Summary of Physical Properties—Leg 32

Abstract

POROSITY AND DENSITY The GRAPE and syringe measurements of porosity and density were confined almost exclusively to the un-lithified sediments. These soft-stiff sediments are typically moderately to intensely disturbed during drilling, which suggests that their porosity is somewhat greater and wet bulk density somewhat less than the in situ values. With the exception of Site 304, where the grain density of the pelagic clay is significantly higher than that of the siliceous oozes, the syringe data show that the variations in wet bulk density of the sediments at each site are due largely to changes in porosity. The porosity was therefore measured by applying the average grain density as determined by the syringe data at each site to the GRAPE wet bulk density measurements. The porosity of the near-surface sediments is least in the calcareous oozes, 65%-70%; greatest in the siliceous oozes, 85%; and intermediate in pelagic clay, 80% (Table 'Present address: