Regional Strucutal Cross Sections, Mid-Permian to Quaternary Strata
Total Page:16
File Type:pdf, Size:1020Kb
REGIONAL STRUCTURAL CR .-~--- SECTIONS, MID-PERMIAN TO QUATERN RY STRATA, TEXAS PANHANDLE AND EASTERN NEW MEXICO DISTRIBUTION OF EVAPORITES AND AREAS OF EVAPORITE DISSOLUTION AND COLLAPSE Douglas A. McGookey, Thomas C. GUltavson, and Ann D. Hoadley BUREAU OF ECONOMI GEOLOGY W. L. Fisher, Director 1985 of at Austin Austin, Texas 78713 REGIONAL STRUCTURAL CR SECTIONS, MID-PERMIAN TO QUATERN RYSTRATA, TEXAS PANHANDLE AND EASTERN NEW MEXICO DISTRIBUTION OF EVAPORITES AND AREAS OF EVAPORITE DISSOLU·TION AND COLLAPSE Douglas A. McGookey, Thomas C. Gustavson, and Ann D. Hoadley BUREAU OF ECONOMI GEOLOGY W. L. Fisher, Director xas at Austin Funded by the U.S. Department of Energy Contract Number DE-AC97-83WM466S1 OF-WTWI-1985-48 REGIONAL STRUCTURAL CROS SECTIONS, MID-PERMIAN TO QUATERNARY TRATA, TEXAS PANHANDLE AND EASTERN N WMEXICO Distribution of Evaporites and Areas of Evaporite Dissolution an Collapse by Douglas A. McGoo ey Thomas C. Gustav on and Ann D. Hoadley Prepared for the U. S. Department of E ergy Salt Repository Project Office under contract no. DE-AC97 83WM46651 Bureau of Economic Geol 9Y W. L. Fisher, Directo The University of Texas at ustin University Station, P. O. ox X Austin, Texas 78713 Contents Introduction ....................................................... Geologic setting of the Texas Panhandle ............................ 1 Salt dissolution and collapse of overlying strata ..................... 9 General explanation of cross sections ............................... ............................ 12 Summary .......................................................... 12 Acknowledgments ..............- ................................... 13 Selected bibliography .......................... '.................... 13 Appendix: List of gamma-ray logs used on cross sections ............ 19 Figures 1. Index map of the study area showing locations of cross sections... ............................ 2 2. Structural elements of the Texas Panhandle and adjacent areas .... ............................ 4 3. Evaporite, carbonate, and terrigenous clastic facies and inferred env ronments of middle and upper Permian rocks, Texas Panhandle. 5 4. Inferred paleogeography during the initial stage of Dockum sedime tation south of the Amarillo Uplift and Sierra Grande Arch. 6 5. Geologic time scale showing intervals of time represented by Permi n to Quaternary strata in the Palo Duro Basin ........................................................................ 7 6. Schematic illustration of Ogallala depositional facies and inferred se iment dispersal systems, Texas Panhandle. 8 7. Geographic extent of existing salt beds within the Texas Panhandle and eastern New Mexico.. 9 8. Cross section AA-AA' showing evidence for interpretation of salt di solution, Texas Panhandle. .. 11 Table Stratigraphic chart, Permian to Quaternary strata, Palo Duro Basin and surrounding area. 3 Cross Sections Regional structural cross sections A-A' through L-L', Texas Panhandle ..... " .. " ........... , in pocket COPYRIGHT STATEMENT Prepared for the U.S. Department of Energy under Contract Number DE-AC97-83WM466 1. By acceptance of this article, the publisher and/or recipient acknowledges the U.S. Govern ent's right to retain a nonexclusive, royalty free license in and to any copyright covering the article. Regional Structural Cross Sections, Mid-Per Ian to Quaternary Strata, Texas Panhandle and Eastern ew Mexico: Distribution of Evapo tes and Areas of Evaporite Dissolutio and Collapse Introduction The Palo Duro and Dalhart Basins of the Texas the Cana ian River valley (Gustavson and others, Panhandle and eastern New Mexico contain bedded 1980b; Pr sley, 1980a, 1980b). Permian salts of sufficient thickness and depth to be Region I cross sections of mid-Permian to considered potential sites for long-term storage and Quaterna strata in the Texas Panhandle and isolation of high-level nuclear waste. Salt (primarily eastern ew _ Mexico illustrate lithologic and halite) is a desirable host rock because of its low structural relations that are interpreted to have permeability, high thermal conductivity, low resulted fr m the regional dissolution of salt and the moisture content, and high gamma-ray shielding collapse 0 overlying strata. The cross sections were properties (Johnson, 1976b). construct d using gamma-ray logs, sample logs, A major concern that must be addressed if and surf ce geologic maps (Handford, 1980a; nuclear,waste is to be stored in the Texas Panhandle McGjllis, 980). Gamma-ray logs are shown on the is the long-term integrity of the bedded-salt host cross se tions because they best demonstrate rock. Areas where salt has been removed by variations in evaporite strata. Figure 1 is