Environmental Reconstruction of a Carbonate Beach Complex: Cow Creek (Lower Cretaceous) Formation of Central Texas

Abstract

Research Article| April 01, 1973 Environmental Reconstruction of a Carbonate Beach Complex: Cow Creek (Lower Cretaceous) Formation of Central Texas F. L. STRICKLIN, JR.; F. L. STRICKLIN, JR. 1Shell Oil Company, P.O. Box 60775, New Orleans, Louisiana 70160 Search for other works by this author on: GSW Google Scholar C. I. SMITH C. I. SMITH 2Department of Geology and Mineralogy, University of Michigan, Ann Arbor, Michigan 48103 Search for other works by this author on: GSW Google Scholar Author and Article Information F. L. STRICKLIN, JR. 1Shell Oil Company, P.O. Box 60775, New Orleans, Louisiana 70160 C. I. SMITH 2Department of Geology and Mineralogy, University of Michigan, Ann Arbor, Michigan 48103 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1973) 84 (4): 1349–1368. https://doi.org/10.1130/0016-7606(1973)84<1349:EROACB>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation F. L. STRICKLIN, C. I. SMITH; Environmental Reconstruction of a Carbonate Beach Complex: Cow Creek (Lower Cretaceous) Formation of Central Texas. GSA Bulletin 1973;; 84 (4): 1349–1368. doi: https://doi.org/10.1130/0016-7606(1973)84<1349:EROACB>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The morphology of a typical beach is clearly shown by bedding in the Cow Creek Formation, which crops out as a downdip-thickening, 0- to 15-m limestone wedge on the southeastern flank of the Llano Uplift. The inferred beach deposits comprise the upper part of the formation over an area of at least 600 sq km (≃240 sq mi) and represent a minimum shoreline progradation of 40 km.The formation is comprised of three superposed, laterally equivalent facies described and interpreted as follows: A basal unit of fine-to-coarse, silty calcarenite and an overlying unit of fine-grained silty calcarenite are attributed to deposition in progressively shoaling waters; the coarsest grained coquina facies at the top of the formation is representative of beach deposition. The latter facies contains three diagnostic types of cross-bedding: (1) a lower section displaying festoon cross-beds, (2) an intermediate sequence of offlapping, planar cross-beds with consistent southerly dips, and (3) upper, locally developed northerly dipping beds. These three types of cross-beds are related, respectively, to the beach-toe, foreshore, and backshore depositional zones of a beach profile. The beach deposits are overlain disconformably by the Hensel Formation which contains basal fluviatile or estuarine clays updip and nodular caliche downdip, with locally associated calcareous dune(?) deposits.The sequence of festoon cross-beds overlain by planar cross-beds is the most significant key to recognition of beach deposits as well as reconstruction of geomorphic and geographic aspects of the depositional environment. Abundant orientation measurements from both types of cross-beds favor the interpretation that Cow Creek beach accretion originated in a shoreline re-entrant sheltered from the erosive influence of vigorous, southwesterly flowing longshore currents. Within this depositional regimen, coarse shell debris furnished by slackened currents was reworked by waves refracted against a curving shoreline and deposited as seaward-prograding planar cross-beds of a shifting foreshore zone. Beach pro-gradation apparently terminated just downdip from the outcrop area once the shoreline was stabilized by filling of the re-entrant. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.