Geotechnical Properties of Marine Sediments from Gulf of Mexico: ABSTRACT

Abstract

Sediment cores collected from three areas of the Gulf of Mexico--the Louisiana continental shelf, the Mexican shelf-slope, and the abyssal plain--were examined to determine their geotechnical properties. As these three areas have diverse sedimentation rates ranging from rapid in proximity to the Mississippi delta to very slow on the abyssal plain, the cores were studied with the expectation that a correlation would be evident between rate of deposition and the following properties: shear strength, wet density, water content, grain-size distribution, and porosity. The cores examined from the Louisiana and Mexican shelves and the abyssal plain exhibited similar characteristics, with shear strength in the upper 10 feet of the cores averaging about 90 lbs./sq. ft. The shear-strength values of the cores taken on the Mexican slope average much higher (170 lbs./sq. ft.), with some zones having a shear strength as high as 800 lbs./sq. ft. Such a high shear strength is caused by authigenic cementation and the presence of volcanic shards. Statistically speaking, the remaining parameters measured showed less correlation between zones than did shear strength. It is assumed from this study that, although the shelf and abyssal zones are being subjected to different sedimentation rates, the processes of sedimentation are such that sediments on the Louisiana and Mexican shelves and the abyssal plain are underconsolidated as opposed to the slope sediments, which are in a normal to overconsolidated state. End_of_Article - Last_Page 606------------