ka-
Figure 3. Correlation of Quaternary deposits of the Rolling Plains (adapted from Caran, 1990).
lin (1961) briefly summarized the lithology of Seymour, Good Creek, and Groesbeck Forma- Pleistocene Meade Formation of central and the Seymour, which includes an interbedded tions appear to be genetically similar to the Lin- southwestern Kansas. The Lingos Formation is volcanic ash. Hibbard and Dalquest (1966, gos Formation and are included in the new actually much younger than the Meade, but the 1973) designated the Seymour Formation type Paducah Group, along with the Lingos Forma- origins of these formations are comparable in section, described its paleofauna, evaluated the tion and several unnamed lithostratigraphic many other respects. Subsidence resulting from age of the fauna, and confirmed the presence of units (Fig. 3). intrastratal dissolution of Permian evaporites is the Lava Creek B volcanic ash, formerly known widespread in the western Rolling Plains (Gus- as the "Pearlette Type O" (Izett, 1981; Izett and Chronologic Studies tavson and others, 1982). Subsidence localized Wilcox, 1982; Simpkins and Baumgardner, and enhanced Lingos sedimentation. Similarly, 1982). Dalquest (1962, 1965) named two up- Frye and Leonard (1957, 1963) sought to the Meade Formation "fill(s) deep valleys cut per Pleistocene formations, the Good Creek infer the age of deposits now designated the Lin- below the Ogallala surface or fill(s) solution- and Groesbeck, in Foard and Hardeman Coun- gos Formation. These investigators considered subsidence or down-faulted areas" (Frye and ties, respectively. These units lie approximately most of the Quaternary deposits of the Rolling others, 1948, p. 522). Lingos deposition, like 70 km east of the Lingos outcrop (Fig. 1). The Plains of Texas to be coeval with the middle that of the Meade, clearly postdated regional
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EXPLANATION 2 mi 0 2 km Tertiary • Water well with driller's log Contour interval 20 ft Ogallala !;TO! Formation Paleochannel or closed depression Triassic Elevation of Dockum ,0 top of Permian '"Mr] Group red beds (ft)
Permian
Quartermaster Pq: Formation
Figure 4. Structure-contour and isopachous maps of part of the western Rolling Plains, based on data from wells and outcrops. Most of this area lies south of that shown in Figure 2. Where wells and exposures are widely separated, contours are correspondingly generalized, (a) Structure-contour map of the Permian subcrop underlying the Quaternary Lingos Formation, (b) Isopachous map of the Quaternary Lingos Formation. The formation is thickest where underlying Permian strata have subsided (for example, 2 km east of Flomot) or were eroded during or prior to deposition of Lingos sediments (for example, along the northwestern border of Motley County). Lingos deposits are thinnest over high erosional remnants of the Triassic subcrop (for example, 3 km northwest of Flomot) and where existing streams have stripped away much of the Lingos sediment (for example, along Los Lingos and Quitaque Creeks).
stripping of the Ogallala Formation, which re- Lava Creek B ash (Naeser and others, 1973; Pleistocene gravel deposits in southwestern sulted from westward erosional retreat of the Izett and Wilcox, 1982), as does the Seymour Childress County (Fig. 1). On the basis of Caprock Escarpment (Gustavson and others, Formation of the Paducah Group (Hibbard and mammoth remains and the absence of bison 1981). Dalquest, 1966, 1973) (Fig. 3). Therefore, the material, Dalquest (1964b) concluded that the The Meade Formation contains an Irving- Seymour is roughly isochronous with the fauna in the Childress County deposits is Irving- tonian land-mammal fauna and the 620-ka Meade. The Seymour may also be coeval with tonian. In contrast, the Lingos Formation con-
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Quaternary Triassic • Water well with ~ V - driller's log ~ Lingos Oockum Ql / / / / / / Formation Group / / / / / / Thick 2 mi Lingos ////// section O 2 km Tertiary Permian ^ Thin Lingos Contour interval 20 ft Quartermaster Ogallala Pq.; \\\\\\ section ijTol Formation Formation y Thickness ,Q0 of Lingos Figure 4. (Continued). / Formation (ft)
tains a Rancholabrean fauna, does not include Geomorphic, tephrochronologic, and faunal GEOLOGIC SETTING OF THE volcanic ash deposits, and is stratigraphically iso- evidence reported by previous investigators in- LINGOS FORMATION lated from ash-bearing units. Izett and Wilcox dicates that the Seymour Formation and un- (1982) reported the presence of Lava Creek B named Childress County gravels predate the Regional Geomorphic Surface volcanic ash in Kent County, Texas (their local- Lingos Formation (Figs. 1 and 3). The Seymour ity Texas 15), which lies within the Lingos ter- is the easternmost and oldest of the Paducah The western Rolling Plains are characterized rane (Fig. 1). At this site, the bed of ash directly Group formations, whereas the Lingos is the by a flat to moderately rolling surface that is overlies Permian Whitehorse Sandstone and is westernmost and youngest. Stratigraphie units of continuous except where dissected by streams jointed and downwarped. Unjointed, horizon- intermediate age lie between the Seymour and (Fig. 2). Earlier geologic maps show the Per- tally bedded gravels of the lower Lingos Forma- Lingos. Formations composing the Paducah mian Quartermaster Formation cropping out tion unconformably overlie the Lava Creek B Group appear to have been deposited sequen- over most of this low-relief area (Eifler, 1967, ash and clearly postdate it by an undetermined tially, from east to west, as the Caprock 1968), which implies that the Rolling Plains sur- period. Escarpment retreated westward. face formed by planar degradation to a low-
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gradient pediment. Field mapping during the flowing streams. At their western (upslope) uncertain but probably are related to Holocene present study, however, has shown that most of edge, the deposits surround, but do not com- or late Pleistocene spring sapping. Spring sap- the area is underlain by thick Quaternary depos- pletely bury, a few isolated remnants of Permian ping is caused by discharge from the Ogallala its. Rather than being an erosional landform, the and Triassic bedrock projecting above the Roll- Formation, the major aquifer of the Southern geomorphic surface of the western Rolling ing Plains surface. Bedrock also crops out within High Plains. Gustavson (1983) and Osterkamp Plains developed by net aggradation of the Lin- the Lingos terrane in stream channels from (1987) concluded that spring sapping has en- gos Formation. which the Lingos was stripped by erosion as the hanced retreat of the Caprock Escarpment. Lingos deposits form a broad terrigenous clas- modern drainage network became entrenched. tic apron along the Caprock Escarpment. The Major modern drainage divides are oriented Effect of Permian Evaporite Dissolution eastward to southeastward slope of the Rolling normal to the escarpment, and most are capped on Lingos Deposition Plains surface ranges from approximately 15 with Lingos deposits, which indicates that much m/km near the escarpment to 7.5 m/km near of the Quaternary sedimentary complex pre- The Rolling Plains is underlain by the the toe of the Lingos sedimentary apron to the dates the present channel system (Figs. 1 and 2). westward-dipping eastern margin of the buried east. Eolian sediment accumulated on the Roll- Modern channels cut into the Lingos Formation, Palo Duro structural basin. In the Palo Duro ing Plains during most of the late Holocene, and terrace deposits are inset against the older Basin, aggregate thickness of Permian evapo- forming a smooth, continuous geomorphic Lingos strata. rites, primarily halite and anhydrite/gypsum, surface. Most of the Lingos outliers are detached from exceeds 1 km. Major tectonic events in this basin Yet today, the Lingos Formation and its asso- the Caprock Escarpment (Figs. 1 and 2). The occurred during the late Paleozoic, although ciated geomorphic surface are discontinuous head of the Lingos sediment apron has been epeirogenic uplift and limited differential base- along strike. The formerly continuous Lingos stripped in all but a few areas, even though no ment deformation recurred during the Cenozoic Formation has been dissected, creating outliers major streams parallel the escarpment. The pre- Era (Budnik, 1987). In addition to its long his- separated by eastward- and southeastward- cise mechanism and timing of detachment are tory of gradual, relatively minor tectonic distur-
West East
Caprock Escarpment Ogallala • Rolling Plains
Dockum Dewey Lake
2000- -600
1000- -300
QUATERNARY • Esa Lingos Formation TERTIARY/QUATERNARY 213 Ogallala and Blackwater Draw Fms. TRIASSIC I'/-' yl Dockum Group PERMIAN Mudstone Milla Interbd. mudstone and anhydrite/gypsum Datum mean sea level _ Interbedded halite and mudstone Geophysical logs1 gamma ray =l=d Interbd. carbonate and anhydrite/gypsum
* Top of halite dissolution zone
Figure 5. Structural cross section through the Caprock Escarpment and western Rolling Plains. Line of section is shown in inset map. Note that depth of the dissolution zone increases eastward, where prolonged dissolution has removed halite from shallow Permian formations, allowing penetration of deeper evaporites.
