Cave and rock shelter sediments of southern Africa: a review of the chronostratigraphic and palaeoenvironmental record from Marine Isotope Stage 6 to 1

Caves and rock shelters contribute important records to local, regional and sub-continental reconstructions of environment and climate change through the southern African Quaternary. Against a backdrop of pronounced climate change, the archaeological record of the Marine Isotope Stage 6 to 1 period in southern Africa documents a remarkable time in the behavioural and technological evolution of anatomically modern humans. Significant evidence of this evolution is represented in diverse components of the sedimentary record in caves and rock shelters in the region. We present a catalogue of published caves and rock shelters in southern Africa that preserve temporally-relevant clastic and chemical palaeoclimatic proxies in order to: (1) facilitate the integration of cave and rock shelter sedimentary data into broader, regional chronostratigraphically-correlated palaeoclimatic sequences; and (2) identify possible areas and proxies that require focused research in the future. To demonstrate the complexity of the Marine Isotope Stage 6 to 1 stratigraphic record and use of palaeoenvironmental proxies, we present three case studies representing interior and coastal contexts: Border Cave, Klasies River Mouth and Pinnacle Point. These examples aptly demonstrate the challenges of these contexts, but also the opportunities for palaeoenvironmental research in southern Africa when conducted through integrated, multidisciplinary approaches. Published records of palaeoenvironmental research from cave and rock shelter sequences in southern Africa are heavily biased to the South African coastal areas and the record is temporally and spatially fragmented. However, there are interesting patterns in the chronostratigraphic record and in the distribution of sites within the context of the geology and vegetation ecology of southern Africa that require further exploration. There are also promising techniques in stable isotope analysis that can be applied to abundant sedimentary components found in the region’s caves and rock shelters, and in its museums.

Phytolith Palaeoenvironments at Mumba Rock Shelter

The rock shelter site of Mumba in northern Tanzania plays a pivotal role in the overall study of the late Pleistocene archaeology of East Africa with an emphasis on the Middle to Later Stone Age transition. We used phytolith analysis to reconstruct general plant habitat physiognomy around the site from the onset of the late Pleistocene to recent times, tallying 4246 individual phytoliths from 19 archaeological samples. Statistical analysis explored phytolith richness, diversity, dominance, and evenness, along with principal components to compare phytolith distributions over the site’s sequence with known plant habitats today. Generally, the phytolith record of Mumba signifies paleoenvironments with analogs in the Somalia – Masai bushland and grassland, as well as Zambezian woodlands.

New AMS Radiocarbon Ages from the Preceramic Levels of Coxcatlan Cave, Puebla, Mexico: A Pleistocene Occupation of the Tehuacan Valley?

Archaeological studies at Coxcatlan Cave in the Tehuacan Valley of southern Puebla, Mexico, have been instrumental to the development of the chronology for the region and for our understanding of the origins of food production in the Americas. This article refines the Preceramic chronology of the Tehuacan Valley by presenting 14 new accelerated mass spectrometry (AMS) radiocarbon ages from faunal bone samples uncovered from early depositional levels of the rock shelter. Although bones associated with the El Riego (9893–7838 cal BP), Coxcatlan (7838–6375 cal BP), and Abejas (6375–4545 cal BP) phase zones of the cave yielded ages similar to those of the previously proposed chronology for the region, bones from the Ajuereado phase zones at the base of the cave yielded surprisingly old ages that range from 33,448 to 28,279 cal BP, a time prior to the Last Glacial Maximum. Because these early ages are many thousands of years older than current models estimate for the peopling of the Americas, they require reassessments of the artifacts and ecofacts excavated from these early zones.