Initial Results From a Multi-Proxy Investigation of a Core From the Southeast Basin of Lake Qinghai, China
Abstract
The Lake Qinghai Drilling Project (LQDP), under the auspices of the International Continental Drilling Program (ICDP) and the Chinese Academy of Science (CAS), aims to uncover past variations in Asia monsoon and climate, on both orbital and millennial time scales. To supplement that project with records of modern to Holocene sediments, in May/June 2007, we recovered a 3.55-m-long Uwitec sediment core (LQDP07-1A) and a 70-cm-long Mackereth core (LQDP07-7B) from the southeastern basin of Lake Qinghai, at the site of LQDP site 2. Radiocarbon dates indicate that these cores provide a record extending back to ca. 20 ka. Data from multi-proxy analysis including high resolution magnetic susceptibility, optical images, bulk density, XRF and X-ray radiographs (ITRAX X-ray Fluoresence Core Scanner), water content (freeze dried), grain size (Beckman Coulter), carbonate content (coulometry), and isotope analyses of carbonate and organic matter (EA-IRMS) provide clues from which to decipher past changes in regional climate and in the Asian monsoon system. Lithological and chemical proxies are yielding highly consistent records of distinct glacial and Holocene climatic features. The glacial period is characterized by fine-grained uniform medium grey mud with low calcium carbonate contents, whereas Holocene sediments are highly variable in both sedimentary facies and grain size, and are relatively high in carbonate. We are currently undertaking 3-cm pollen analyses for the Uwitec core, and will work to synthesize these results to unravel the climatic signals stored in Lake Qinghai sediments.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMPP21A1393L
- Keywords:
-
- 1051 Sedimentary geochemistry;
- 1845 Limnology (0458;
- 4239;
- 4942);
- 4239 Limnology (0458;
- 1845;
- 4942);
- 4914 Continental climate records;
- 4942 Limnology (0458;
- 1845;
- 4239)