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bance, much of the Palo Duro Basin beneath the composite of several local sections exposed The present extent of this basal Lingos lithofa- western Rolling Plains has undergone regional along the gully, which extends approximately cies is extremely limited, however. Stratigraphy subsidence throughout the Quaternary Period, 1.1 km northward from Los Lingos Creek of the Lingos Formation and its principal litho- owing to interstratal dissolution of Permian (Red River drainage basin) to an unnumbered facies at the composite type section are summa- evaporites. county road. The Lingos Formation was named rized in Table 1. During most of the Pleistocene, updip parts of after Los Lingos Creek. Coordinates of the halite beds in the Palo Duro Basin were overlain northernmost local section in the Lingos type Relation to Subsidence by Permian mudstone aquitards. Denudation area are latitude 34°20'10.5"N, longitude reduced the thickness of these mudstones, facili- 101°06'43.1"W (U.S. Geological Survey, Qui- Active, recently active, and long inactive sub- tating ground-water infiltration and dissolution taque, Texas, 7.5' topographic map, 1967). This sidence features are common in the Rolling of evaporites. Dissolution caused surficial subsi- site is approximately 6 km along a bearing of Plains. Most of these features are small sinkholes dence and a rapid decline in local base levels. S56°W from the intersection of Texas Highway less than 100 m in diameter, but some are subsi- This process probably accelerated erosion and 86 and Farm-to-Market Road 1065 in Quitaque dence basins and troughs a few kilometers long. retreat of the Caprock Escarpment, thereby in- (Fig. 2). The Smith farm is several kilometers closer to creasing sediment supply. Eastward-transported The composite type section of Quaternary the Caprock Escarpment than are the sinkholes sediment was deposited in the zone of subsi- deposits cropping out in the gully is at least 47 m studied by Gustavson and others (1982), but dence, creating locally thick Lingos deposits. thick (Fig. 7, Table 1). Most local sections in the well within the zone of salt dissolution along the Detailed surface and subsurface mapping has type area include multiple erosion surfaces, indi- margin of the Southern High Plains. Effects of disclosed numerous basinal depressions filled cating partial truncation of these sections. The subsidence are clearly evident at the Smith farm with Quaternary sediment (Fig. 4). Karstic sub- locus of local deposition was the center of site. sidence was contemporaneous with deposition a subsidence basin that is only partly exhumed The Lingos composite type section includes in at least some basins. Quaternary deposits as and may contain a more complete section lacustrine deposits partly filling a closed struc- thick as 76 m (250 ft) occupy some low areas on (Fig. 6). Therefore, maximum Lingos thickness tural depression. Some of these deposits are this paleosurface, although 30 to 50 m (100 to at the Smith farm site may exceed the aggregate tilted and faulted, and beds thicken across some 160 ft) maximum thicknesses are more charac- thickness of exposed strata. faults. This evidence supports the conclusion teristic (Fig. 4b). A structural cross section (Fig. that subsidence created this lacustrine basin and 5) and an isopach map of Lingos strata (Fig. 4b) Permian Subcrop that subsidence continued intermittently during indicate that these deposits blanket an uneven and after infilling of the small lake. These inter- paleosurface. The Permian Quartermaster Formation, pretations are based on the following observa- Subsidence was widespread in Pleistocene which is the outcrop equivalent of the subsur- tions. (1) The lacustrine sequence overlies and early Holocene time. Moist climate during face Dewey Lake Formation (West Texas Geo- locally faulted and downwarped beds of sand the late Pleistocene turned sinkholes and subsi- logical Society, 1976, p. 245) (Fig. 5), is and gravel (Figs. 8a and 8b); (2) laminated la- dence basins into ponds and lakes, the largest of exposed in the floor and walls of the Smith farm custrine sediments at the basin margins dip which probably received phreatic discharge. gully near its confluence with Los Lingos Creek radially inward toward the center of the basin Comparatively dry regional climatic conditions (Fig. 6). Locally, the Quatermaster Formation (Fig. 8c); (3) dip increases downward through throughout the middle and late Holocene consists of thin-bedded siltstone and claystone the lacustrine section (Fig. 8c); and (4) lacus- (Caran and others, 1985; Neck, 1987) may have red beds. These Permian mudstones are rela- trine deposits are overlain by nearly concordant limited infiltration, ground-water movement, tively impermeable, causing calcium carbonate but less steeply dipping beds, including a paleo- and resulting dissolution-driven subsidence, al- to precipitate from ground water in the supeija- sol only 1,000 yr old. Furthermore, deflection of though these processes have continued to the cent Lingos gravels. In many outcrops, the base topographic contours over the lacustrine fill in- present. of the Lingos Formation is well cemented, form- dicates possible continuing subsidence at this site Gustavson and others (1982) recognized ex- ing a resistant calcrete. (Fig. 6). tensive modern karstic subsidence in the Rolling Plains, particularly in Hall and Briscoe Counties. Composite Type Section CHRONOLOGIC CONTROL Sinkholes and broad low-relief basins form as evaporites dissolve 150 to 240 m beneath the Although the Quaternary sequence in the Caran and Baumgardner (1986a) compiled surface (Gustavson and others, 1982). Unsatu- Lingos type area is complex, lithology and stra- and evaluated more than 50 radiocarbon age rated ground water within the Lingos deposits tigraphy of the type Lingos strata are representa- determinations based on samples collected in the may accelerate dissolution of subjacent Permian tive of local sections throughout the region. The Lingos Formation study area. Collecting sites' evaporites. Lingos Formation type section has been divided are described by Johnson and others (1982). informally into 22 lithostratigraphic units repre- Baumgardner and Caran (1986a, 1986b), Caran LINGOS FORMATION TYPE AREA: senting a variety of depositional environments and Baumgardner (1984, 1986b, 1986c, 1988, D. L. SMITH FARM, (Fig. 7). Individual units within the composite 1990), and Dalquest (1986). Reliable ages range BRISCOE COUNTY, TEXAS type section cannot be reliably traced outside the from 23,255 ± 2,335 yr to less than 1,000 yr. type area; however, these units define three Most of the radiocarbon analyses were per- The type area of the Lingos Formation is a major lithofacies that are correlative with most local sections. A fourth characteristic lithofacies, deep gully along the eastern boundary of the 1 D. L. Smith farm (also known as the Lazy J consisting of saprolites and slope-wash deposits, Detailed information about radiocarbon samples and sampling sites is available free of charge by re- Ranch) near Quitaque, Briscoe County, Texas crops out at the Smith farm and at a few other questing Supplementary Data 9011 from the GSA (Fig. 2, site L, and Fig. 6). The type section is a sites, always directly overlying Permian strata. Documents Secretary.
