PP042-08
Human settlements and climatic changes in Remote Oceania over the last millennium: Multi-proxy records from Vanuatu

Tuesday, 15 December 2020: 05:51
Virtual
Giorgia Camperio1,2, S. Nemiah Ladd1,3, Matthew Prebble4, Christiane Krentscher2, Amicie Delahaie2,5 and Nathalie Dubois1,2, (1)ETH Swiss Federal Institute of Technology Zurich, Earth Science, Zurich, Switzerland, (2)EAWAG Swiss Federal Institute of Aquatic Science and Technology, Surface Waters - Research and Management, Duebendorf, Switzerland, (3)University of Freiburg, Ecosystem Physiology, Freiburg, Germany, (4)Australian National University, Department of Archaeology and Natural History, Canberra, Australia, (5)Ecole Normale Supérieure Paris, Department of Chemistry, Paris, France
Abstract:
Remote Oceania comprises hundreds of islands, which today are inhabited by hundreds of thousands of people. Changes in precipitation are the main climatic signal in the area and are influenced by the South Pacific Convergence Zone (SPCZ), a band of rain that moves zonally. The human colonization of this area of the Pacific Ocean is considered the last great migration of our species, which occurred ~3000 years ago. This is attributed to the Lapita people, a population coming from South East Asia. Shifts in the SPCZ might have influenced the colonization of the islands and the establishment of agriculture.

The archipelago of Vanuatu, which is located at the western edges of the SPCZ and hosts rich archeological remains, is an ideal place to study past landscape modifications driven by climatic changes and human presence, and their interactions.

Here, we present sedimentological records from two small lakes located on the west coast of Espiritu Santo, the largest island in Vanuatu, spanning the last millennium. We apply a multi-proxy approach combining fossil molecules of known origin with sedimentological and paleoecological proxies.

A high-resolution age model from radiocarbon-dated terrestrial macrofossils allows for a detailed reconstruction of past environmental changes in this remote area. Changes and down-core covariations in fecal markers, pollen and charcoal, biogenic silica, total organic carbon, and the compound-specific isotopic composition of fatty acids indicate different phases and events characterizing the catchments including the anthropogenic origin of the lakes, the establishment of agriculture, the arrival of Europeans, and variations in the climatic signals.

This multi-proxy reconstruction highlights the tight interaction between humans and the environment in shaping current landscapes and the key factors responsible for the changes occurring in these vulnerable ecosystems.

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