an index dissolution have been identified beneath the map depi ting the locations of the cross sections. Southern High Plains, along the eastern and western Stratigrap ic nomenclature used on the cross escarpments of the Southern High Plains, and along sections i given in table 1. Geologic Setting of the Texa During the early Paleozoic, episodes of shallow dominate early Pennsylvanian sedimentation and marine shelf deposition in the Texas Panhandle were derved from and concentrated near the alternated with periods of subaerial erosion. principal uplifts (Handford and Dutton, 1980). Cambrian(?) rocks· consist of arkosic and glau Sediment tion during the late Pennsylvanian was conitic sandstones (Birsa, 1977). Shallow-shelf characteri ed by shelf carbonate deposition; deeper carbonates of the Ellenburger Group were parts of th basin were filled by fine-grained clastics. deposited in the Early Ordovician (Dutton, 1979). Lower olfcampian (earliest Permian) shallow Upper Ordovician, Silurian, and Devonian strata are marine c rbonates, coarse arkosic depo.sits, and missing in the Texas Panhandle. During Missis deep-basi shales are overlain by upper Wolf sippian time, marine Shelf carbonate deposition campian olomitic rocks that were deposited in probably extended over the entire area. high-ener y oolite and skeletal grainstone environ In the late Paleozoic, blocks of crust were ments (Ha dford, 1980b; Hovorka and Budnik, 1983). uplifted to form the Wichita - Amarillo Uplift and the By Wichi a time, increasing restriction behind Matador Arch (Goldstein, 1982). These are the major supratidal or subtidal shoals created environ positive structural features bounding the Palo Duro ments in which carboJ1ates, terrigenous clastic Basin on the north and south, respectively, and they mudston ,and bedded gypsum (later converted to separate the Palo Duro Basin from the Anadarko, anhydrite were deposited (Handford, 1979, 1980b; , Dalhart, and Midland Basins (fig. 2). Terrigenous Hovorka nd Budnik, 1983). Limited faunal diversity, clastic sediments, informally called "granite wash," sparse bu rows, and the presence of anhydrite beds 1 indicate hypersaline conditions. During Red Cave Middle and upper Permian evaporite and clastic time, terrigenous clastic deposition alternated with sediments ere deposited in tabular beds landward carbonate-grainstone and bedded-anhydrite of oolitic b rs or shoals on a vast (62 by 124 mi deposition in hypersaline evaporite pans or [100 by 200 mJ) subtidal to subaerial flat. Red beds, lagoonward of supratidal environments (Hovorka which are ommonly intercalated with evaporites, and Budnik, 1983). consist of t rrestrially derived, fine-grained clastics Clear Fork, San Andres, and post-San Andres that were di tributed across the region by eolian and (middle and upper Permian) rocks are dominantly submarine processes (Bein and Land, 1982). dolomite, mudstone, salt, and anhydrite deposited Presley's ( 981) model of evaporite deposition in arid shallow-marine to subaerial environments. (fig. 3) was nferred from study of well logs, cores, '---T-- o ~ : OKLAHOMA i:5/ DALLAM --:';-;';,;==::;;:T ~A ~, 20 ~I~ X ~ ~y I ,~ GuADALUPE ~ o I 12 16 13 II F_'1 _~ ~ I~,"',.-k..- --t""/~'''''LuC::e·Boc SCALE L--. I I I °1-1--ro. _2...,0-..... _-,....4....,0_-r---'~Omi L_--1 I I 0 o 20 40 60 BOkm •• L_~_ I LU~_B-+-K-",, __ OAIOI, Fj'r-:;'" EXPLANATION 23 West East Division between the east and west halves of cross sections ~ Cross "ctions wllh verllcol exoQQerolion of 106X 3.', 13 8 ~ ,,_'3 I Cross sections wilh verlicol eKoQQeration of 53X Figure 1. Index map of the study area showing locat ona of cross sectlons. 2 and out crops. The model shows massive (banded) which orine composition changed as CaC03 , salt an d laminated and nodular anhydrite CaS04 , and NaCI were successively pre cipitated. sedimen tation by evaporation (1) in periodically Carbo n ~te strata in the upper San An dres and flooded brine pans, (2) on salt flats that were Alibate~ Formations consist predomin antly of isolated from open-marine water, and (3) on mud dolomi t ~. flats wh ere salt crystals grew by displacing the mud Sal t ~eds in the Palo Duro Basin range fr omafew matrix. Bein and Land's (1982) petrographic and feet to 200 ft (61 m) thick. Before disso lution of geochem ical study of the San Andres Formation in upper salt units in the northern Texas Pan handle cores, 0 n the other hand, indicates that evaporite and arc und the northern, eastern, and western rocks w ere deposited in a shelf basin or lagoon in margim of the Palo Duro Basin, the m ost wide- Table 1. Stratigraphic chart, Permian to Quaternary Itrata, Palo Duro Balin and surrounding area. Eastern System Series New Mexica Pala Dura Basin Dalhart Basin Anadarko Basin uuaternarv ~lackwat ... Qraw I'm. ~Iackwat.r Oraw I"m. t;llCIckwot.r