Causes of compressional- wave anisotropy in calcareous sediments from the Rio Grande Rise ( DSDP, Leg 72).

Abstract

Forty indurated sediment samples from Site 516 were studied to determine the cause of acoustic anisotropy in carbonate-bearing deep-sea sediments. The major findings are: 1) Carbonate-bearing deep-sea sediments may be regarded as transversely isotropic media with symmetry axes normal to bedding. 2) Calcite c-axes are weakly concentrated in a direction perpendicular to bedding, but the preferred orientation of calcite does not contribute significantly to velocity anisotropy. 3) The properties of bedded and unbedded samples are distinctly different. Bedding must regarded as the principal cause of acoustic anisotropy in calcareous, deep-sea sediments. -from Authors