This study aims to reconstruct a detailed bioclimatic history of the last 50,000 years in the westerlies-dominated Central Asia based on a multi-proxy study of several thick eolian sections. The westerlies-dominated region includes the Dzungaria Basin (northwestern Xinjiang) and the Kazakhstan Hills and Plains (eastern Kazakhstan) that mark the conjunction between the East Asian Monsoon and the westerlies-dominated "European" climate systems. This investigation will produce paleoclimatic proxy records from a suite of loess/paleosol sections that span the past 50,000 years. A combination of geophysical, geochemical, and geobiological proxies will be used in the reconstruction. Bioclimatic transfer functions based on pollen, snails, carbon-13 of organic matter, and environmental magnetic parameters will be produced along three N-S transects to provide regional coverage of bioclimatic changes during the past 50,000 years.
A relatively high-resolution reconstruction of bioclimatic changes from eolian sequences in the study area shall provide a context for understanding hemispheric- and global-scale forcing mechanisms and ocean-atmosphere-continent couplings throughout the past 50,000 years. The bioclimatic reconstruction will permit a better understanding of not only the interacting history between the East Asian monsoons and the westerlies but also the teleconnections between the North Atlantic Oscillation (NAO) and the Pacific North American (PNA) Oscillation. The outcomes of this research will improve understanding of the land-air coupled feedback mechanisms and validate the hypothesis that atmospheric aerosol influx might have triggered global atmospheric CO2 changes. This project will enhance partnership possibilities in a global network of aerosol studies by establishing collaborations among international institutions (U.S., Kazakhstan, and China) and the reconstructed bioclimatic history will provide insight for combating the ongoing problem of human-exacerbated desertification in Central Asia.
