Reconstructing the history of sediment deposition in caves: A case study from Wonderwerk Cave, South Africa

Research Article| March 01, 2012 Reconstructing the history of sediment deposition in caves: A case study from Wonderwerk Cave, South Africa A. Matmon; A. Matmon † 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel †E-mail: arimatmon@cc.huji.ac.il Search for other works by this author on: GSW Google Scholar H. Ron; H. Ron 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel Search for other works by this author on: GSW Google Scholar M. Chazan; M. Chazan 2Department of Anthropology, University of Toronto, 19 Russell Street, Toronto, Ontario M5S 2S2, Canada Search for other works by this author on: GSW Google Scholar N. Porat; N. Porat 3Israel Geological Survey, 30 Malkhe Israel Street, Jerusalem 95501, Israel Search for other works by this author on: GSW Google Scholar L.K. Horwitz L.K. Horwitz 4National Natural History Collections, Faculty of Life Science, Berman Building, The Hebrew University, Jerusalem 91904, Israel Search for other works by this author on: GSW Google Scholar Author and Article Information A. Matmon † 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel H. Ron 1Institute of Earth Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel M. Chazan 2Department of Anthropology, University of Toronto, 19 Russell Street, Toronto, Ontario M5S 2S2, Canada N. Porat 3Israel Geological Survey, 30 Malkhe Israel Street, Jerusalem 95501, Israel L.K. Horwitz 4National Natural History Collections, Faculty of Life Science, Berman Building, The Hebrew University, Jerusalem 91904, Israel †E-mail: arimatmon@cc.huji.ac.il Publisher: Geological Society of America Received: 12 Sep 2010 Revision Received: 24 Apr 2011 Accepted: 05 May 2011 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 © 2012 Geological Society of America GSA Bulletin (2012) 124 (3-4): 611–625. https://doi.org/10.1130/B30410.1 Article history Received: 12 Sep 2010 Revision Received: 24 Apr 2011 Accepted: 05 May 2011 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation A. Matmon, H. Ron, M. Chazan, N. Porat, L.K. Horwitz; Reconstructing the history of sediment deposition in caves: A case study from Wonderwerk Cave, South Africa. GSA Bulletin 2012;; 124 (3-4): 611–625. doi: https://doi.org/10.1130/B30410.1 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 We applied cosmogenic isotope burial dating, magnetostratigraphy, and grain-size distribution analysis to elucidate the history of the sedimentary sequence, composed of fine quartz sands and silts, of Wonderwerk Cave, located on the southern edge of the Kalahari Desert, South Africa. The source for the quartz sand is the Kalahari sand dunes, presently located ∼100 km to the north of the cave. Field observations and grain-size analysis suggest a sediment transport scenario that includes eolian transport of Kalahari sand, abraded to a size of 70–100 μm, to the Kuruman Hills, temporary storage on the hill slopes and valleys surrounding Wonderwerk Cave, and later transport and deposition inside the cave.Our results suggest simple burial ages for sediments from both the front and back of the cave that range between 2.63 ± 0.17 Ma and 1.56 ± 0.10 Ma following initial exposure of 310–620 k.y. However, 26Al/10Be ratios of 3.98 ± 0.24 and 4.08 ± 0.22 measured in a sand sample collected from the surface outside the cave may imply an initial burial signal equivalent to 0.78 ± 0.15 Ma, thus reducing the possible age range of the buried samples to between 1.85 ± 0.23 and 0.78 ± 0.18 Ma. The paleomagnetic results for the front of the cave gave a polarity sequence of N > R > N‖N, where N indicates normal polarity, and R indicates reverse polarity. This sequence can be correlated with both the older and younger cosmogenic burial age ranges. The correlation suggests that in the cave front, cosmogenic burial ages and the acquisition of stable remanent magnetization were not significantly affected by chemical and physical processes and that postburial production of cosmogenic isotopes was insignificant. In contrast, at the back of the cave, the paleomagnetic polarity sequence of R > N cannot be correlated with the cosmogenic burial ages, since the temporal gap between the initial penetration of the sediment into the cave and the final acquisition of a stable remanent magnetization may have been long (∼105 yr), and the single polarity transition can be correlated to any reverse-normal transition that occurred during the Quaternary. This highlights the need for caution when cosmogenic burial ages and paleomagnetic sequences are compared.The buried sediments in Wonderwerk Cave show similar grain-size distributions to the fine sand sediment presently exposed at the surface in the vicinity of the cave. Furthermore, calculated preburial 10Be concentrations for the buried sediment are similar to those measured in sediment outside the cave. These similarities suggest that the environmental conditions and rates of geomorphic processes that persisted during sand deposition in Wonderwerk Cave during the late Pliocene and early Pleistocene may have been similar to those currently experienced in the southern Kalahari, the Kuruman Hills, and the western Ghaap Plain. These conditions favor the transport of fine-grained quartz sand to the vicinity of the cave. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

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