Human settlement of East Polynesia earlier, incremental, and coincident with prolonged South Pacific drought

Sear, D. A. et al. (2020) Human settlement of East Polynesia earlier, incremental, and coincident with prolonged South Pacific drought. Proceedings of the National Academy of Sciences of the United States of America, 117(16), pp. 8813-8819. (doi: 10.1073/pnas.1920975117) (PMID:32253300) (PMCID:PMC7183181)

Abstract

The timing of human colonization of East Polynesia, a vast area lying between Hawai‘i, Rapa Nui, and New Zealand, is much debated and the underlying causes of this great migration have been enigmatic. Our study generates evidence for human dispersal into eastern Polynesia from islands to the west from around AD 900 and contemporaneous paleoclimate data from the likely source region. Lake cores from Atiu, Southern Cook Islands (SCIs) register evidence of pig and/or human occupation on a virgin landscape at this time, followed by changes in lake carbon around AD 1000 and significant anthropogenic disturbance from c. AD 1100. The broader paleoclimate context of these early voyages of exploration are derived from the Atiu lake core and complemented by additional lake cores from Samoa (directly west) and Vanuatu (southwest) and published hydroclimate proxies from the Society Islands (northeast) and Kiribati (north). Algal lipid and leaf wax biomarkers allow for comparisons of changing hydroclimate conditions across the region before, during, and after human arrival in the SCIs. The evidence indicates a prolonged drought in the likely western source region for these colonists, lasting c. 200 to 400 y, contemporaneous with the phasing of human dispersal into the Pacific. We propose that drying climate, coupled with documented social pressures and societal developments, instigated initial eastward exploration, resulting in SCI landfall(s) and return voyaging, with colonization a century or two later. This incremental settlement process likely involved the accumulation of critical maritime knowledge over several generations.

• Item Type: Articles
• Additional Information: The Explorers Club Exploration Fund Grant, Gilchrist Expedition Grant, and Royal Geographical Society (with the Institute of British Geographers) Monica Cole Grant assisted with travel to Samoa. Funding for Lake Emoatul research was provided by Natural Environment Research Council (NERC) Grant NE/N006674/1. Lake Lanoto‘o research was funded under a NERC Studentship (to J.D.H.). All radioisotope dating was undertaken by GAU-Radioanalytical. Radiocarbon dates were provided by NERC Awards 2004.0416, 1799.0414, and 1900.0415 and four by Direct-AMS, two funded by an Integrative Graduate Education and Research Traineeship Program on Ocean Change Mini Grant (to A. E. Maloney).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cisneros, Dr Malu
• Authors: Sear, D. A., Allen, M. S., Hassall, J. D., Maloney, A. E., Langdon, P. G., Morrison, A. E., Henderson, A. C. G., Mackay, H., Croudace, I. W., Clarke, C., Sachs, J. P., Macdonald, G., Chiverrell, R. C., Leng, M. J., Cisneros-Dozal, L.M., Fonville, T., and Pearson, E.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Proceedings of the National Academy of Sciences of the United States of America
• Publisher: National Academy of Sciences
• ISSN: 0027-8424
• ISSN (Online): 1091-6490
• Published Online: 06 April 2020
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Proceedings of the National Academy of Sciences of the United States of America 117(16): 8813-8819
• Publisher Policy: Reproduced under a Creative Commons License