A multi-proxy approach to characterizing hurricane-derived deposits in coastal and inland environments

Florida Agricultural And Mechanical University, Tallahassee FL

Investigators

Abstract

This project uses a multi-proxy approach to characterizing hurricane-derived deposits in coastal and inland environments impacted, respectively, by hurricane-related storm surge and river flooding processes. Hurricanes can impact a region by causing storm surge flooding related deposition along the coast as well as river flooding in inland areas due to heavy precipitation. Description and analysis of hurricane-induced present-day coastal and inland sediment deposits are vital for deciphering the origins of storm deposits and understanding the relative contribution of a variety of sedimentary processes in different environmental settings. By using multiple proxies, this study provides accurate descriptions of the storm deposits generated by a recent intense hurricane in both the coastal and inland environments. Results from this study provide critical information for identifying ancient storm deposits in the geological record, which advances the study of past hurricane activity in the context of environmental variability at timescales of centuries and millennia. From this analysis of hurricane impacts in deeper time societal benefits are derived because long-term records of hurricane activity are vital for accurate risk assessment for present and future coastal communities. The project also provides educational and professional development opportunities for students and faculty at a minority-serving institution. The objective of this project is to assess key coastal and terrestrial environments along the path of a recent hurricane, Hurricane Maria in 2017, and to identify and characterize its coastal storm surge and inland river flood deposits. This research identifies prominent hurricane-induced sediment deposition in coastal and interior environments that sheds light on the severity and geographical variation of storm impacts in different geomorphological settings, thus offering a modern analog that assists the search for the evidence of ancient hurricanes in the geological record. Short cores to be collected from a few coastal lagoons and inland wetlands will be analyzed chronologically (using Pb-210 and Cs-137 radioisotopes), sedimentologically (using loss-on-ignition and grain-size analyses), geochemically (using X-ray fluorescence analysis), and micropaleontologically (using foraminifera and palynological analyses) to identify and characterize the Hurricane Maria deposits. Chemical elemental ratios (such as Cl/Br and Ca/Fe) and biological proxies (especially palynomorphs and foraminifera) will be used to differentiate the effects of freshwater flooding versus saltwater intrusion that represent two different types of environmental impacts. Although this research project will focus on Hurricane Maria related deposits in Puerto Rico, the research will provide new insights and approaches for identifying the coastal and inland environmental impacts of other intense storms in the continental U.S., which helps society better prepare for these extreme events in the future. 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.