by Steven M. Colman, Gerald H. Haug, Gerald H. Haug, Peter Molnar

We propose to conduct scientific drilling at Lake Qinghai (36°32’ to 37°15’ N, 99°36’ to 100°47’ E), China. Lake Qinghai (3194 m altitude, 4400 km2), on the northeastern margin of the Tibetan Plateau, is an outstanding, world-class site for obtaining high-resolution records of climate and environmental history at least back to Pliocene. A study of drill cores from the lake and the surrounding area are critical for understanding the climatic, ecological and tectonic evolution of this area, including the development of the East Asian monsoon system and its relationship to major global atmospheric circulation and the tectonic history of the Tibetan Plateau. A workshop, Scientific Drilling at Lake Qinghai on the northeastern Tibetan Plateau: Highresolution paleoenvironmental records of eastern Asia and their significance for global change, funded by ICDP, Chinese Academy of Sciences (CAS) and National Scince Foundation of China (NSFC), has been convened in October, 2003. Workshop recommendations on scientific objectives, site selections, drilling operations, core analysis, logistic strategy, anticipated results, and project management have been incorporated in this proposal. A 1100-km-long seismic survey covering the entire lake has been completed. The results indicate that the lake consists of the northern and southern sub-basins with continuous stratigraphic sequences implying stable sedimentary environment. At least 700 m unconsolidated sediments were detected in the depocenters of the southern sub-basin. We propose to obtain a series of cores in Lake Qinghai, ranging from 200 to 700 m long and having basal ages at least Pliocene, to be used both climatic and tectonic studies. Ideal high-resolution climatic records of Holocene and several glacial cycles can be obtained with several additional 5 and 50 m cores, respectively. The GLAD800 drilling system will be available fort his project in 2005. Ideal logistic and transportation conditions can be met in the Lake Qinghai areas. Provincial and local governments have expressed strong support to this project. Supplementary finacial supports could be obtained from CAS, NSFC and other agencies. This investigation will advance our understanding of the pattern and dynamics of East Asian Monsoon, Asian inland climate changes and their relationships to global climatic systems of the past. It will also address issues concerning the growth of Tibetan Plateau and its environmental effects. The project and its findings will improve our ability to predict future climate change and resulting consequences and contribute to sustainable development policy in western China.

• The sedimentary record of the Lake reflects a long climatic and tectonic history for this environmentally sensitive region. We plan to examine the sediment records of the lake, focusing on three time frames:1) the long, full record, which may extend through the Pliocene and into the late Miocene, thereby providing insight about the inter-relationship of tectonism and monsoon climate;
• 2) the last ca. 130,000 years, an interval encompassing the last full glacialinterglacial cycle;
• 3) the last 2000 years, when the influence of human activity on climate variation and environmental change becomes especially pronounced. In summary, the scientific objectives of the proposed drilling program are:
• 1) To obtain an improved understand ing of the late Cenozoic environmental history of the Lake Qinghai region and the development of the East Asian monsoon climate;
• 2) To understand the Late Cenozoic tectonic evolution of the Lake Qinghai basin and the growth of the northeastern margin of the Tibetan Plateau and its effects on regional climate; and 3) 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 East Asian monsoon system, prevailing Westerlies, and, ultimately, the evolution of global climate.

CESD, Climate Change, Eastern Asian Monsoon, Global Change, ICDP-2004/05, Lake Drilling, Lake Qinghai, P.r. China, Paleoclimatology, QINGHAI, Tibetan Plateau

Latitude: 36.81130556, Longitude: 100.1370833