Abrupt increase of calcium carbonate contents in the Campbell Plateau (SW Pacific Ocean) during the deglaciation

摘要

A core taken from a mudline of Hole 1120A (ODP Leg 181) located in the Campbell Plateau, Southwest Pacific Ocean documents the deglacial variation of calcium carbonate contents. Stable isotope profiles of planktonic and benthic foraminifera and a radiocarbon AMS dating (11,260 ka) constrain the age of deglaciation. Abrupt increase in the calcium carbonate contents during the deglaciation is a result of complex combination of dissolution, production, and dilution. Dissolution of bottom water plays insignificant role in Site 1120 due to the bathymetric high site above the present lysocline. The reduction in dilution of noncarbonate terrigenous particles is considered as a major reason to show the enhanced calcium carbonate contents during the Holocene. Such chalk-marl cycle of Atlantic-type carbonate variation can be observed in the Southwest Pacific Ocean.