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People chose the coast during the big chill

Excavations on South Africa’s southeast coast have uncovered evidence of persistent human occupations from the end of the last Ice Age 35,000 years ago.

Importantly, the scientists say, this includes the period of the Last Glacial Maximum, which lasted from 26,000 to 19,000 years ago, highlighting the complex transitions that were necessary to survive wide climate and environmental fluctuations.

Archaeological records from this globally cold and dry time are rare in southern Africa because of widespread movement as people abandoned increasingly inhospitable regions.

However, researchers involved with the Mpondoland Palaeoclimate, Palaeoenvironment, Palaeoecology, and Palaeoanthropology Project (P5) suspected that places with narrow continental shelves may preserve records of glacial coastal occupation and foraging.

Mpondoland (also known as Pondoland) includes a remote and largely unstudied section of South Africa’s “Wild Coast”. Here a part of the continental shelf is only 10 kilometres wide.

“The narrow shelf in Mpondoland was carved when the supercontinent Gondwana broke up and the Indian Ocean opened,” says Hayley Cawthra, from Nelson Mandela University. “When this happened, places with narrow continental shelves restricted how far and how much the coastline would have changed over time.”

Cawley and a multi-disciplinary international team have been excavating a rock shelter site known as Waterfall Bluff for the past five years.

“The work we are doing in Mpondoland is the latest in a long line of international and multidisciplinary research in South Africa revealing fantastic insights into human adaptations that often occurred at or near coastlines,” says Erich Fisher from Arizona State University in the US.

Waterfall Bluff from the ocean. Credit: Erich Fisher

“Yet, until now, no-one had any idea what people were doing at the coast during glacial periods in southern Africa. Our records finally start to fill in these longstanding gaps and reveal a rich, but not exclusive, focus on the sea.

“Interestingly, we think it may have been the centralised location between land and sea and their plant and animal resources that attracted people and supported them amid repeated climatic and environmental variability.”

To date their evidence – a variety of marine fish and shellfish remains – P5 researchers worked with South Africa’s iThemba LABS and the Centre for Archaeological Science at Australia’s University of Wollongong, developing what they say is one of the highest-resolution chronologies at a southern Africa Late Pleistocene site.

The findings are published in the journal Quaternary Research.

In a companion study, published in Quaternary Science Reviews, palaeobotanists and palaeoclimatologists used different lines of evidence to investigate interactions between prehistoric people’s plant-gathering strategies and climate and environmental changes over the last glacial / interglacial phase.

It was the first multiproxy study in South Africa to combine preserved plant pollen, plant phytoliths, macro botanical remains (charcoal and plant fragments) and plant wax carbon and hydrogen isotopes from the same archaeological archive.

“It is not common to find such good preservation of different botanical remains, both of organic and inorganic origin, in the archaeological record,” says research leader Irene Esteban, from South Africa’s University of the Witwatersrand.

One of the key findings, the researchers say, is that Mpondoland’s current vegetation types persisted across glacial and interglacial periods, albeit in varying amounts due to changes in sea levels, rainfall and temperature.

The implication is that people living in the area in the past had access to an ever present and diverse suite of resources that let them survive here when they couldn’t in many other places across Africa.