Holocene Paleoshoreline and Paleoenvironmental History of Palau: Implications for Human Settlement

ABSTRACT

Information from cores into the offshore reefs of Komebail Lagoon and into the coastal fringes of Babeldaob and neighboring islets allows the first well-constrained appraisal of the Holocene paleoshoreline history of Palau. Bulk subsidence of the island group since ∼5 kyr at a rate of ∼0.55 mm/yr is indicated jointly by both the offshore and the onshore datasets. Persistent subsidence of paleoshorelines since the initial human settlement of Palau has implications for the evolution of coastal paleoenvironments and the elevations of early coastal habitation sites with respect to present sea level. Discrepancies between radiocarbon dates for the earliest known archaeological sites and the earliest human impact on island environments in Palau and elsewhere in western Micronesia raise pointed questions about the timing of initial human occupation. Knowledge of the paleoshoreline history of Palau suggests that the disturbance indicators provide a more reliable guide to human arrival than the earliest settlement sites discovered to date.

Keywords:

• Babeldaob
• Micronesia
• Palau
• paleoenvironment
• paleoshorelines
• palynology
• reefs

ACKNOWLEDGEMENTS

The first author (WRD) owes a special debt to Vince Blaiyok of Airai for an expertly guided small-boat tour, extending over three full days, of shorelines on the Rock Islands between Babeldoab and Peleliu, and thanks Jacqueline Dickinson for assistance during geological fieldwork, both onshore and offshore. The second author (JSA) acknowledges the generous support of both the Palau National Communications Corporation and the U.S. Army Engineer District (Honolulu) for paleoenvironmental research conducted in collaboration with his colleague Jerome V. Ward under the auspices of the International Archaeological Research Institute, Inc., of Honolulu. Our investigations were conducted with the permission of the government of the Republic of Palau through its Bureau of Cultural Affairs. The unfailing assistance of many Palauans, including Vince Blaiyok, through extended periods of research is warmly appreciated. Jolie Liston also aided all our investigations, and Jim Abbott of Scigraphics prepared the figures. Revisions in response to reviews by Geoffrey Clark and E. L. Winterer improved the text.