Physical Properties of Calcareous Sediments from the Southwest Pacific

Abstract

The extensive hydraulic piston coring activity on Leg 90 provided hundreds of meters of good quality sediment from which to conduct a comprehensive physical properties examination of nannofossil ooze and chalk. Most sites exhibit a well-defined transitional zone between the soft ooze and the indurated chalk, and a clear correlation is established between the onset of this region and sharp increases in sediment shear strength. Distinct increases in the values of compressional velocity and thermal conductivity across the ooze-to-chalk transformation are less evident. In a few instances, the porosity-versus-depth profiles depict zones where sediment porosity remains relatively constant across substantial depth intervals. Porosity is seemingly unaffected by large increases in overburden pressure, and no significant compaction occurs across several hundred meters of the sediment column. This behavior is attributed to a combination of several environmental factors. It is postulated that remarkably high sedimentation rates, a high diagenetic potential, and, perhaps, an appropriate grain size distribution all have had some relative influence in promoting sediment rigidity and retarding compaction.

Coupled productivity and carbon isotope records in the southwest Pacific Ocean during the late Miocene–early Pliocene biogenic bloom

“…Porosity data for our samples were extrapolated from the nearest sample analyzed for physical properties (Morin, 1986). The particle density is approximately 2.7 g/cm 3 , given that the sediment is almost entirely carbonate.…”

U.S. Geological Survey research in radioactive waste disposal - Fiscal years 1983, 1984, and 1985

“…A cooperative study of the Brule aquifer in the Olegocine Brule Formation (Barrash, W., and Morin, R. H., 1985) was carried out with the University of Nebraska. The results brought together data from well logs, core analyses, and pumping-test data.…”