Trace elements in coastal Southa African speleothems as proxies for sea level change and distance to the coast 

• DOI: 10.5194/egusphere-egu24-12206
• Publication Date: 2024-03-08T23:32:02Z
• Authors: Kerstin Braun; Yuval Burstyn; Nathaniel Miller; Lawrence Edwards; Xianglei Li
• Keywords: TRACE (psycholinguistics); Sea-Level Change

The South African south coast is noteworthy for its rich record of archaeological sites. Cave deposits from the region first known evidence hunter-gatherers using marine food resources ~165 ka ago. Between ~110 and 65ka also preserves worn seashells, complex stone bone tools, shell beads decorated ochre ostrich eggshell. Such tools objects may be early examples items that required accumulation dissemination knowledge over several generations culture. But our understanding environmental climatic background evolution such milestones in human history still limited. Here we present Mg/Ca, Sr/Ca, Ba/Ca U/Ca records speleothems Pinnacle Point on coast. were measured by laser-ablation ICP-MS cover time interval between 88 58 ka. We compared new to a range global regional proxies gaussian-kernel based cross correlation analyses. To understand larger scale patterns included temperature change as well weathering river runoff/rainfall amount, coastal upwelling, orbital parameters/insolation. Our Mg/Ca show steep decrease at transition interglacial MIS 5 into glacial 4 general positive relation with sea level. therefore interpret them terms changing contributions spray caves trace element budget. changes are especially pronounced this area due wide gently sloping continental shelf. Sea level variations during deposition speleothem samples meant was ~500m 30 km distant caves. Sr/Ca only short near 5-4 followed higher values 4. This leads negative most whereas rainfall/weathering runoff varied. in-cave processes related water availability, Prior carbonate precipitation CO2 degassing redox overlying soils, respectively. Higher would associated drier conditions oxidizing soil. Following interpretation, indicate b a, wetter shift towards within distance means had variable access time. Variable climate soil oxidation availability vegetation composition. consistent use sites hunter-gatherers, however, people able adapt these changes.