Characterizing the Meghalayan Stage in southern Africa: A multiproxy record of paleoenvironmental change at the southern margin of the Kalahari

Abstract

Abstract In this study we investigate the timing and nature of moisture availability in the Late Holocene by examining a multiproxy paleoenvironmental record from Kathu Pan at the southern edge of the Kalahari. In a region where organic proxy records are scarce, Kathu Pan provides a unique record of changes in past environmental conditions. Pollen, spore, charcoal, and stable isotope records were obtained from organic deposits at Kathu Pan and examined within a radiocarbon-constrained chronological framework. The Kathu Pan record registers a relatively moist phase occurring between 4.8 ka and 2.5 ka cal BP. Local environmental conditions at Kathu Pan shift gradually beginning around the terminal Northgrippian ~4.8 ka cal BP. Kathu Pan reaches maximum moisture availability with marsh-like conditions signaled by increased organic content, dominance of Cyperaceae pollen, presence of freshwater fungi, and δ13C values consistent with local C3 vegetation, around the inception of the Meghalayan Stage, although due to uncertainties in the age-depth model these changes may have taken place 1–2 centuries on either side of the formal date for the onset of the Meghalayan at 4.2 ka cal BP. This interval also corresponds with the highest charcoal concentrations, indicating the importance of adequate moisture conditions to support the growth of biomass which eventually becomes a fuel source. The moist phase lasts ca. 2000 years until a hypothesized shift to arid conditions occurs c. 2.5 ka cal BP leading to a change in local hydroclimate that may have terminated the accumulation of organic-bearing sediments.