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mm Quaternary alluvium (modern) [m Quaternary Lingos Formation Permian Quartermaster Formation
j5 Strike and dip of bed 70 Joint (inclined) 7 Joint (vertical) _¡65 Normal fault showing dip of fault plane "Normal" fault (thrust fault, over- turned, barb on original upper plate), present dip of fault plane Fence Elevation datum
All contours in feet above mean sea level referenced to elevation datum shown and to additional points outside the map area.
BRISCOE COUNTY
Silverton
Area of Quitaque this figure
Topography by photogrammetric methods from aerial photographs taken February 14, 1979 (USDA 173-3 and 178-4).
500 1000fj t 100 200 300m
Contour interval variable'- 2 ft with 10-ft index contours; only 10-ft index contours shown in areas of relatively high relief.
Figure 6. Geologic map of the Lingos Formation type area, D. L. Smith farm, Briscoe County, Texas. Note deflections of topographic contours, particularly from 2,610 to 2,618 ft (796 to 798 m), which indicate that subsidence has affected local topography.
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TABLE I. SUMMARY OF LINGOS FORMATION STRATIGRAPHY IN TYPE AREA, BRISCOE COUNTY, TEXAS Areal geologic mapping, paleoecological inter- pretations, and numerous radiocarbon ages sup- Thickness Sedimentary/ Depositions! (m) pedogenic setting port the stratigraphic studies and help to structure constrain the model of Lingos deposition.
Upper Lingos Formation Throughout the late Quaternary, the variety, 19-22 Tabular eolian Silty, sandy Interfiuve Eolian deposit (22); stability, and regional distribution of deposi- cross-beds (22)*; clay to (22); truncated pedogenic B silty sand fluvial paleosol (21); tional environments were strongly influenced by horizon with channels through-flowing subsidence and by climatic changes. These en- moderate soil (19-21) drainage (19 20); structure (21) swale formed by vironments are represented by three principal downwarping (20) —Erosiona! unconformity— lithostratigraphic units: (1) lower Lingos allu-
Middle Lingos Formation vial-fan deposits of sand and gravel and local 13-18 Laminae; Slightly Perennial Beds dip toward saprolites and slope-wash deposits (composite secondary silty clay; lake basin center 16°; carbonate moderately (13-16); joints and faults; type section units 1-7); (2) middle Lingos lenses at interunit sapropelic ephemeral ostracodes aquatic of calcareous, fossiliferous, lacustrine clay (units contacts (16); lake (17, 18) and riparian calcareous mollusks; algae 8-18); and (3) upper Lingos sheet and channel marl (14, 15) [Chora) (14, 15) deposits of eolian silts and fluvial sands and Thin beds; Sand; Seasonal Beds, thicken lenses of clayey silt; lake toward basin center; gravels (units 19-22) (Fig. 9). sediment; silty clay joints; dip soft-sediment increases downward deformation to 22°; mollusks, Lower Lingos Formation: (9, 10) toot traces (12) Alluvial-Fan Deposits Lower Lingos Formation 2-7 Beds thicken Mostly medium Fluvial Deposition across faults sand and channels enhanced Across most of the region, the lowermost (7); tabular and gravel, minor by karstic trough cross-beds silt and clay; subsidence; stratigraphic component of the Lingos Forma- (2- 4, 6, 7); boulders locally faulted upward-fining (2.3) and jointed; tion consists of thick, laterally extensive beds of (2, 4); gravel downwarped sand and gravel dominated by lithoclasts of imbricated beds (7) (2. 3) Ogallala calcrete. These coarse-grained deposits
—Erosiona! unconformity- rest unconformably on Permian, Triassic, and
Laminae; Clayey silt; Weathered Weak pedogenesis; locally, Tertiary strata. Large-scale sedimentary thin lenses of uncommon in place vertical rhizocon- sand and gravel gravel lenses and locally cretions; bedding structures and the geometry and lithology of the slope washed thinner than in lower Lingos indicate primary paleotransport Permian bedrock Total 47 from the west. Evidently, most of the coarse detritus composing this part of the formation *Unit numbers refer to Figure 7. was transported by braided and meandering channels of broad alluvial-fan systems similar to those described by Miall (1978) and Galloway formed on concentrations of noncarbonate or- 1982; Caran and others, 1985). There, dismem- (1981). These systems originated at the Caprock ganic materials from buried soils and lacustrine bered skeletons of extinct Bison antiquus are as- Escarpment (Fig. 10a), and sediment was con- deposits. Ages were adjusted for 513C values sociated with Folsom and Plainview lithic veyed from this proximal source as the escarp- where possible. artifacts in upper Lingos deposits. These and ment retreated westward. Regional subsidence Fossil and archeological remains within the other chronostratigraphic indicators corroborate probably accelerated retreat of the escarpment Lingos Formation provide additional chrono- radiocarbon ages from the Lake Theo site, by continually lowering base level, causing logic control. A Rancholabrean fauna is present which range from approximately 12 to 1 ka. much of the resulting detritus to be trapped near at the Edwards farm (Fig. 2, site N), type area of Radiocarbon ages and stratigraphic evidence its source. The alluvial fans coalesced laterally, the Quitaque local fauna (Dalquest, 1964b, from several sites indicate that the Lingos For- eventually forming a broad bajada (Fig. 10b). 1986; Caran and Baumgardner, 1986b), and at a mation may be diachronous, decreasing in age Deposition of the lower Lingos Formation is few other localities. Rancholabrean faunas in to the west, but its Rancholabrean fauna and analogous to that of other parts of the Paducah this region probably are younger than 300 ka lack of volcanic ash beds show that the Lingos Group, particularly the Seymour Formation (late middle to late Pleistocene) (Lundelius and Formation probably is no older than late mid- (Menzer and Slaughter, 1971, their Fig. 2). others, 1987). Recent studies (Johnson and oth- dled) or late Pleistocene. Seymour bajadas accumulated along the retreat- ers, 1982; Caran and others, 1985; Neck, 1987), ing edge of an ancestral Caprock Escarpment when it lay much farther east. Thus, although supported by a variety of chronometric data, DEPOSITIONAL HISTORY OF THE most of the Seymour and lower Lingos sediment show that local molluscan faunas previously LINGOS FORMATION thought to be as old as middle Pleistocene (Frye was transported eastward, or normal to regional strike, fan deposits in aggregate were continuous and Leonard, 1957, 1963) are, in fact, early to Data from numerous outcrops and well logs along strike. middle Holocene. Archeological materials have form the basis for a regional depositional model been recovered at the Lake Theo bison- of the Lingos Formation (Fig. 9). Detailed stud- The lower Lingos Formation is as much as 40 butchering site (Fig. 2, site B), for which there is ies were conducted at sections discussed by m thick where it fills lows on the irregular Per- a detailed radiocarbon chronology (Harrison Baumgardner and Caran (1986a, 1986b) and mian subcrop. This paleosurface was shaped by and Killen, 1978, 1986; Johnson and others, Caran and Baumgardner (1984, 1986b, 1986c). erosion and subsidence. Subsidence was pene-
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Structure Texture Color* Unit l4C age, year b.p. (sample number); remarks 7.5yr4/4 22 5YR VS 1 ± 6 Faulted locally V//7//Ì 5yrV3 2i .000 70(TX4898) 75yr3a'_ — 2,970±70(TX4899)
5 YR3/34 > ******k 5
-4 5YR5/a- I I04 5 YRS/6 19 Major unconformity 7 7.5 YR /- _ (highly irregular) l08 IOYR6/2 I8 15,110±500(Beta 9607) - 11,625±1,000(Beta 9606), l2
24- Unconformity — highly irregular
I20- 3 Faulted locally
32- 124
36-. 2 Faulted locally l0YR7/z 15 18,665+1,355(Beta 9605) Contains mega- ioyr7/2 I4 23,255±2,335(Beta 9604)132 — boulders locally
44 8 2.5 Y /2 ¡J 136 --I4 5 YR6/4
48- 140- '2 Jointed locally 52- -16 a I Unit preserved only locally 56-" m
-18 Major unconformity
10 _ (highly irregular) --20 _48 Permian bedrock (siltstone): T Quartermaster Formation
JC5= 8 -22
*Color on fresh, dry surface
j Faulted, jointed, and
84- downwarped locally -26 Figure 7. Composite type section of the Lingos Formation. Units 1-7, lower Lingos Formation. Units 8-18, middle Lin- gos Formation. Units 19-22, upper Lingos Formation.
