Progresses of ocean drilling in Bengal Fan: Scientific issues and drilling prospect

The Bengal Fan is not only a source-sink transition zone connecting the plateau and the deep sea, but also an important product of plates drift and collision. Its deep sedimentary records are the natural archives of the India-Eurasia plate collision, the uplift and erosion process of the Qinghai Tibet Plateau and the evolution of climate and environment. We summarized the drilling expeditions and the latest research progress focusing on the sedimentary process and climate evolution since the late Miocene, the nature and evolution of the 90°E Ridge, and the formation of the South Asian monsoon in the Bengal Fan. However, constrained by drilling capacity and scientific targets, the full time sedimentary strata, the age and structural characteristics of the underlying oceanic crust in the Bengal Fan have not been effectively revealed which hinders the research on the long-time scale source to sink transition, the South Asia Mosoon formation and plate reconstruction. Based on the recently acquired high-quality multi-channel seismic data, the basement fluctuation, sedimentary structure and tectonic development characteristics of the Bengal Fan downstream are interpreted. Furthermore, we proposed three future scientific drilling locations which aim at the scientific drilling objectives including the complete sedimentary strata, age of oceanic crust basalt, and special structure characteristics. Well calibration and lithology prediction are carried out for these proposed drillings respectively. These proposed drillings are not only contributed to the reserve of scientific drilling for Chinese Ocean Drilling Vessel, but also significant for solving the frontier scientific issues of the Qinghai Tibet Plateau.