Heading north: Late Pleistocene environments and human dispersals in central and eastern Asia.

Michael Petraglia,Florian Ott,Xing Gao,Patrick Roberts,Nicole Boivin,Peter F. Biehl,Feng Li,Nils Vanwezer

doi:10.1371/journal.pone.0216433

Abstract

The adaptability of our species, as revealed by the geographic routes and palaeoenvironmental contexts of human dispersal beyond Africa, is a prominent topic in archaeology and palaeoanthropology. Northern and Central Asia have largely been neglected as it has been assumed that the deserts and mountain ranges of these regions acted as ‘barriers’, forcing human populations to arc north into temperate and arctic Siberia. Here, we test this proposition by constructing Least Cost Path models of human dispersal under glacial and interstadial conditions between prominent archaeological sites in Central and East Asia. Incorporating information from palaeoclimatic, palaeolake, and archaeological data, we demonstrate that regions such as the Gobi Desert and the Altai Mountain chains could have periodically acted as corridors and routes for human dispersals and framing biological interactions between hominin populations. Review of the archaeological datasets in these regions indicates the necessity of wide-scale archaeological survey and excavations in many poorly documented parts of Eurasia. We argue that such work is likely to highlight the ‘northern routes’ of human dispersal as variable, yet crucial, foci for understanding the extreme adaptive plasticity characteristic of the emergence of Homo sapiens as a global species, as well as the cultural and biological hybridization of the diverse hominin species present in Asia during the Late Pleistocene.

Highlights

While our results do not yet definitively demonstrate west to east routes of hominin dispersal, and the use of more detailed, high-resolution inter-stadial climate models will be required in the future to confirm their viability relative to ‘glacial’ period models, they do suggest that fieldwork and survey within the Altai Mountains, the Tian Shan Mountains, the Tarim Basin, and the Gobi Desert offer much potential to reveal Pleistocene insights into hominin dispersals
We suggest that the eastern edge of the Altai Mountain chain, the Tian Shan Mountain passes, and the Gobi and Taklamakan Deserts all warrant further survey in this regard, with a view to discovering additional, sites, recovering new chronological information, and evaluating the potential fossil affiliations and timing of the arrival of different toolkits in Central, northern, and eastern Asia
If we are to come to a better understanding of how the biological, cultural, and social evolutionary trajectories of Homo sapiens are intertwined, it is clear we need to develop high resolution palaeoenvironmental and palaeoecological models for our own species, as well as other contemporary or ancestral hominin populations, across the variety of regions they came to inhabit in the Late Pleistocene

Summary

Methods

A GIS approach provides a computational understanding of the best routes to travel across the vast region of Central, northern, and eastern Asia. Dates from the region suggest the earliest IUP appears during MIS3 These maps provide the ‘cost surfaces’ for the Least Cost Path analysis to determine the most effective route of this arrival. To create these cost surfaces, we first assembled spatial palaeolandscapes using topographic data overlain with modern and published palaeolake extents for the MIS3 model and LGM glacier extents and LGM precipitation estimates for the ‘glacial’ model. All the impermeable barriers were given the value of NoData All of these geographic factors were combined with the slope map to create a base palaeogeographic cost surface for the wet and dry models. They enable us to further test to the degree to which aridity would have limited movement across Central Asia under glacial conditions in MIS4

Results

Discussion

Conclusions

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