Estimation of biogenic silica contents in marine sediments using seismic and well log data: Sediment Drift 7, Antarctica

Petrophysical parameters (bulk density, porosity, P-wave velocity) were used to predict the biogenic silica content along a seismic profile that ties two well sites (1095 and 1096) drilled by Ocean Drilling Program (ODP) Leg 178 on sediment drifts on the Pacific continental margin of the Antarctic Peninsula. The biogenic silica contents along the seismic profile were estimated on the basis of three hypotheses about the petrophysical parameter distributions in the two boreholes and statistical relationships between biogenic silica and other petrophysical parameters, which were established on various sediment layers within each borehole. Our study demonstrates the possibility to predict in a reliable way the distribution of biogenic silica in the seabed sediments if seismic data processed with amplitude preservation are used and statistical relations are considered. We conclude that the statistical extrapolation of biogenic silica content along seismic profiles tied to borehole data is an efficient tool to quantify the amounts of opal undergoing crystalline transformation.