Unraveling sea-level variations and tectonic uplift in wave-built marine terraces, Santa Maria Island, Chile

Jara-Munoz, Julius; Melnick, Daniel

Abstract

The architecture of coastal sequences in tectonically-active regions results mostly from a combination of sea-level and land-level changes. The objective of this study is to unravel these signals by combining sequence stratigraphy and sedimentology of near-shore sedimentary sequences in wave-built terraces. We focus on Santa Maria Island at the south-central Chile margin, which hosts excellent exposures of coastal sediments from Marine Isotope Stage 3. A novel method based on statistical analysis of grain-size distributions coupled with fades descriptions provided a detailed account of transgressive-regressive cycles. Radiocarbon ages from paleosols constrain the chronology between >53 and similar to 31 cal ka BP. Because the influence of glaciations can be neglected, we calculated relative sea-level curves by tying the onset of deposition on a bedrock abrasion platform to a global sea-level curve. The observed depositional cycles match those predicted for uplift rates between 1.2 and 1.8 m/ka. The studied sedimentary units represent depositional cycles that resulted in reoccupation events of an existing marine terrace. Our study demonstrates wave-built marine terrace deposits along clastic shorelines in temperate regions can be used to distinguish between tectonic uplift and climate-induced sea-level changes. (C) 2014 University of Washington. Published by Elsevier Inc. All rights reserved.

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Título según WOS: ID WOS:000349276300018 Not found in local WOS DB
Título de la Revista: QUATERNARY RESEARCH
Volumen: 83
Número: 1
Editorial: CAMBRIDGE UNIV PRESS
Fecha de publicación: 2015
Página de inicio: 216
Página final: 228
DOI:

10.1016/j.yqres.2014.10.002

Notas: ISI