Paleoceanographic and paleoclimate evolution of the Northwest Pacific Ocean from the late Miocene to present
The reconstruction of the climate evolution of the Northwest Pacific Ocean and the adjacent East Asian continent in the geological past has gained increasing interest in recent years. The area is today the most densely populated region on Earth and has enormous economic power and potential. In order to better evaluate the potential impact of future atmospheric greenhouse gas concentrations, rising global temperatures, and rising sea levels, exact climate reconstructions for phases in the geological past, whose boundary conditions were similar to what is expected for the future, are of utmost importance. The most recent analogues include the Miocene and Mid-Pliocene Warm Period. Using an organic-geochemical biomarker approach, this PhD thesis aimed at characterizing both the long-term (from the late Miocene to present) and shorter-term (on glacial-interglacial timescales) climatic and oceanographic variability in the Northwest Pacific Ocean. The results were placed into the context of already existing climate records from the Pacific and other regions of the globe in order to identify regional parallels and differences. In this context, one focus was set on the climate evolution and its impact on the paleoceanographic regime with respect to changes in the strength and flow pattern and latitudinal position of the two major western boundary currents of the North Pacific, the Kuroshio and Oyashio Currents. A second research question targeted the changes in the atmospheric circulation over the Asian continent associated with climate variability. Two cores drilled during different Integrated Ocean Drilling Program and International Ocean Discovery Program expeditions, respectively, were used as sedimentary archives, which allowed a detailed and continuous paleoclimate reconstruction for the last 8 and 4 million years, respectively.