contemporaneous with sedimentation, and includes all three major lithofacies and is correl- of microvertebrates and absence of restricted many, if not all, of the Lingos deposits filling ative with representative sections elsewhere. megafauna at this and other sites limit the utility subsidence basins are faulted and downwarped. Fossils have been found at some exposures of of these vertebrate remains for paleoclimatic in- Lower Lingos deposits cap most of the major the lower Lingos. Molluscan remains are un- terpretation; however, many of the vertebrates modern drainage divides and other high points common and localized, and the diversity of taxa are important chronologic indicators. All of the on the paleosurface. Highs on the paleosurface, is low. Remains of vertebrates have been recov- large mammals represented in the lower Lingos particularly those farthest east in the Lingos ter- ered at a few localities including the Edwards appear to be part of the Rancholabrean faunal rane, underwent prolonged erosion and subsi- farm, type area of the Quitaque local fauna association. Deposits containing these fossils dence. There, the Lingos section, although thin, (Dalquest, 1964b) (Fig. 2, site N). The scarcity probably are much younger than 300 ka.
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EXPLANATION less than 40 ka. Paducah Group deposits in Childress County contain an Irvingtonian fauna INTERSTRATAL BOUNDARY FOSSIL and therefore range in age from 1.88 m.y. to 300 ka (Dalquest, 1964a; Lundelius and others, „„//,/// Gradual, smooth ff Gastropod 1987) (Fig. 3). These gravel deposits occupy a position higher in the landscape than do relict Sharp, smooth 0 Root cast Lingos strata to the west and clearly predate the Abrupt, irregular (degree and Lingos Formation. style of irregularity indicated) ì Root trace In the Lingos Formation type area and at a few other localities, a thin veneer of dark OTHER Burrow reddish-brown, clayey, sandy, and rarely grav- elly silt (Fig. 7, unit 1) underlies the coarse Radiocarbon sample (organic Y Track terrigenous clastics characteristic of the lower humates in sediments) Lingos. The silty sediment mantles and closely resembles underlying Permian bedrock from SEDIMENTARY TEXTURE which it was evidently derived by weathering in place, with minor contributions of slope wash, Clay Silt including lithoclasts of Ogallala calcrete. Lo- • # • • Sand • • • • Gravel cally, relict bedding within the silty veneer can be traced laterally into strata of the irregular Boulder (lithology Boulder (caliche, © Permian subcrop. Most of the silty basal Lingos not indicated) •• chert, siltstone) ÉP deposit appears to be a saprolite. Age of the Silty clay -1 Clayey silt saprolite is unknown, although it certainly post-
— — dates local retreat of the Caprock Escarpment. Sandy silt Silty sand In part, the saprolite may be time equivalent to Sandy clay Clayey sand coarse clastic deposits characteristic of the lower •. •• «• •. •• Lingos elsewhere. From the few exposures and Gravelly sand • • . . « • • •• .• .• Sandy gravel wells where the saprolite is known, however, it consistently underlies coarse clastic sediments. SEDIMENTARY STRUCTURE Erosion prior to or simultaneous with deposition F»: of sands and gravels of the lower Lingos proba- Tabular crossbeds Trough crossbeds bly eliminated the silty saprolitic veneer from Horizontal lamination Lens (intrastratal, basal) most areas. Even within a single outcrop, the saprolite invariably is discontinuous laterally. Rip-up clast Concretion Where present, it is part of the lower Lingos. Soft-sediment Graded beds (fining deformation £>. direction indicated) Middle Lingos Formation: Lacustrine Deposits PEDOGENIC STRUCTURE
Blocky Lenticular Iithosomes of clay-rich sediment 0 a composing the middle Lingos Formation overlie Prismatic the coarse clastics of the lower Lingos. In con- trast with the lower Lingos, strata composing the Columnar middle part of the formation generally are dis- Calcareous laminae continuous along strike. Middle Lingos sediment (relative continuity accumulated in lacustrine basins on then- indicated) inactive fan lobes (Fig. 10c). Lingos lacustrine deposits crop out at numerous sites as much as Figure 7. (Continued). 50 km east of the Caprock Escarpment and are recognized in water-well logs and cuttings. The Blair water well in southeastern Briscoe County Beds of clay conformably overlying the fossil- gos. Lingos chronology is further corroborated (Fig. 2) was drilled through a 2.7-m-thick layer bearing sands at the Quitaque fauna site have by regional projections of minimum rates of es- of organic-rich, highly fossiliferous (gastropods, been radiocarbon dated (Dalquest, 1964b; carpment retreat (Gustavson and others, 1981), bivalves, ostracodes) lacustrine clay at 35 m Caran and Baumgardner, 1986b). The age of as well as by the Rancholabrean fauna. In most depth (Caran and Baumgardner, 1984). Samples humates from these clay-rich strata exceeds 38 areas, the lower Lingos is between 300 and 40 of this clay were bright blue when fresh, indicat- ka. Radiocarbon ages of approximately 23 to 15 ka old. Lower Lingos deposits almost certainly ing reduction at depth. Drillers' logs from other ka were obtained higher in a correlative section are diachronous; their age probably increases to water wells in the region also report distinctive at the Smith farm site (Fig. 7, unit 14). These the east, where some strata may be nearly as old blue clay at various depths. All of these wells analyses help constrain the age of the lower Lin- as 300 ka, and decreases to the west, perhaps to penetrated locally thickened sections of Quater-
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EXPLANATION
Modern '-yyi Lacustrine Gravelly Sandy Silly sand K* Fractures (joints and Permian bedrock ex- and buried clay sand gravel small normal faults posed 500m south soils
Figure 8. Fractures in Permian and Quaternary strata exposed in the Lingos Formation type area, (a) Cross section through fractured and downwarped sand and gravel beds at the southern margin of the subsidence basin, (b) Dip of downwarped lacustrine strata varies from 5° to 16° vertically, (c) Faults, joints, and antithetic fractures. Scale bar is 30 cm long.
