APPLICATION OF SEDIMENT END-MEMBER ANALYSIS FOR UNDERSTANDING SEDIMENT FLUXES, NORTHERN CHANDELEUR ISLANDS, LOUISIANA

摘要

We analyzed grain-size distributions (GSDs) from a time-series of sediment samples to evaluate sediment transport following anthropogenic sand-berm emplacement at the northern Chandeleur Islands, Louisiana. End-member analysis (EMA) was applied to compare the end-member (EM) GSD of a known sediment source to GSDs from surrounding environments and characterize the physical redistribution of source sediment over time. Although we successfully modeled a proxy borrow-source EM using pre-emplacement (2007-2008) datasets, this EM is not easily distinguishable from the modeled emergent-island EM, possibly because the baseline dataset did not provide the necessary sample distribution to distinguish the range of depositional environments. Comparison of post-emplacement (2012) samples from the berm and natural island with the proxy borrow-source EM suggests that this application of EMA can be a valuable tool for understanding sediment redistribution subsequent to restoration efforts, especially if the GSDs of the emplaced and naturally-occurring sediments are dissimilar and adequately sampled.