Open AccessThe Holocene preservation history of equatorial Pacific sediments
Author(s) -
Oxburgh Rachel
Publication year - 1998
Publication title -
paleoceanography
Language(s) - English
Resource type - Journals
eISSN - 1944-9186
pISSN - 0883-8305
DOI - 10.1029/97pa02607
Subject(s) - calcite , carbonate compensation depth , geology , holocene , sediment , glacial period , dissolution , oceanography , radiocarbon dating , weathering , deposition (geology) , geochemistry , geomorphology , paleontology , chemistry
A model of the sediment mixed layer is used to quantify the glacial‐Holocene changes in calcite preservation (productivity minus dissolution) at water depths that span the transition between lysocline and calcite compensation depth in the equatorial Pacific. The mean preservation fluxes required by the model to account for the observed changes in sediment composition indicate, in most cases, that calcite dissolution exceeds supply and that there has been net removal of calcite from surface sediments over the Holocene. The sediment mixed layer is therefore not at steady state with respect to CaCO 3 fluxes. The model is also used to show that an observed increase in the radiocarbon age of the core top sediments with increasing extent of dissolution cannot be explained by chemical erosion of underlying glacial material. Dissolution taking place at or just below the sediment‐water interface is the probable cause of this phenomenon.