nary sediment marked by closed isopachous fossiliferous, calcareous clay and silt. In the Lin- lake. The fine sediment settled into tranquil contours. Lakes as much as 2.5 km in diameter gos Formation type area, lacustrine laminae water probably below wave base. Root traces occupied structural depressions defined on the were deposited horizontally, but subsequent throughout these deposits indicate that water Permian subcrop (Fig. 5). These basins formed downwarping produced small fractures and dips depths did not exceed the photic limit (presum- by subsidence resulting from dissolution of Per- of 10° to 16° toward the basin center (Fig. 8c). ably 5 m or less). mian halite. Some basins continued to subside The dip of these lacustrine strata increases Most of the water in this lake almost certainly while accumulating sediment. downward through the section, indicating re- was emergent ground water. The floor and Lacustrine deposits occupy a stratigraphically peated or continual downwarp during deposi- lower flanks of the subsidence basin likely consistent position in most Lingos sections, cor- tion. Much of the lacustrine sediment was dipped beneath the water table as underlying responding to a period in which differential sub- autochthonous (biogenic and authigenic). strata warped downward. The zone of saturation sidence was pronounced and humid climatic Coarse clastic detritus is virtually absent, and would have been relatively high because of conditions and discharge from the Ogallala most beds are texturally homogeneous from humid conditions and hydrologic continuity be- aquifer maintained a high regional water table. basin margin to basin center. These factors indi- tween the Ogallala aquifer and the Lingos For- Subsidence may have been more rapid and lat- cate that local runoff and sediment transport mation prior to extensive dissection of the erally extensive during this prolonged wet inter- were restricted. Allochthonous constituents were Lingos. These conditions produced water-table val than at any later time. The resulting carried by wind and by centripetal drainage lakes similar to those in the Bottomless Lakes subsidence basins filled with laminated, highly from a watershed only slightly larger than the sinkholes in Chaves County, New Mexico, and
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DEPOSITION A L AGE STRATIGRAPHIC ENVIRONMENT (years THICKNESS GENERAL STRATIGRAPHY COMPONENT AND PALEOECOLOGY before present)
Prairies, intermittent streams, ephemeral ponds, dune fields; modern vertebrate fauna; many mollusks extirpated. -1,000-
upper Lingos -5,000 -
-8,000 • Shallow perennial lakes; extinction or extirpation of Rancholabrean mammalian fauna; extensive molluscan -13,000- middle fauna including many species now Lingos extirpated regionally.
-35,000+-
Coalescing alluvial fans and broad, shallow, intermittent stream channels Rancholabrean vertebrate fauna (including Quitaque local fauna); few Late and Middle (?) lower molluscan remains preserved. Pleistocene Lingos
Saprolite and slope-wash deposits Late and/or -.1/ V-- / .. Middle Pleistocene local (unconformity) saprolite Permian \ (relict) or Triassic Permian or Triassic bedrock not to scale bedrock
Figure 9. Composite stratigraphie sequence for the Lingos Formation, based on regional distribution of major lithofacies.
to a few existing small lakes in the Rolling Plains chemistry. Lacustrine strata are highly calcare- ern fauna. These disjunct taxa are important (Caran and others, 1986). The steep-walled ce- ous, probably as a result of relatively high solute paleoclimatic indicators, providing evidence of a notes of the Bottomless Lakes may have been load (calcium and bicarbonate) of lake waters. marked change in the terrestrial environment. created by rapid or even catastrophic collapse, Clays of the middle Lingos in the type area are Skeletal remains of terrestrial and aquatic verte- such as that which produced the Wink Sink in more calcareous than are correlative strata at brates also have been recovered from lacustrine Winkler County, Texas, in 1980 (Baumgardner most other localities. strata at this site and some other areas. Few of and others, 1982). Although the processes that Most Pleistocene lakes of the Rolling Plains the represented species provide significant in- produced subsidence in the Rolling Plains dur- supported diverse aquatic molluscan faunas as formation regarding the paleoenvironment, ing the time of middle Lingos deposition are well as fish and other aquatic vertebrates, ostra- however; they merely reinforce the conclusion comparable to those active in the region today, codes, diatoms, and the benthic macrophytic that the lakes were perennial. The megafauna most of the Pleistocene lakes probably were alga Chara, which produced abundant calcare- appears to be Rancholabrean, although very lit- created by gradual subsidence of broad basins ous sediment. Paleontologic and stratigraphic tle Bison material has been found in place. with less steeply dipping margins. evidence indicates that the Pleistocene lake at Radiocarbon analyses are consistent with the The paleolake at the Lingos type area was the Edwards farm site (Caran and Baumgardner, available biochronologic evidence. Radiocarbon almost certainly perennial, but water level prob- 1986b; Dalquest, 1986) was larger and deeper ages of lacustrine deposits range from 25 to ably fluctuated. The local paleofauna includes and supported more diverse faunas than that at about 6.5 ka, although most exceed 8 ka molluscan species that typically occupy habitats the Smith farm. Shells of terrestrial mollusks, (Baumgardner and Caran, 1986b). A nearly with seasonal inundation, like those at the mar- which occupied woodland habitats adjacent to continuous series of latest Pleistocene to earliest gins of a lake (Caran and others, 1985) (Table the paleolake, are common in lacustrine strata at Holocene dates was obtained in the Lingos type 2). Limited diversity of the molluscan fauna at the Edwards farm. All molluscan taxa are ex- area. Conditions favoring the existence of per- this site also may reflect unfavorable water tant, but most are absent from the region's mod- ennial lakes appear to have deteriorated region-
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Figure 10. Block-diagram representation of Lingos deposi- tional history, (a) Alluvial fans, (b) Bajada. (c) Ground- water-sustained lakes in subsidence basins, (d) Fluvial incision and initial integration of modern drainage net- work. (e) Modern entrenched drainage network, eolian deposits, and spring sapping.
