Shear strength and stability of continental slope deposits, western Gulf of Mexico

Sediments from the continental slope in the western Gulf of Mexico were tested to determine the shear strength, stability, and consolidation characteristics. Although the topography of parts of the continental slope has been attributed to local slumping of unconsolidated and unstable marine sediments, no evidence was found to indicate instability of the sediments in the present environment. Continental slope sediments tested exhibit apparent overconsolidation and possess relatively high values of shear strength. This stability is assumed to be the result of low deposition rates and incipient cementation of mineral grains. Carbonate content and volcanic debris may also affect shear strength. Paleontological evidence indicates that some of the sediments in the Campeche canyon were deposited as the result of slumping and turbidity currents during the Pleistocene. The test results show, however, that these sediments are also stable in the present environment.