Cave life histories of non-anthropogenic sediments help us understand associated archaeological contexts

Pinnacle Point (PP) near Mossel Bay in the Western Cape Province, South Africa, is known for a series of archaeological caves with important archaeological finds. Extensive excavations and studies in two of them (PP13B and PP5-6) have documented alternating periods of anthropogenic-dominated and geogenic-dominated sedimentation. A variety of caves do not bear evidence of anthropogenic remains. We have studied in detail the remnant deposits of three of them, Staircase Cave, Crevice Cave, and PP29, which have been formed under the same geologic and sedimentary conditions with those with anthropogenic contributions. Their remains are small and patchy but have extensive speleothem formations (as do most caves at PP) that were isotopically analyzed for paleoclimate and paleoenvironmental reconstruction. These caves also offer the opportunity to understand the purely geogenic signature of the PP locality and thus offer a geogenic baseline for the anthropogenic caves. Archaeologists normally focus only on sites with strong anthropogenic signals, but by building cave life histories we “raise the bar” (Goldberg 2008, p. 30) on our contextual knowledge.