Abstract:
The dry bulk density (
DBD) of marine sediment is an important parameter to calculate the mass accumulation rate and estimate the sediment flux in geological history. Due to sparse sampling interval, data of
DBD in many borehole sediments are often poor in resolution or even unavailable, which restricts subsequent studies. Previous studies have found that the
DBD of deep-sea sediments can be estimated via the content of CaCO
3 in the sediments. However, whether this method is feasible for the South China Sea (SCS) sediments remains unknown. In this study, we collected and analyzed data of
DBD, CaCO
3 content (CaCO
3%), and burial depth of downcore sediment samples from 17 sites in four ODP/IODP expeditions of Legs 184, 349, 367, and 368 in the SCS. Results showed that the burial depth is an important factor affecting DBD in the southern SCS where currents are less dynamic as represented by the ODP1143 site, showing significant
DBD-CaCO
3% relationship; while in the northern and central SCS, relationship between
DBD and CaCO3% is poor due probably to dynamic currents and multiple non-CaCO
3 inputs, which leads to the unstable sedimentary environments. Using the burial depth and CaCO
3% of the ODP1143 site as variables, an empirical binary polynomial fitting equation for
DBD was established, which may be applicable for the
DBD estimation for the southern SCS where the sedimentary environment is similar to that of the ODP 1143 site.