Uranium-series dating of the draining of an aquifer: The example of Wind Cave, Black Hills, South Dakota

Abstract

Research Article| February 01, 1993 Uranium-series dating of the draining of an aquifer: The example of Wind Cave, Black Hills, South Dakota D. C. FORD; D. C. FORD 1Department of Geography, McMaster University, Hamilton, Ontario, Canada L8S 4K1 Search for other works by this author on: GSW Google Scholar J. LUNDBERG; J. LUNDBERG 1Department of Geography, McMaster University, Hamilton, Ontario, Canada L8S 4K1 Search for other works by this author on: GSW Google Scholar A. N. PALMER; A. N. PALMER 2Department of Earth Sciences, State University College, Oneonta, New York, New York 13820-4015 Search for other works by this author on: GSW Google Scholar M. V. PALMER; M. V. PALMER 2Department of Earth Sciences, State University College, Oneonta, New York, New York 13820-4015 Search for other works by this author on: GSW Google Scholar W. DREYBRODT; W. DREYBRODT 3Institut für Experimentelle Physik, Universitädt Bremen, D-2800 Bremen 33, Germany Search for other works by this author on: GSW Google Scholar H. P. SCHWARCZ H. P. SCHWARCZ 4Department of Geology, McMaster University, Hamilton, Ontario, Canada L8S 4K1 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1993) 105 (2): 241–250. https://doi.org/10.1130/0016-7606(1993)105<0241:USDOTD>2.3.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 D. C. FORD, J. LUNDBERG, A. N. PALMER, M. V. PALMER, W. DREYBRODT, H. P. SCHWARCZ; Uranium-series dating of the draining of an aquifer: The example of Wind Cave, Black Hills, South Dakota. GSA Bulletin 1993;; 105 (2): 241–250. doi: https://doi.org/10.1130/0016-7606(1993)105<0241:USDOTD>2.3.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 Wind Cave, South Dakota, is a three-dimensional, rectilinear maze cave developed in 90 m of Mississippian limestone and dolomite that is overlain by thick clastic cover strata. Beneath an area of 1.8 km2, 87 km of small, drained, phreatic passages are known. Exploration terminates at a water table 160 m below the highest parts of the cave. As the cave was draining, calcite precipitated from its waters.Uranium-series measurements (85) were taken on fragments of broken calcite crusts collected in the lower 93 m of the cave. The measurements reveal that it has been draining as a backwater for at least the past 300,000 yr. 234U/238U ratios in the water were remarkably constant, allowing estimation of ages beyond 400 ky B.P.After deducting glacial-interglacial cyclic oscillations (of 10- to 20-m amplitude), the water table appears to have been lowered at a steady rate of 0.4 m per 103 yr since ≥400 ky B.P. Most of this fall is attributed to the increase of hydraulic conductivity in the ~260 m of cover strata that separates the carbonate aquifer from its spring discharge points. A subaqueous calcite deposition zone extended to ~70 m below the contemporary water table at all times, where mean rates of deposition were 0.12 mm per 103 yr or less. Modeling of the precipitation kinetics suggests a well-mixed water body, with a Ca2+ concentration close to the thermodynamic equilibrium value and variations of depositional rate being controlled by hydrostatic pressure. 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.