by Chengshan Wang, Hailiang Dong, Christian Koeberl

Knowledge of Cretaceous terrestrial climatic change is often at best fragmentary. We propose to conduct scientific drilling in the Cretaceous Songliao Basin (42 º25´-49 º23´N, 119º40´- 128º24´E), China, to recover a nearly complete Cretaceous terrestrial sedimentary record, as determined from basin-filling history. A study of the core will provide unique opportunities for the geosciences community to understand the response of terrestrial environment to geological events related to the carbon cycle and greenhouse climate change during Cretaceous, which would be of help to inform our understanding of modern global warming. In 2006 and 2007, two scientific coreholes were completed with total length of 2485.89 m and recovery ratio of 96.46%, covering the complete mid- to Upper Cretaceous strata (SK-I and SK-II program) in the basin, supported by Ministry of Science and Technology of China (MOST) and Daqing Oilfield. The workshop ” Terrestrial Scientific Drilling Project of Cretaceous Songliao Basin”, funded by ICDP, MOST, Daqing Oilfield and Ministry of Land and Resources of China (MLR), was convened in Daqing from August 28 to 30, 2007, to discuss the possibility of recovering the deeper strata (J/K boundary to ~Albian, SK-III) in the Songliao Basin. Workshop recommendations on scientific objectives, site selection, drilling operations, core analysis, logistic strategy, anticipated results, and project management of potential SK-III, have been incorporated into this proposal. We propose to obtain about 4500 m cores of Huoshiling to Quantou Formation (SK-III), to be combined with the existing SK-I, and -II to form the first nearly complete Cretaceous terrestrial sedimentary record in the world. This will provide excellent high resolution climate records of the terrestrial environment for the whole Cretaceous. The ZJ70D drilling system will be used in this project. Ideal logistic and transportation conditions exist in the drilling site areas. Provincial and local governments have expressed strong support for this project. Supplementary financial support will be obtained from MOST and MLR of China, National Science Foundation of China (NSFC), and other agencies. This investigation will advance our understanding of climate change in the Cretaceous greenhouse world, and its relationship to geological events relevant to carbon cycles. It will address important problems, such as the identification of important stratigraphic boundaries and marine-terrestrial correlation of stratigraphy, the reasons for the biotic response to the terrestrial environmental change, terrestrial response to Cretaceous oceanic anoxic events, formation of terrestrial petroleum source rocks and mechanisms for the Cretaceous magnetic Normal Super-Chron (CNS).

• The sedimentary record of the Cretaceous Songliao Basin reflects a long climatic and tectonic history of northeastern Asia. We plan to examine the sedimentary record of the basin, focusing on three time windows:
• 1) the Early Cretaceous;
• 2) mid-Cretaceous; and 3) Late to end of Cretaceous, based on boreholes SK-III, -II, and -I, respectively. In summary, the scientific objectives of the proposed drilling program are:
• 1) To identify important terrestrial stratigraphic boundaries such as J/T and K/T, and establish the marine- terrestrial correlation of stratigraphy in the Cretaceous Songliao Basin, as well as to form the basis for the marine- terrestrial correlation of climatic and environmental change;
• 2) To learn the reasons for the biotic response to terrestrial environmental change and deep biosphere (fossil DNA), such as the radiation of Jehol, Songhuajiang and Mingshui Biotas, and to explore the possibility of utilizing fossil DNA as a proxy for environmental change;
• 3) To document the local terrestrial response to the Cretaceous oceanic anoxic events and to understand formation of major terrestrial hydrocarbon source rocks in the Songliao Basin;
• 4) To characterize the Cretaceous magnetic Normal Super-Chron from the terrestrial record, in order to increase our understanding of the dynamics of the deep earth

China, Climate Change, Cretaceous, SONGLIAO, Songliao Basin, Terrestrial

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