Early Jurassic sedimentation of a rift-valley lake: Culpeper basin, northern Virginia

Research Article| January 01, 1985 Early Jurassic sedimentation of a rift-valley lake: Culpeper basin, northern Virginia TUCKER F. HENTZ TUCKER F. HENTZ 1Bureau of Economic Geology, The University of Texas at Austin, University Station, Box X, Austin, Texas 78713 Search for other works by this author on: GSW Google Scholar Author and Article Information TUCKER F. HENTZ 1Bureau of Economic Geology, The University of Texas at Austin, University Station, Box X, Austin, Texas 78713 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1985) 96 (1): 92–107. https://doi.org/10.1130/0016-7606(1985)96<92:EJSOAR>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 Email Permissions Search Site Citation TUCKER F. HENTZ; Early Jurassic sedimentation of a rift-valley lake: Culpeper basin, northern Virginia. GSA Bulletin 1985;; 96 (1): 92–107. doi: https://doi.org/10.1130/0016-7606(1985)96<92:EJSOAR>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 Gray, calcareous, lacustrine strata of Early Jurassic age crop out adjacent to the faulted western margin of the Culpeper basin, a Mesozoic graben dominated by fluviogenic red beds. Sedimentological, mineralogical, and paleontological aspects reveal a distinct zonation of littoral, sublittoral, and profundal deposits in the lacustrine sequence. Reconstructed physiographic profiles of the lake exhibit shore-terrace, slope, and basin-plain subenvironments. Dominant sedimentary processes in these domains were, respectively, sediment agitation by waves; deposition from suspension, slumping, and proximal sediment gravity flows; and suspension and distal turbidity current deposition. Deposition of the lacustrine sediments occurred in a eutrophic, calcite-precipitating, permanently or normally stratified lake.The lake occupied an elongate, actively subsiding sub-basin adjacent to, or possibly straddling, the western border fault. The sedimentary fill of the sub-basin is characterized by several cyclic fluvio-lacustrine sequences which average 150 m in thickness and closely resemble sedimentary cycles of other Newark rift basins. The maximum areal extent of the lake may have exceeded 3,000 km2, with an average maximum depth of ∼35 m. Proterozoic and lower Paleozoic strata of the Blue Ridge anticlinorium to the west constituted the major source of clastic sediments in the lacustrine sequence, but uptilted basalt flows and interbedded sedimentary units of the Culpeper Group simultaneously shed detritus from the east. 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.