Geoscience

CESD Program: New Contribution to Climate Change

The magazine Science published a paper titled “Glacial-interglacial Indian summer monsoon dynamics” as a research article by Prof. An Zhisheng (Institute of Earth Environment, CAS) and his colleagues on Aug. 5, 2011. Based on the 666-meter long lacustrine sediment core from Heqing paleolake at the southeastern edge of the Tibetan Plateau, the first drill core of the Chinese Continental Environmental Scientific Drilling (CESD) Program, a high-resolution multi-proxy record for Indian summer monsoon (ISM) during the Pleistocene (2.6 million years) was reconstructed. This record indicates that relatively small variability of ISM in the early and late Pleistocene can be regarded as the results of interactions between northern and southern hemisphere ice volumes, whereas in the middle Pleistocene, the relative large variability of ISM is dominantly controlled by the northern ice volume variations. The authors attribute the early increase of the ISM before global ice volume reaches a maximum to an increased cross-equatorial pressure gradient derived from the Southern Hemisphere high-latitude cooling. This mechanism explains much of the non-orbital scale variance in the Pleistocene ISM record. The Perspective of Science in the same issue commented “An analysis of ancient lake bed sediments challenges traditional views of Indian monsoon dynamics”. “This new insight into Indian summer monsoon is important for our understanding of global climate. It also highlights the potential influence of global warming on monsoon variability”, as highlighted by Nature China. The work has been jointly accomplished by the Chinese and American scientists from Institute of Earth Environment, CAS, Brown University, Nanjing Institute of Geography and Limnology, CAS, Research Institute for Global Change in Japan and the Xi’an Jiaotong University.

The 10th GSSP Defined in China

The Executive Bureau of the International Union of Geological Sciences (IUGS) has voted through the proposal submitted by the International Commission on Stratigraphy on establishing a Global Standard Stratotype-section and Point (GSSP) for the base of the Cambrian Jianghsanian Stage (named previously as provisional Cambrian Stage 9). The relevant ratification of IUGS, issued recently by Prof. A. C, Riccardi, President of IUGS, indicates that the GSSP is formally set up in Duibian Village, Jiangshan County, Zhejiang Province, China. The GSSP is the 10th “Golden Spike” set up in China, which makes China a country holding the largest number of GSSPs in the world. Previously, China, UK, and Italy each has nine GSSPs. The Jiangshanian Stage is named after the Jiangshan County, western Zhejiang Province, where the GSSP is located. It is a formal chronostratigraphical unit appeared in the International Stratigraphic Chart in succession of some other units (stages and Series) termed by the Chinese Scientists.