ally after about 8,000 yr ago (Caran and others, its containing paleosols at many sites (Fig. 9). sediments from the Ogallala aquifer, and asso- 1985). These deposits contrast sharply with the under- ciated geomorphic adjustments. lying lacustrine sediments from which they Rapid transition from typical middle Lingos Upper Lingos Formation: Fluvial generally are separated by erosional unconform- depositional environments to those of the upper and/or Eolian Deposits ities. Such a marked, regionally extensive Lingos appears to coincide with progressive re- replacement of one major environment of depo- gional desiccation that began in early Holocene The uppermost lithofacies of the Lingos For- sition with another probably resulted from cli- time (Caran and others, 1985; Neck, 1987). mation is a series of fluvial and/or eolian depos- matic change, hydrologie isolation of the Lingos Drier conditions would have reduced recharge,
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TABLE 2. SPECIES ABUNDANCE FOR MOLLUSCAN but extensive, fine-grained, eolian deposits. Most nal sequence there indicates gradual warming PALEOFAUNA AT LINGOS FORMATION COMPOSITE TYPE SECTION of the eolian material probably was winnowed and desiccation culminating in the warm, dry from local stream beds and flood plains during conditions of today (Caran and others, 1985; Species name Stratigraphie unit dry seasons and was redeposited on adjacent Neck, 1987). 13 14 15 16 17 vegetated surfaces. This process still occurs throughout the region. Fluvial and eolian depos- PADUCAH GROUP (NEW) Carychium mexicanum r r Valtonia parvula r its interfinger in some localities, but at most sites, Pupilla muscorum r Pupoides aibilabris r r the upper Lingos is dominated by one or the The newly designated Paducah Group in- Gasirocopta cristate r other. cludes the Lingos Formation, the previously Gastrocopta tappaniana c Vertigo milium c r Stable and slowly aggrading surfaces devel- described Seymour, Good Creek, and Groes- Vertigo ovata r Succinea sp. r oped relatively thick soils. Stacked paleosols at beck Formations, and several unnamed strati- Euconulus trochulus r the Lake Theo archeological site (Fig. 2, site B) graphic units (Fig. 3). Formations composing Fossaria obrussa r a r Fossaria dalli c are part of the upper Lingos Formation. These this group are genetically similar and lie within Stagnicoia exiiis r a Aptexa hypnorum r paleosols contain diagnostic, early to late Holo- close proximity to one another in the vicinity of Amiger crista a cene cultural materials and yield stratigraphi- Paducah, Cottle County, Texas (Fig. 1). The Gyraulus circumsniatus c a a Gyraulus parvus c r a a cally consistent radiocarbon ages (Johnson and oldest of these formations, the Seymour, lies Promenetus exacuous r a Promenetus umbilicaiellus a others, 1982; Caran and Baumgardner, 1986a). farthest east, as much as 160 km from the Cap- Johnson and others (1982) stated that soils at rock Escarpment. Menzer and Slaughter (1971) Note: r = I to 5, c = 6 to 10, a > 10 individuals. For description of this locality are moderately well developed speculated that the Seymour Formation was stratigraphie units, see Figure 7. Data from Caran and others (1985). Species identified by R. W. Neck (Texas Parks and Wildlife Department) and R W. (thick clayey B horizons, 5YR and 7.5YR col- deposited proximal to a retreating protoescarp- Fullington (Dallas Museum of Natural History). ors, and strong to moderate structure), but these ment marking the eroded edge of the Ogallala properties were imparted at the time of deposi- Formation. The lower Lingos Formation was tion or acquired soon after. Little pedogenesis deposited in the same manner. Hibbard and was required to produce these soil characteris- Dalquest (1966) described probable lacustrine deposits, similar to the middle Lingos, within the lowered the shallow water table, and virtually tics, because of local availability of abundant Seymour. The Seymour Formation is capped eliminated perennial lakes from the region de- calcium carbonate (derived from Ogallala litho- with an eolian veneer (Ogilbee and Osborne, spite continued subsidence. The rate of dissolu- clasts) and red, iron-rich, silty-clay parent 1962), as is most of the upper Lingos. These tion subsidence may have decreased, as well, materials (eroded from Permian and Triassic red similarities justify placement of the Seymour although individual subsidence basins continued beds) (Caran, 1987). Generative sediments at and Lingos in a single lithostratigraphic unit, the to enlarge. Lateral expansion of individual the Lake Theo site accumulated during only a Paducah Group. Seymour deposits include an basins in and near the Lingos type area also may few thousand years but exhibit morphological Irvingtonian land-mammal fauna and the 620- have enhanced downcutting. Caran and Baum- characteristics such as reddish hues, clayey tex- ka Lava Creek B volcanic ash, both of which gardner (1988,1990) concluded that most of the ture, and prismatic structure typical of much predate the Lingos Formation as currently downcutting in the western Rolling Plains dates older, strongly developed soils elsewhere (see recognized. from middle to late Holocene. Dry conditions Harden and Taylor, 1983). accentuated flashy, highly erosive streamflow as The chronology of the upper Lingos is well Other formations composing the Paducah vegetative cover diminished, resulting in the constrained by radiocarbon age determinations Group are less fully described but are similar to downcutting that is characteristic of much of the (Caran and Baumgardner, 1986a), closely cor- the Seymour and Lingos. All lie between, but region today (Finley and Gustavson, 1980). In- responding to archeological, faunal, and geo- are geographically separated from, the Lingos cision probably helped to deplete shallow aqui- morphic indications of age. None of the and Seymour terranes. High gravels in Childress fers, further lowering the water table. These radiocarbon ages for the upper Lingos is older County contain apparent Irvingtonian faunas processes would have interacted in complex than early to middle Holocene; however, deposi- and may be coeval in part with the Seymour ways over an extended period. The rate of tion of the upper Lingos was locally discontinu- Formation (Dalquest, 1964b) (Figs. 1 and 3). westward retreat of the Caprock Escarpment, ous, and some strata may have accumulated Some of the Quaternary deposits in Childress and the corresponding accumulation of Paducah- during latest Pleistocene time. Incision that pro- County and adjacent parts of Hall County oc- type deposits, depended, in part, on the relative duced modern stream channels and most valleys cupy subsidence basins and are 60 m to more magnitude and duration of episodes of subsi- of the western Rolling Plains postdates most of than 135 m thick (George and Foster, 1942; dence and erosion. the Lingos strata (Figs. 1 and 2), indicating Hol- Popkin, 1973). These deposits include lacustrine Under the relatively dry conditions of early to ocene integration of much of the existing drain- clays as well as coarse clastic sediment and brec- middle Holocene time, small meandering and age network (Fig. lOe). cia. In Stonewall County, gravel containing a braided streams truncated lacustrine deposits In general, the upper Lingos appears to be the possible Sangamon fauna, including a large and buried them beneath thin-bedded sands and lithostratigraphic record of the Holocene Epoch. bison, is inset below an older, more extensive gravels (Fig. lOd). Sandy deposits of the upper Little fossil material has been recovered from gravel that lacks vertebrate remains but which Lingos Formation contain small-scale sedimen- these deposits. Mammalian skeletal debris has may be a Seymour equivalent (E. L. Lundelius, tary structures and individual channel forms. Di- been found at a few sites and, although generally 1986, personal commun.). The Good Creek rections of paleotransport were predominantly poorly preserved and in some cases reworked Formation, Foard County (Dalquest, 1962), eastward but highly variable. Streams were in- from older strata, does represent the Holocene and the Groesbeck Formation, Hardeman termittent with flashy discharge, transporting (post-Rancholabrean) fauna (Johnson and oth- County (Dalquest, 1965), consist of lacustrine mixed bedloads across a surface of low gradient ers, 1982; Caran and Baumgardner, 1984). Mol- sediments and minor fluvial deposits filling sub- through shallow, laterally unstable channels. luscan faunas are represented only locally. The sidence basins. Radiocarbon ages of 19 to 16 ka Much of the upper Lingos consists of aggrading, most complete and thoroughly dated record of for the Groesbeck Formation are based on anal- cut-and-fill sequences. latest Pleistocene and Holocene mollusks is that yses of molluscan shells (Dalquest, 1965). In addition, the upper Lingos includes thin from the Lake Theo archeological site. The fau- Although nonmarine shells are not ideal mate-
