Acoustic and physical property correlation of marine sediments from the Texas-Louisiana continental shelf

Analysis of 212 samples from 23 gravity cores obtained on the Texas-Louisiana continental shelf shows that nearshore sediments in the southwestern part of the study area, closest to Corpus Christi, are a mixture of sand-silt-clay and silty clay (using the Shepard, 1954, classification), with clay percentages increasing farther from shore. Deeper-water clays have the lowest sound velocities (1413-1519 m/s), lowest dry densities (2.61-2.65 g/cm/sup 3/), highest porosities (70-80%), and slightly higher calcium carbonate contents (0-5% to 5-10%). Sediments in the northeastern part of the study area, off east Texas and southwest Louisiana, are dominantly composed of sand-silt-clay and clayey sand. These cores have the highest sound velocities (1526-1704 m/s), highest dry densities (2.66-2.74 g/cm/sup 3/), lowest porosities (36-67%), and generally lower calcium carbonate content (0-5%) than cores from the southwestern shelf. A linear correlation exists between acoustic and certain physical properties: an increase in mean grain size (smaller phi numbers), decreased clay content, and lower porosity produces an increase in sound velocity. Sand content and bulk grain density increase as sound velocity increases. No correlation was found between calcium carbonate content and sound velocity.