Immediate propagation of deglacial environmental change to deep-marine turbidite systems along the Chile convergent margin

Anne Bernhardt*, Wolfgang Schwanghart, Dierk Hebbeln, Jan Berend W. Stuut, Manfred R. Strecker

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


Understanding how Earth-surface processes respond to past climatic perturbations is crucial for making informed predictions about future impacts of climate change on sediment fluxes. Sedimentary records provide the archives for inferring these processes, but their interpretation is compromised by our incomplete understanding of how sediment-routing systems respond to millennial-scale climate cycles. We analyzed seven sediment cores recovered from marine turbidite depositional sites along the Chile continental margin. The sites span a pronounced arid-to-humid gradient with variable relief and related sediment connectivity of terrestrial and marine environments. These sites allowed us to study event-related depositional processes in different climatic and geomorphic settings from the Last Glacial Maximum to the present day. The three sites reveal a steep decline of turbidite deposition during deglaciation. High rates of sea-level rise postdate the decline in turbidite deposition. Comparison with paleoclimate proxies documents that the spatio-temporal sedimentary pattern rather mirrors the deglacial humidity decrease and concomitant warming with no resolvable lag times. Our results let us infer that declining deglacial humidity decreased fluvial sediment supply. This signal propagated rapidly through the highly connected systems into the marine sink in north-central Chile. In contrast, in south-central Chile, connectivity between the Andean erosional zone and the fluvial transfer zone probably decreased abruptly by sediment trapping in piedmont lakes related to deglaciation, resulting in a sudden decrease of sediment supply to the ocean. Additionally, reduced moisture supply may have contributed to the rapid decline of turbidite deposition. These different causes result in similar depositional patterns in the marine sinks. We conclude that turbiditic strata may constitute reliable recorders of climate change across a wide range of climatic zones and geomorphic conditions. However, the underlying causes for similar signal manifestations in the sinks may differ, ranging from maintained high system connectivity to abrupt connectivity loss.

Original languageEnglish
Pages (from-to)190-204
Number of pages15
JournalEarth and Planetary Science Letters
Publication statusPublished - 1 Sept 2017


A. Bernhardt was funded by German Research Foundation (DFG) grant BE 5070/1-1. The German Federal Ministry of Education and Research (BMBF) provided financial support for R/V Sonne cruises 102, 156 and 161 (CHIPAL 03G0102A, PUCK 03G0156A, SPOC 03G0161A). Samples from GeoB cores were provided by the MARUM ? Center for Marine Environmental Sciences at the University of Bremen. We thank Gert-Jan Weltje for making the end-member algorithm available. Data presented in this study are available at Michael Clare and an anonymous reviewer provided constructive criticism that significantly improved the manuscript.

FundersFunder number
Center for Marine Environmental Sciences at the University of Bremen
Deutsche ForschungsgemeinschaftBE 5070/1-1
Bundesministerium für Bildung und ForschungSPOC 03G0161A, CHIPAL 03G0102A, PUCK 03G0156A
MARUM – Zentrum für Marine Umweltwissenschaften


    • Chile
    • connectivity
    • Last Glacial Maximum
    • sediment-routing system
    • signal propagation
    • turbidity currents


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