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rials for radiocarbon dating, ages reported by table that was intercepted as the basins subsided. tavson, T. F. Hentz, V. T. Holliday, R. F. Ma- Dalquest overlap radiocarbon ages from the Subsidence continues throughout the region, dole, and Amos Salvador improved the manu- middle Lingos Formation (Caran and Baum- producing sinkholes and broad collapse basins, script. This study was funded by the U.S. gardner, 1986a). Dalquest (1986) concluded but because the water table has remained rela- Department of Energy under Contract DE- that the vertebrate fauna of the Groesbeck For- tively low throughout the Holocene, there were AC97-83WM46651. mation is comparable in age or slightly younger few lakes during this period. In contrast, lakes than the Quitaque local fauna, which was re- were common during the Pleistocene and pro- covered from the lower Lingos and the base of vided habitats for abundant aquatic mollusks, the middle Lingos. Therefore, the Groesbeck including several species no longer extant re- REFERENCES CITED Formation and middle Lingos Formation may gionally. In middle Lingos deposits, fossil ostra- Baumgardner, R. W., Jr., and Caran, S. C., 1986a, Stop 11, measured section. Fort Worth and Denver Railroad cut, in Gustavson, T. C., ed., Geo- be coeval, in part. The Good Creek Formation codes, diatoms, a few microvertebrates, and the morphology and Quaternary stratigraphy of the Rolling Plains, Texas contains a fauna that appears to predate the Qui- benthic macrophytic alga Chara also are com- Panhandle: University of Texas at Austin, Bureau of Economic Geology Guidebook 22, p. 47-55. taque local fauna (Dalquest, 1986) and middle mon, as are allochthonous remains of terrestrial 1986b, Stop 15, measured section, Henson farm near Quitaque, Texas, in Gustavson, T. C., ed., Geomorphology and Quaternary stratigraphy Lingos Formation but may be coeval with the mollusks and some large vertebrates. of the Rolling Plains, Texas Panhandle: University of Texas at Austin, lower Lingos. These and other unnamed forma- Bureau of Economic Geology Guidebook 22, p. 67-72. At most sites, the top of the middle Lingos Baumgardner, R. W., Jr., Hoadley, A. D., and Goldstein, A. G., 1982, Forma- tions shown in Figure 3 bear a close genetic deposits is an erosional unconformity. Follow- tion of the Wink Sink, a salt dissolution and collapse feature, Winkler County, Texas: University of Texas at Austin, Bureau of Economic relationship and may be considered a single ing the relatively wet interval during which the Geology Report of Investigations 114, 38 p. group. Brown, L. F., Jr., Goodson, J. L., and Harwood, P., 1972, Geologic atlas of middle Lingos was deposited, the regional cli- Texas—Abilene sheet: University of Texas at Austin, Bureau of Eco- mate became increasingly arid. Eolian and in- nomic Geology, scale 1:250,000. Budnik, R. T., 1987, Late Miocene reactivation of Ancestral Rocky Mountain CONCLUSIONS termittent fluvial sedimentation contributed structures in the Texas Panhandle: A response to Basin and Range extension: Geology, v. 15, no. 2, p. 163-166. most of the upper part of the Lingos section. Caran, S. C., 1987, Rapid Quaternary pedogenesis, Rolling Plains of Texas These upper deposits were modified pedogeni- [abs.]: Association of American Geographers Newsletters, v. 22, no. 7, Representative sections of the Quaternary p. 14. Lingos Formation compose three distinct litho- cally to a greater extent than were most other 1990, Upper Cenozoic stratigraphy, southern Great Plains and adjacent areas, in Morrison, R. B., ed.. Quaternary nonglacial geology, coter- facies (Fig. 9). Gravelly sediments of the lower parts of the Lingos section, possibly as a result of minous United States: Geological Society of America, Decade of North Lingos probably were deposited by alluvial fans the relatively low water table during the Holo- American Geology, v. K-2 (in press). Caran, S. C., and Baumgardner, R. W., Jr., 1984, Quaternary stratigraphy and spreading eastward from the retreating Caprock cene and consequent thick vadose zone. geologic mapping, western Rolling Plains of Texas: University of Texas at Austin, Bureau of Economic Geology Open-File Report OF-WTWI- Escarpment. At a few sites, this coarse clastic The depositional history of the Lingos Forma- 1984-49, 17 p. component contains Rancholabrean faunal re- 1986a, Appendix—Summary of radiocarbon dates, western Rolling tion parallels the genesis of all Quaternary strati- Plains of Texas, in Gustavson, T. C., ed., Geomorphology and Quater- mains, indicating that the age of these deposits is graphic units of the Rolling Plains that compose nary stratigraphy of the western Rolling Plains, Texas Panhandle: Uni- versity of Texas at Austin, Bureau of Economic Geology Guidebook 22, less than 300 ka. Regional subsidence trapped the newly designated Paducah Group. Since the p. 90-97. this sediment along the retreating edge of the 1986b, Stop 12A, Quitaque Creek section, in Gustavson, T. C., ed., middle Pleistocene, the Rolling Plains has un- Geomorphology and Quaternary stratigraphy of the Rolling Plains, ancestral Caprock Escarpment. dergone repeated cycles of regional subsidence, Texas Panhandle: University of Texas at Austin, Bureau of Economic Geology Guidebook 22, p. 56-57. Overlying the lower Lingos gravels are lenses retreat of the Caprock Escarpment, construction 1986c, Stop 14, measured section, Smith farm, Quitaque, Texas, in Gustavson, T. C., ed., Geomorphology and Quaternary stratigraphy of of fossiliferous lacustrine silt and clay of the of alluvial fans, creation of ground-water- the Rolling Rains, Texas Panhandle: University of Texas at Austin, middle Lingos. These lenses are important strat- sustained lakes through local differential subsi- Bureau of Economic Geology Guidebook 22, p. 63-66. 1988, The Lingos Formation, western Rolling Plains of Texas, in Hay- igraphie markers within many Lingos sections. dence, gradual integration of through-going ward, O. T., ed., Decade of North American Geology, Geological So- ciety of America Centennial Field Guide-South-Central Section The fine-grained sediment accumulated in closed drainage, and pronounced downcutting and (Volume 4): Boulder, Colorado, Geological Society of America, basins containing ponds and small lakes. Ac- denudation. Dynamic landscape evolution con- p. 287-292. 1990, Quaternary geology of the Rolling Plains, in Morrison, R. B., ed.. cumulation of lacustrine deposits was enhanced tinues to characterize this region today. Quaternary nonglacial geology, coterminous United States: Geological Society of America, Decade of North American Geology, v. K-2 (in by karstic subsidence. Closed structural depres- press). Caran, S. C., Neck, R. W., and Fullington, R. W., 1985, Paleoclimatic recon- sions on the eroded pre-Quaternary surface are ACKNOWLEDGMENTS struction based on molluscan (Gastropoda, Pelecypoda) environmental filled with faulted, downwarped, lacustrine and indicators—Late Quaternary of northwestern Texas: University of Texas at Austin, Bureau of Economic Geology Open-File Report fluvial Quaternary deposits. Beds and individual We express our appreciation to the many OF-WTWI-1985-27, 35 p. Caran, S. C., McGookey, D. A., and Neck, R. W., 1986, Ground-water lakes- laminae thicken across some faults, whereas landowners in the Rolling Plains study area Modern and Pleistocene examples from New Mexico and Texas: Geo- other strata are merely offset, indicating that who graciously granted access to their property. logical Society of America Abstracts with Programs, v. 18, no. 3, p. 214. Cummins, W. F., 1893, Notes on the geology of northwest Texas: Austin, subsidence occurred episodically. R. W. Neck and R. W. Fullington shared their Texas Geological Survey, 4th Annual Report, pt. 1, p. 177-238. Dalquest, W. W., 1962, The Good Creek Formation, Pleistocene of Texas, and Before subsidence basins were isolated from expertise on the molluscan paleofauna. V. T. its fauna: Journal of Paleontology, v. 36, no. 3. p. 568-582. external sediment sources, they trapped fluvial Holliday provided assistance with analysis of 1964a, A new Pleistocene local fauna from Motley County, Texas: Kansas Academy of Sciences Transactions, v. 67, p. 499-505. sand and gravel transported eastward from the buried soils. Participants in the 1984 field trip of 1964b, Equus scoili from a high terrace near Childress, Texas: Texas Journal of Science, v. 16, no. 3, p. 350-358. escarpment. These deposits of coarse sediment the South-Central Cell of Friends of the Pleisto- 1965, New Pleistocene formation and local fauna from Hardeman cene and 1986 field trip of the Geological So- County, Texas: Journal of Paleontology, v. 39, no. 1, p. 63-79. are important fresh-water aquifers. Leakage of 1986, Stop 12B, vertebrate fossils from a strath terrace of Quitaque unsaturated ground water from these aquifers ciety of America shared their views on key Creek, Motley County, in Gustavson, T. C-, ed., Geomorphology and Quaternary stratigraphy of the Rolling Plains, Texas Panhandle: Uni- may have accelerated dissolution of subjacent outcrops. All errors of interpretation are the au- versity of Texas at Austin, Bureau of Economic Geology Guidebook 22, thors' own. Research assistants included Matt p. 58-59. Permian evaporites, thereby promulgating sub- Eifler, G. K., Jr., 1967, Geologic atlas of Texas—Lubbock sheet: University of sidence. The resulting subsidence basins were Myers, Paula Noble, Diane Robinson-Poteet, Texas at Austin, Bureau of Economic Geology, scale 1:250,000. 1968, Geologic atlas of Texas—Plainview sheet: University of Texas at ground-water lakes, sustained by a high water and Elizabeth Thorakos. Reviews by T. C. Gus- Austin, Bureau of Economic Geology, scale 1:250,000.
