Sedimentation and Accumulation of organic carbon in the Angola Basin and on Walvis Ridge: Preliminary results of Deep Sea Drilling Project Leg 75

摘要: Leg 75 investigated two periods of accumulation sediments rich in organic matter. In the Upper Cretaceous section, more than 200 beds gray or black shale and mudstone carbon (as much as 18%) are intercalated within a sequence red green mudstones that contain less 1% carbon. The 1 to 62 cm thick constitute 10% section 20 cores which they were recovered. Both turbiditic pelagic processes involved deposition these beds. A combination factors, including increased productivity warm saline bottom waters, probably resulted delicate balance between oxic anoxic conditions periodically favored preservation matter basinal sediments. Pliocene-Pleistocene thoroughly bioturbated, there is no evidence persisting anoxia overlying water spite high content These different both significant concentration (>2%, maximum 18%), but greater mass per unit volume solid sediment.