Biogenic sediments on the Eauripik Rise of the western equatorial Pacific during the late Pleistocene.

Abstract

It has been suggested that late Quaternary variability in atmospheric CO2 concentrations may have resulted from variations in the nature of biogenic sedimentation. In this paper we present 262 kyr time series for the mass accumulation rates of organic carbon (MAROC), carbonate (MARCarbonate), and biogenic opal (MARopal) of the Eauripik Rise, the western equatorial Pacific. The MAROC record exhibits a general trend of higher values during glaciation time; Stage 2, Stage 3, Stage 4, Stage 6 and late Stage 8 except middle Stage 5. A weak correlation between MAROC and MARopal as well as MARCarbonate is attributed to the oligotrophic character of the western Pacific in the Eauripik Rise area. Spectral analysis of organic carbon contents displays eccentricity, obliquity and precession-related peaks. The presence of 23-kyr periodicity indicates a possible link between organic carbon burial and trade winds associated with insolation.