Reconstruction of Asian monsoon using compound-specific isotope signals of aquatic and terrestrial biomarkers in Tibetan lake systems
Year: 2014
Type: dissertation
Abstract: The general aim of this thesis was the reconstruction of the Indian Ocean summer monsoon (IOSM) dynamics using compound-specific isotope signals of aquatic and terrestrial biomarkers in Tibetan lake systems. Monsoon winds and precipitation can be retraced using different proxies, indirect climate indicators, which reflect the environmental factors in a known way. To assure the proper application of compound-specific δD values as monsoon proxy, the biological origin of sedimentary n-alkanes, their source waters and climatic relevant parameters influencing the δD values have been investigated at the Tibetan Plateau. Moreover, the utility of GDGTs as additional paleoclimate proxy for the Monsoon reconstruction has been analyzed. Finally, the investigated proxies are applied to a long sediment core from Nam Co to reconstruct the monsoon-forced hydrological and environmental changes in the past 24 ka cal BP. In this thesis, the understanding of the environmental conditions influencing the δD values of aquatic and terrestrial n-alkanes as well as GDGTs in Tibetan lake systems could be improved. Consequently, the explanatory power of these proxies in paleo¬climate studies, particularly concerning Monsoon reconstructions, could be enhanced. Moreover, the first quantitative reconstructions could be accomplished at Nam Co. By applying these proxies to the Nam Co sediment core, the knowledge on monsoonal circulation patterns in the past could be enlarged and a more comprehensive reconstruction of the monsoon system could be established for the Quaternary period.
Author: Franziska Günther
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
SDG: Climate action
Open Access status: green
OpenAlex ID: W2408961215