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Preprints
https://doi.org/10.5194/egusphere-2023-2156
https://doi.org/10.5194/egusphere-2023-2156
25 Sep 2023
 | 25 Sep 2023

Holocene environmental and climate evolution of Central West Patagonia as reconstructed from lacustrine sediments of Meseta Chile Chico (46.5º S, Chile)

Carolina Franco, Antonio Maldonado, Christian Ohlendorf, A. Catalina Gebhardt, María Eugenia de Porras, Amalia Nuevo-Delaunay, César Méndez, and Bernd Zolitschka

Abstract. Holocene environmental changes in Patagonia were mostly shaped by unsteady ice-cover recession. Consequently, environmental reconstructions are largely based on discontinuous moraine chronologies from valley deposits. Here, we present a 3 m-long continuous sediment record recovered from Laguna Meseta (LME), a lake located on Meseta Chile Chico. Its altitude and location relative to the North Patagonian Icefield provide a unique opportunity to reconstruct the glacial history and the related environmental dynamics.

Our radiocarbon chronology constrains sedimentation to the last ~10,000 years and provides a minimum age for postglacial ice-free lacustrine conditions due to a westward retreat of the ice cap. Lacustrine productivity reached its maximum at the start of sedimentation and decreased afterwards. Between 5,500 and 4,600 cal yr BP, a major shift towards allochthonous sediment accumulation occurred, caused by an abrupt increase in clastic deposition from basaltic lithologies of the Meseta Chile Chico. This episode correlates with the precipitation-driven mid-Holocene glacier advance of Patagonian glaciers and suggests that conditions were colder/wetter on the Meseta Chile Chico at that time. After 4,600 cal yr BP these conditions continued to supply LME with clastic sediments until a stepped decrease around 900 cal yr BP. Thereupon, lacustrine productivity distinctly increased and stabilized around 300 cal yr BP. Our findings indicate that environmental conditions on Meseta Chile Chico were mainly controlled by precipitation variability during regional oscillations of the Southern Hemisphere Westerly Winds over the last 10 ka.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
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Journal article(s) based on this preprint

08 Apr 2024
Holocene environmental and climate evolution of central west Patagonia as reconstructed from lacustrine sediments of Meseta Chile Chico (46.5° S, Chile)
Carolina Franco, Antonio Maldonado, Christian Ohlendorf, A. Catalina Gebhardt, María Eugenia de Porras, Amalia Nuevo-Delaunay, César Méndez, and Bernd Zolitschka
Clim. Past, 20, 817–839, https://doi.org/10.5194/cp-20-817-2024,https://doi.org/10.5194/cp-20-817-2024, 2024
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The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
We present a continuous sedimentary Holocene lacustrine record from the Central West Patagonia....
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