1Evolutionary Studies Institute, University of the Witwatersrand, 2School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand
April 15, 2016 3:15, A 706/707
Sterkfontein is one of the most productive paleoanthropological sites in the world. Investigations in the Jacovec Cavern, one of Sterkfontein’s deepest chambers, were prompted by the discovery of an in situ Australopithecus sp. partial cranium. The site provides a rare opportunity to investigate well preserved, morphologically intriguing hominin fossils and stratigraphically associated fauna from a highly fossiliferous, discrete and in situ deposit. Previous works in the Jacovec Cavern provided initial hominid morphological descriptions from the original fossil and 11 ex situ specimens and placed them within a preliminary taphonomic, stratigraphic and chronological framework. This project applies high resolution sedimentological analyses (from thin sections, petrographic descriptions and facies analysis) and identifies four stratigraphic units documenting the long sequence of deposition in the cave. The units include a basal laminated, micaceous, carbonate-deficient silty mudstone erosionally overlain by a cherty gravelly horizon. These are overlain by laterally extensive, fossiliferous carbonate-rich breccias (an older ‘brown’ and younger ‘red’). Micromorphological clastic analysis has contributed greatly to our understanding of karst development at Sterkfontein, with the presence of ghost rock structures denoting the phreatic stages of the cavern and subsequent lithification and reworking of allogenic and autogenic sediments. The uppermost breccias indicate a primary deposition of locally sourced fossilifeous sediments represented by laterally extensive, correlatable deposits. These interpretations are contrasting to that of previous work by Partrigde et al. This study demonstrates the importance of high resolution sedimentary analyses in complex palaeoanthropological studies.
The authors would like to acknowledge the Palaeontological Scientific Trust, the Centre of Excellence (Palaeosciences), the National Research Foundation and the South African Department of Science and Technology.