SGER: Long-term hurricane landfall records derived from marine microfossils in freshwater lake bed sediments

University Of North Texas, Denton TX

Investigators

Abstract

This SGER proposal is a pilot study designed to test a novel new approach in the field of paleotempestology. The objective of the study is to test the hypothesis that hurricane storm surges are recorded by sediments rich in marine microfossils (foraminifera) in freshwater ponds and lakes several km inland from the coast. To date, most paleotempestology studies have been based on finding and dating sand layers transported by storm surges. This approach, however, has been limited by the relatively low number of suitable sites ? lakes and marshes within a few hundred meters of sandy shorelines ? and many areas, including the entire coastline of Texas, remain unstudied. If this new approach is proved viable, it has the potential to provide long-term records of hurricane strikes and to expand paleotempestology studies into many new areas that were previously thought to lack sites suitable for capturing a hurricane signal. The study will be conducted at the McFaddin Wildlife Refuge in southeast Texas. The refuge has numerous natural freshwater ponds and lakes lying within a few km of the coast that are known to have been flooded by historical hurricane storm surges. Sediment cores will be obtained from several pond and lake beds and will be examined for foraminifera-rich layers. A chronology for identified hurricane deposits will be established by a combination of cesium-137 and radiocarbon dating techniques. Intellectual merit This project will build on a study by the PI of storm surge sediments deposited by Hurricane Rita (2005), including new findings on the microfossil content of the deposits. If the hypothesis tested in this study proves viable, it will represent a new approach in the field of paleotempestology that can be applied at many previously unstudied sites along the Atlantic and Gulf coasts. This will increase the number and areal coverage of long-term hurricane records, which will be of considerable value in fields such as hurricane risk assessment, the role of hurricanes in coastal geomorphological evolution and studies of the relationship between hurricane activity cycles and climate change. Broader Impacts This project has important societal and educational benefits. Societal benefits will include improved assessments of the recurrence interval of hurricane strikes and associated hurricane risk. The approach developed in this project could result in improved spatial resolution of hurricane risk along the Atlantic and Gulf coasts and a better understanding of the effects of climate change on hurricane activity. An undergraduate student from an underrepresented group will participate in the field and laboratory work and will be encouraged to contribute to conference presentations and publications. The results of this project will be broadly disseminated to enhance scientific and technical understanding in a variety of ways, reaching scientific researchers, policy-makers and the public-at-large. It is anticipated that this project will result in several conference presentations and peer-reviewed journal articles.