A 7000-year Sedimentary Record of Paleohurricane Activity from Northern Nicaragua

Liu, K.B. and McCloskey, T.A., 2024. A 7000-year sedimentary record of paleohurricane activity from northern Nicaragua. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 976-980. Charlotte (North Carolina), ISSN 0749-0208. We present a new paleotempestological proxy record from a backbarrier marsh near Puerto Isabel (PI) in northern-Nicaragua that spans the last 7000 years. Two parallel cores contain 2.7 to 4.0 m of muddy peat overlying gray clay. Multiple clastic layers occurring in the peat section represent storm deposits that record a history of intense hurricane strikes. These clastic layers were probably deposited primarily by floodwaters from the Prinzapolka River due to heavy rainfall associated with hurricane landfalls, with some contribution from seawater intrusion due to storm surges. Radiocarbon dating of clastic layers indicates that hurricane strike events were more frequent during 850-0 and 3700-2200 cal yr BP, while relatively few events occurred during the periods 7000-3700 cal yr BP and 2200-850 cal yr BP. This pattern of paleohurricane activity is generally consistent with that reconstructed from the Falso Bluff Marsh (FBM) site in southern Nicaragua, but clearly anti-phase with that from Puerto Rico. Our proxy records from Nicaragua support the notion that paleohurricane activity regimes are not synchronous across the Atlantic basin. Periods of high hurricane activity in Nicaragua corresponded with times when the ITCZ shifted to the south, suggesting that ITCZ movements played a major role in steering Caribbean hurricane tracks to the south during the Holocene.