Multi-proxy paleotempestological reconstruction from Jobos Bay, Puerto Rico: Applying the sedimentological imprint of Hurricane Maria (2017) as a modern analog

Keywords: paleoenvironment, sediment, hurricane, flood, storm surge, loss-on-ignition, XRF
Abstract Type: Paper Abstract

Abstract

Hurricane Maria hit Puerto Rico on September 20, 2017 as a powerful category 4 storm, responsible for significant loss of life along with serious economic and environmental damages. Maria caused severe storm surge in coastal areas, in addition to heavy precipitation throughout the island which led to immense and widespread fluvial flooding. Due to these combined impacts, the landfall of Maria offers a unique opportunity to capture and analyze its sediment deposition with multiple proxies to better determine the mechanism(s) (i.e., marine and/or terrestrial) responsible for older, paleohurricane deposits. In July 2021, 25 sediment cores and 12 surface samples were extracted from four coastal sites and one interior site in Puerto Rico. Here, we present preliminary results from Jobos Bay, located 30 km southwest from Maria’s track. Core JOB 4 (209 cm long) was extracted with a peat borer, and subjected to high-resolution loss-on-ignition and x-ray fluorescence (XRF) analysis. JOB 4 is comprised mostly of peat, with four embedded sand layers (45-51, 57-71, 90, 115-122 cm) consisting of low organic content (10-40%) and elevated carbonate (20-30%) and silicate (30-60%) concentrations. High concentrations of Cl in these sand layers suggests that they were likely deposited via storm surge processes. These four layers are likely hurricane-derived, with two of them dated to 1583 and 3510 cal yr BP. A thin clay layer at three cm depth with elevated Ti concentration may have been deposited by Maria-induced slopewash, but future work focused on improving our chronology will confirm this.