Collaborative Research: a multi-proxy approach to discrimination of marine and terrestrial sediments in coastal wetlands

Computer modeling results and empirical data analyses have indicated that anthropogenic global warming has caused hurricanes to become stronger, wetter, and slower-moving. As a result, coastal communities are facing increasing risks from compound flooding events caused by a combination of stronger hurricane winds, higher storm surges, heavier precipitation, and more severe flooding from rivers. For coastal risk managers, it is critical to have an improved understanding of the relative contribution between marine and terrestrial sources in these compound flooding events. This study will use an innovative approach to discriminate between marine and terrestrial deposits in sediment cores collected from multiple wetland sites impacted by recent hurricanes. Identifying sediment provenance will also elucidate the relative contributions of marine and terrestrial inputs to wetlands aggradation and provide valuable insights on wetland sustainability for coastal management agencies. This study will employ a multi-proxy approach to the discrimination of saltwater and freshwater sediment beds within sediment cores collected from a variety of coastal wetland environments. Spearheading the analysis will be the use of X-Ray Fluorescence (XRF) to discriminate between marine and terrestrial sediments based on their chemical elemental composition. Pilot studies of the XRF technique, aimed at establishing elemental signatures of storm surge and fluvial sediment beds resulting from Hurricane Harvey (2017), show promise, but additional work to refine the technique and extend it to other environmental settings is warranted. Additional analytical techniques to be employed in the study include textural, loss-on-ignition, palynological, and foraminiferal analyses, and radio-isotopic dating for chronological control. This project is jointly funded by the Geomorphology and Land Use Dynamics (GLD) Program and the Established Program to Stimulate Competitive Research (EPSCoR). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.