Paleoenvironmental changes in Southern Patagonia during late Quaternary inferred from lake sediments of Laguna Potrok Aike, Argentina

• Main Author: Zhu, Jiayun
• Other Authors: Lehmkuhl, Frank, Schäbitz, Frank
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Publikationsserver der RWTH Aachen University 2015
• Subjects: info:eu-repo/classification/ddc/550; Paläoklima; Südamerika; Quartär; Seesediment; Stabiles Isotop; Geowissenschaften; stabile isotopes; paleoclimate; South America; lake sediments; Argentina; Patagonia; Southern Ocean; Antarc*; Antarctica; Ice Sheet
• Online Access: https://publications.rwth-aachen.de/record/460871; https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-145404%22

Southern Patagonia possesses a unique value for the assessment of the global paleoclimatic system, because it is the only continental mass intersecting the core of the Southern Hemisphere Westerlies (SHW), which could have played a crucial role in driving the global deglacial warming during the last glacial termination. Paleoclimatic archives in southern Patagonia provide also terrestrial linkage to the sediment records from the Southern Ocean and the ice cores from Antarctica. Despite the great importance, continuous paleoclimatic records in southern Patagonia are only available for the period from the last deglaciation onwards, because most study sites are located in the Andean region, which was covered by the immense Patagonian Ice Sheet during the last Glacial. This research gap is being bridged by interdisciplinary multiproxy investigations within the framework of the Potrok Aike maar lake sediment archive drilling project (PASADO). The project provides a lake sediment record reaching back more than 50,000 years taken from Laguna Potrok Aike, a deep maar lake located in semi-arid southern extra-Andean Patagonia (51°58' S, 70°23' W, 113 m a.s.l.). By using stable isotope analysis of sedimentary organic material, this thesis has investigated the PASADO sediment section ranging from 26,000 to 8500 cal. BP, covering the last glacial-interglacial transition, to provide paleoenvironmental evidences from southern extra-Andean Patagonia for a time period with dramatic climatic changes. The work presented in Chapter 2, employs stable isotope (δ13CTOC, δ15NTN) and elemental (TOC, TN) analyses of fine-grained (<200µm) bulk organic matter preserved in pelagic sediments to reconstruct the lacustrine primary productivity and nutrient supply. Furthermore, a unique proxy approach based on cellulose and bulk organic matter of handpicked aquatic moss remains is established to infer the past lake water δ18O (δ18Olw) (Chapter 3). The validity of this approach is determined by the highly significant correlation between δ18O ...