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D., ed., Fluvial sedimentology: Rolling Plains and along the Caprock Escarpment of the Texas Pan- ogy and Quaternary stratigraphy of the Rollings Plains, Texas Pan- Calgary, Canada, Canadian Society of Petroleum Geologists Memoir 5, handle: University of Texas at Austin, Bureau of Economic Geology handle: University of Texas at Austin, Bureau of Economic Geology p. 597-604. Geological Circular 80-11,49 p. Guidebook 22, p. 45-46. Naeser, C. W., Izett, G. A., and Wilcox, R. E„ 1973, Zircon fission-track ages Frye, J. C., and Leonard, A. B., 1957, Studies of Cenozoic geology along Havens, J. S., 1977, Reconnaissance of the water resources of the Lawton of Pearlette family ash beds in Meade County, Kansas: Geology, v. 1, eastern margin of Texas High Plains, Armstrong to Howard Counties: quadrangle, southwestern Oklahoma: Norman, Oklahoma, University no. 4, p. 187-189. University of Texas at Austin, Bureau of Economic Geology Report of of Oklahoma, Oklahoma Geological Survey Map HA-6, scale Neck, R. W., 1987, Changing Holocene snail faunas and environments along Investigations 32,62 ,). 1:250,000. the eastern Caprock Escarpment of Texas: Quaternary Research, v. 27, 1963, Pleistocene geology of Red River Basin in Texas: University of Hentz, T. F., and Brown, L. F„ Jr., 1987, Geologic atlas of Texas—Wichita no. 3, p. 312-322. Texas at Austin, Bureau of Economic Geology Report of Investi- Falls-La wton sheet: University of Texas at Austin, Bureau of Economic Ogilbee, William, and Osborne, F. L., Jr., 1962, Ground-water resources of gations 49.48 p. Geology, scale 1:250,000. Haskell and Knox Counties, Texas: Austin, Texas Water Commission Frye. J. C., Swineford. A., and Leonard, A. B., 1948, Correlation of Pleistocene Hibbard, C. W., and Dalquest, W. W., 1966, Fossils from the Seymour Forma- Bulletin 6209, 185 p. deposits of the central Great Plains with the glacial section: Journal of tion of Knox and Baylor Counties, Texas, and their bearing on the late Osterkamp, W. R., 1987, Groundwater—An agent of geomorphic change, in Geology, v. 56, no. 6, p. 501-525. Kansan climate of that region: Ann Arbor, Michigan, University of Graf, W. L., ed., Geomorphic systems of North America: Geological Galloway, W. E., 1981, Depositional architecture of Cenozoic Gulf Coastal Michigan, Contributions from the Museum of Paleontology, v. l,no. 1, Society of America, Decade of North American Geology, v. 2, Plain fluvial systems, in Ethridge, F. G„ and Flores, R. M., eds.. Recent p. 1-66. p. 188-195. and ancient nonmarine depositional environments—Models for explo- 1973, Proneofiber, a new genus of vole (Cricetidae: Rodentia) from the Palmer, A. R., 1983, Decade of North American Geology 1983 geologic time ration: Society of Economic Paleontologists and Mineralogists Special Pleistocene Seymour Formation of Texas, and its evolutionary and scale: Geology, v. 11, no. 9, p. 503-504. Publication 31, p. 127-155. stratigraphic significance: Quaternary Research, v. 3, no. 2, p. 269-274. Popkin, B. P., 1973, Ground-water resources of Hall and eastern Briscoe Coun- George, W. O., and Foster, C. V.. 1942, Childress County, Texas—Records of Izett, G. A., 1981, Volcanic ash beds—Recorders of upper Cenozoic silicic ties, Texas: Texas Water Development Board Report 167, 84 p. wells, drillers' logs, water analyses, and map showing locations of wells: pyroclastic volcanism in the western United States: Journal of Geophys- Simpkins, W. W., and Baumgardner, R. W., Jr., 1982, Stream incision and Austin, Texas, Texas State Board of Water Engineers, 39 p. ical Research, v. 86, no. 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Geology distributions of the Huckleberry Ridge, Mesa Falls, and Lava Creek ash Palo Duro Basin, Texas Panhandle—A report on the progress of and geohydrology of the Palo Duro Basin, Texas Panhandle—A report beds (Pearlette family ash beds) of Pliocene and Pleistocene age in the nuclear waste isolation feasibility studies (1981): University of Texas at on the progress of nuclear waste isolation feasibility studies (1982): western United States and southern Canada: Washington, D.C., U.S. Austin, Bureau of Economic Geology Geological Circular 82-7, University of Texas at Austin, Bureau of Economic Geology Geological Department of the Interior, U.S. Geological Survey Miscellaneous In- p. 160-163. Circular 834, p. 128-132. vestigations Series Map 1-1325, scale 1:4,000,000. Smith, J. T., 1973, Ground-water resources of Motley and northeastern Floyd Gustavson, T. C„ and Holliday, V. T., 1985, Depositional architecture of the Johnson, Eileen, Holliday, V. T„ and Neck, R. 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I, p. 47-60. the Caprock Escarpment and denudation of the Rolling Plains in the Lundelius, E. L., Jr., Churcher, C. S., Downs, Theodore, Harington, C. R., West Texas Geological Society, 1976, Lexicon of Permian stratigraphic names Texas Panhandle: Association of Engineering Geologists Bulletin, v. 18, Lindsay, E. H., Schultz, G. E, Semken, H. A., Webb, S. D„ and of the Permian Basin of West Texas and southeastern New Mexico: no. 4, p. 413-422. Zakrzewski, R. J., 1987, The North American Quaternary sequence, in Midland, Texas, West Texas Geological Society Publication 76-66, Gustavson. T. C., Simpkins, W. W., Alhades, Alan, and Hoadley. Ann. 1982. Woodburne, M. O., ed., Cenozoic mammals of North America— 341 p. Evaporite dissolution and development of karst features on the Rolling Geochronology and biostratigraphy: Berkeley. California, University of Plains of the Texas Panhandle: Journal of Earth Surface Processes and California Press, p. 211-235. Landforms, v. 7, no. 6, p. 545-563. 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