Lake Qinghai Scientific Drilling Project

An Zhisheng ,A Li ,Yougui Song ,Steven M Colman

doi:10.2204/iodp.sd.2.05.2006

An Zhisheng , A Li + Show 2 more

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https://doi.org/10.2204/iodp.sd.2.05.2006

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Abstract

on the northeastern margin of the Tibetan Plateau at an elevation of 3194 m (Fig.1). The lake is extremely sensitive to changes in climate because it lies in a critical transitional zone between the humid climate region controlled by the East Asian monsoon and the dry inland region affected by westerly winds. Three major atmospheric circulation systems affect its climate: (i) the winter monsoon, induced by Siberian high pressure and associated high-latitude ice cover; (ii) tropical moisture from low latitudes, carried by the East Asian summer monsoon; and (iii) climatic changes in the North Atlantic region, the effects of which are inferred to be transmitted via the westerlies. A study of drill cores from the lake and the surrounding area is critical for understanding the climatic, ecological, and tectonic evolution of the area, including the development of the East Asian monsoon system and its relationship to major global atmospheric circulation.Lake Qinghai occupies a closed tectonic depression, or piggy-back basin, on the upper plate of a major, active thrust fault. The basin is bound to the north by the Qilian Mountains, which constitute the northeastern margin of the Tibetan Plateau. The lake basin thus is intimately related to the active tectonics of the Tibetan Plateau. Seismic-reflection data show that the lake sediments are tectonically deformed in some parts of the basin and largely undeformed in other parts, where they should record at least the timing of regional tectonism. The seismic surveys indicate that the shallow lake is underlain by northern and southern sub-basins and that the southern sub-basin contains a continuous strati-graphic sequence of unconsolidated sediments more than 700 m thick. At an international workshop in Xining, People’s Republic of China in October 2003, the Qinghai Drilling Project was planned to obtain a series of cores from at least four different sites, penetrating 200–700 m into the lake sediment and possibly reaching Pliocene or older strata. Other sites with shallower penetrations of 5–50 m were planned to target specific high-resolution climatic intervals in the Holocene and last several glacial cycles. The overall scientific objec-tives of the project are listed below.

Highlights

At an international workshop in Xining, China in October 2003, the Qinghai Drilling Project was planned to obtain a series of cores from at least four different sites, penetrating [200–700] m into the lake sediment and possibly reaching Pliocene or older strata
To obtain an improved understanding of the late Cenozoic environmental history of the Lake Qinghai region and the development of the East Asian monsoon climate
To correlate Lake Qinghai environmental records with other regional and global paleoclimatic records to obtain a better understanding of the connection between regional climatic change, the development of the East Asian monsoon system, prevailing westerlies, and, the evolution of global climate

Summary

Introduction

To obtain an improved understanding of the late Cenozoic environmental history of the Lake Qinghai region and the development of the East Asian monsoon climate. Lake Qinghai in the People’s Republic of China covers 4400 km[2] on the northeastern margin of the Tibetan Plateau ,at an elevation of 3194 m (Fig. 1).

Results

Conclusion