Orbital-scale CaCO3 and opal deposition in the central equatorial Pacific Ocean during the last 600 kyr

Abstract

Orbital-scale variations in biogenic silica CaCO3 and opal abundance of two piston cores (PC5101 from the southern (2N) site and PC5103 from the northern (6N) site) collected in the central equatorial Pacific Ocean were compared. The average model for core PC5103, which extends to about 950 ka, was developed by comparing the oxygen isotope stratigraphy of planktonic foraminifera (N. dutertrei) to the LR04 stacks. The age model for core PC5101, which extends to about 650 ka, was judged by stratigraphic correlation of CaCO3 contents to core PC5103 and contrained also by the well-dated core RC11-210. Distinct orbital-scale series of CaCO3 and opal variations are apparently parallel between the two cores, which are mainly controlled by an eccentricity with an approximately 100-kyr periodicity. However, the patterns of biogenic CaCO3 and opal deposition between the interglacial and glacial periods are different at the two cores.e model for core PC5103, which extends to about 950 ka, was developed by comparing the oxygen isotope stratigraphy of planktonic foraminifera (N. dutertrei) to the LR04 stacks. The age model for core PC5101, which extends to about 650 ka, was judged by stratigraphic correlation of CaCO3 contents to core PC5103 and contrained also by the well-dated core RC11-210. Distinct orbital-scale series of CaCO3 and opal variations are apparently parallel between the two cores, which are mainly controlled by an eccentricity with an approximately 100-kyr periodicity. However, the patterns of biogenic CaCO3 and opal deposition between the interglacial and glacial periods are different at the two cores.