Fast biostratinomic destruction of previously diagenized human bones: an explanation for a lagged bioarchaeological records in Patagonia

VAZQUEZ, ROMINA CLARA; ARCHUBY, FERNANDO; BÉGUELIN, MARIÉN

Evento virtual

Encuentro; TaphCon 2020; 2020

The Palaeontological Association

Human occupation in South America is recorded from 15100 to 16600 years BP. However, inNorthwestern Patagonia, the oldest open-air sites bearing human skeletal remains are ~4000years BP. Then, a low bioarchaeological signal characterizes the first 10000 years. Thebioarchaeological record in Northwestern Patagonia is characterized by burial sites. Hence,taphonomic history consists of a short biostratinomic period immediately after death,restricted to mortuary practices of corpse preparation, being diagenesis the main phase ofbone modification. In a sort of natural experiment, we studied bones naturally exposed toweathering after 4000 years of diagenesis, with control of the time they were in the (second)biostratinomy. Macroscopic and microscopic taphonomic analysis of 9074 bone remainsindicated a remarkable deterioration after only 5-6 years of exposure to weathering. Theresults revealed an enhanced negative impact of biostratinomic processes on previouslydiagenized bones, which helps to understand the low bioarchaeological signal recordedbefore the late Holocene. The fact that bones remain visible for little time before beingunrecognizable or eventually destroyed, and the low current population density of Patagonia,reduces the probability of finding the bioarchaeological record. Low density of early-middleHolocene human populations is part of the explanation as well.