154943 - Implications of anomalous relative sea-level rise for the peopling.pdf (2.71 MB)
Implications of anomalous relative sea-level rise for the peopling of Remote Oceania
journal contribution
posted on 2023-05-21, 15:48 authored by Sefton, JP, Kemp, AC, Engelhart, SE, Joanna EllisonJoanna Ellison, Karegar, MA, Charley, B, McCoy, MDBeginning ~3,500 to 3,300 y B.P., humans voyaged into Remote Oceania. Radiocarbon-dated archaeological evidence coupled with cultural, linguistic, and genetic traits indicates two primary migration routes: a Southern Hemisphere and a Northern Hemisphere route. These routes are separated by low-lying, equatorial atolls that were settled during secondary migrations ~1,000 y later after their exposure by relative sea-level fall from a mid-Holocene highstand. High volcanic islands in the Federated States of Micronesia (Pohnpei and Kosrae) also lie between the migration routes and settlement is thought to have occurred during the secondary migrations despite having been above sea level during the initial settlement of Remote Oceania. We reconstruct relative sea level on Pohnpei and Kosrae using radiocarbon-dated mangrove sediment and show that, rather than falling, there was a ~4.3-m rise over the past ~5,700 y. This rise, likely driven by subsidence, implies that evidence for early settlement could lie undiscovered below present sea level. The potential for earlier settlement invites reinterpretation of migration pathways into Remote Oceania and monument building. The UNESCO World Heritage sites of Nan Madol (Pohnpei) and Leluh (Kosrae) were constructed when relative sea level was ~0.94 m (~770 to 750 y B.P.) and ~0.77 m (~640 to 560 y B.P.) lower than present, respectively. Therefore, it is unlikely that they were originally constructed as islets separated by canals filled with ocean water, which is their prevailing interpretation. Due to subsidence, we propose that these islands and monuments are more vulnerable to future relative sea-level rise than previously identified.
Funding
Micronesia Conservation Trust
History
Publication title
Proceedings of the National Academy of Sciences of The United States of AmericaVolume
119Issue
52Article number
e2210863119Number
e2210863119Pagination
1-10ISSN
0027-8424Department/School
School of Geography, Planning and Spatial SciencesPublisher
Natl Acad SciencesPlace of publication
2101 Constitution Ave Nw, Washington, USA, Dc, 20418Rights statement
Copyright © 2022 the Author(s). Published by PNAS. This article is distributed under Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CC BY-NC-ND).https://creativecommons.org/licenses/by-nc-nd/4.0/Repository Status
- Open