Sedflume Analysis of the Resuspension of Deep Gulf of Mexico Sediments

Following the release of ~4.9 million barrels of oil into the Gulf of Mexico from the Macando wellhead, a vast area of the seafloor contained recently deposited marine sediments contaminated by the oil spill. The initial deposition of these contaminated marine sediments was likely not the end of the journey for the particles. Events of increased current speed in the deep ocean setting can result in recently deposited sediments to resuspend and be moved laterally with the current flow. Understanding the process of resuspension and transport of recently deposited sediments provides information needed to estimate the extent of how much material might have been moved by the currents. Erosion experiments are actively being performed with a Sedflume (McNeil, 1994) to analyze sediment cores from 27 locations collected in the southeastern Gulf of Mexico. Using flow modeling of the Gulf of Mexico, core sites were chosen to be in areas where erosion or deposition is thought to be the dominant process of that coring location. Data collected from these flume experiments will provide the difference in the critical velocity needed to begin erosion in these different sedimentation environments. Using image data, size-specific grain size distribution analyses of the recently eroded sediments will be provided, with expectations of Hjulström-like results. With larger particles being eroded first, this could support the idea that larger, recently deposited marine snow particles can be more easily transported than smaller surrounding particles. These results will offer a better understanding of the remobilization and transport of sediments into the deep Gulf of Mexico.