Deglacial environmental changes on Isla de los Estados (54.4°S), southeastern Tierra del Fuego

The island of Isla de los Estados is situated at 54.5 degrees S, 64 degrees W, east of Argentinian Tierra del Fuego, and is located in a sensitive geographic position in relation to the zonal circulation between Antarctica and South America. Its terrestrial records of the last deglaciation, recordin...

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Bibliographic Details
Published in:Quaternary Science Reviews
Main Authors: Unkel, Ingmar, Björck, Svante, Wohlfarth, Barbara
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2008
Subjects:
Geology
LAGUNA POTROK-AIKE
LAST GLACIAL PERIOD
CAL KYR BP
HOLOCENE CLIMATE
BIPOLAR SEESAW
ICE-CORE
LACUSTRINE
GREENLAND
ATLANTIC SECTOR
RECORD
SOUTHERNMOST SOUTH-AMERICA
Antarctic
Greenland
The Antarctic
Antarc*
Antarctica
Ice
ice core
permafrost
Tierra del Fuego
Online Access:https://lup.lub.lu.se/record/1411417
https://doi.org/10.1016/j.quascirev.2008.05.004
Description
Summary:The island of Isla de los Estados is situated at 54.5 degrees S, 64 degrees W, east of Argentinian Tierra del Fuego, and is located in a sensitive geographic position in relation to the zonal circulation between Antarctica and South America. Its terrestrial records of the last deglaciation, recording atmospheric conditions but within an oceanic setting, can help to clarify changes of regional circulation patterns, both atmospheric and marine. Here, we present geochemical analyses from 16-10 ka cal BP of a peat core from Lago Galvarne Bog at the northern coast of the island, and a lake sediment core from Laguna Cascada 3 kin further south. The data comprise TC, TN, loss on ignition analyses and continuous XRF scanning on both cores as well as age-depth modeling based on AMS-C-14 dating. Deglaciation and onset of peat formation in the coastal areas began before 16 ka cal BP followed by a rapid glacial retreat and the start of lacustrine sedimentation further inland. Data Suggest initially windy conditions with permafrost succeeded by gradually warmer and wetter conditions until ca 14.5 ka cal BP. The warming trend slows down until ca 13.5 ka cal BP, followed by arid conditions culminating around 12.8 ka cal BP. Our data suggest fairly warm conditions and the establishment of denser peat and forest vegetation ca 10.6 ka cal BP, contemporaneous with the onset of the Antarctic thermal optimum. This indicates large-scale shifts in the placement of zonal flow and the Westerlies at the beginning of the Holocene. (C) 2008 Elsevier Ltd. All rights reserved.

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