Spatial Distribution of Contourites in Global Ocean and Its Paleoclimatic SignificanceThe Contribution of International Ocean Drilling to the Studies of Contourites
Contourite is one of the most important type of sediments in the global ocean,which has recorded significant information on paleoclimatic changes. It is also of great importance for ocean engineering and marine hydrocarbon exploration. The development of scientific ocean drilling,especially theIntegrated Ocean Drilling Program and the undergoingInternational Ocean Discovery Program,has made great contribution in mapping the spatial distribution of contourites and revealing contourite-related paleoclimatic information,through coring and geophysical exploration in the global ocean. It is found that the global distribution of contourites is controlled predominantly by the global deep-water circulation while its distribution in a specific region can be affected by the intensity of deep currents,tectonic activities,sediment supply,and so on. The geological changes in the global deep-water circulation is,however,further affected by tectonic activities,origins of water masses,as well as climate changes, e.g. the Cenozoic global cooling,changes in the size of the northern hemisphere ice caps,and intensity of monsoon. The main controlling factors of deep water circulation vary with different regions.