Holocene relative sea-level change along the tectonically active Chilean coast ; Quaternary Science Reviews

Abstract

We present a comprehensive relative sea-level (RSL) database for north, central, and south-central Chile (18.5 degrees S - 43.6 degrees S) using a consistent, systematic, and internationally comparable approach. Despite its latitudinal extent, this coastline has received little rigorous or systematic attention and details of its RSL history remain largely unexplored. To address this knowledge gap, we re-evaluate the geological context and age of previously published sea-level indicators, providing 78 index points and 84 marine or terrestrial limiting points spanning from 11 ka to the present day. Many data points were originally collected for research in other fields and have not previously been examined for the information they provide on sea-level change. Additionally, we describe new sea-level data from four sites located between the Gulf of Arauco and Valdivia. By compiling RSL histories for 11 different regions, we summarise current knowledge of Chilean RSL. These histories indicate mid Holocene sea levels above present in all regions, but at highly contrasting elevations from similar to 30 m to <5 m. We compare the spatiotemporal distribution of sea-level data points with a suite of glacial isostatic adjustment models and place first-order constraints on the influence of tectonic processes over 10(3)-10(4) year timescales. While seven regions indicate uplift rates <1 m ka(-1), the remaining regions may experience substantially higher rates. In addition to enabling discussion of the factors driving sea-level change, our compilation provides a resource to assist attempts to understand the distribution of archaeological, palaeoclimatic, and palaeoseismic evidence in the coastal zone and highlights directions for future sea-level research in Chile. (C) 2020 Elsevier Ltd. All rights reserved. ; European Union/Durham University (COFUND under the DIFeREns 2 scheme); Millennium Nucleus CYCLO "The Seismic Cycle Along Subduction Zones" - Millennium Scientific Initiative (ICM) of the Chilean Government [NC160025]; FONDECYT (Chile)Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [1190258]; US National Science Foundation (NSF)National Science Foundation (NSF) [EAR-1566253, EAR-1624795, EAR-1624533]; National Geographic Society (US)National Geographic Society [8577-08]; NSFNational Science Foundation (NSF) [EAR-1036057, EAR-1145170, EAR1624542]; Deutsche Forschungsgemeindschaft GrantGerman Research Foundation (DFG) [JA 2860/1-1]; International Geoscience Programme (IGCP) project [639] ; Published version ; EG undertook this work while in receipt of funding from the European Union/Durham University (COFUND under the DIFeREns 2 scheme). The authors acknowledge financial support from the Millennium Nucleus CYCLO "The Seismic Cycle Along Subduction Zones" funded by the Millennium Scientific Initiative (ICM) of the Chilean Government Grant Number NC160025. Additional support for MC and DM was provided by FONDECYT (Chile), project No 1190258. TD was supported by the US National Science Foundation (NSF) awards EAR-1566253, EAR-1624795, and EAR-1624533. LE was supported by National Geographic Society (US) Research Grant 8577-08 and NSF awards EAR-1036057, EAR-1145170, and EAR1624542. JJM was supported by the Deutsche Forschungsgemeindschaft Grant JA 2860/1-1. The authors acknowledge PALSEA (a PAGES/INQUA working group) and HOLSEA (an INQUA project) for useful discussions at the 2019 meeting, Dublin, Ireland. We thank Nicole Khan and Matteo Vacchi for their constructive reviews. This is a contribution to International Geoscience Programme (IGCP) project 639. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. ; Public domain authored by a U.S. government employee