A Comparison of Characteristics of Infilling Sediments in Mud-Capped Dredge Pits on the Louisiana Continental Shelf

Due to high sedimentation rate of ~1 m/year, mud-capped dredge pits (MCDP) are often considered as natural labs to study detailed sedimentary processes, slope stability, and the impacts of dredging activities on marine environments. Although many studies have been performed on the Louisiana shelf, there is a lack of high spatial resolution research covering the eastern, central, and western regions of Louisiana shelf to comprehensively investigate sediment infilling in multiple MCDPs. Eighteen vibracores were collected from Peveto Channel dredge pit (PC), Raccoon Island dredge pit (RI), and Sandy Point dredge pit (SP) and more than 1300 samples were analyzed, to study the spatial variation of surficial sediment through statistical analysis. Our results indicate that the inner Louisiana continental shelf is silt dominated, sediment inside the pit could have bigger or smaller grain size compared to the sediment outside the pit, and the skewness is the most influential explanatory variable based on the absolute value of the standardized coefficients in RI and SP while the skewness is the most influential explanatory variable in PC. Our analysis shows that two principal components are confirmed and account for more than 95% of the total grain size variance.