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Organic geochemical proxies (OGPs) preserved in coastal lake sediments have recently been used to reconstruct millennia-long hurricane records. Although OGPs (δ13C, δ15N and C/N) appear to be a more sensitive indicator of past storm events than traditional proxies used in paleotempestology, the method has not been tested in many lakes with modern data. In this study, we measured the δ13C, δ15N and C/N values of particulate organic matter (POM), along with the salinities and stable isotopic compositions of water (δ18O and δD), in two coastal lakes on seasonal or much shorter time scales throughout a 3-year period. This work was intended to develop a better understanding of the dynamics of OGPs in these lakes. The time-series data not only show that geochemical properties of these lakes varied seasonally, reflecting variations in lake biological and environmental conditions, but displayed unique variation patterns in response to storms that caused either seawater flooding or freshwater flooding of the lakes. The data show that seawater flooding led to higher δ13C and δ15N values, with either lower or no change in the C/N ratios of the POM, generally consistent with a previously proposed conceptual model for detecting seawater flooding events. The data also show that freshwater flooding reduces δ15N and increases the C/N values of POM, in addition to lowering the salinity, δ18O and δD of lake water. These time-series modern data demonstrate the feasibility of detecting past storm events that were large enough to cause either seawater or freshwater flooding by examining variation patterns of multiple OGPs in coastal lake sediments. Applying this understanding to a sediment core from one of the study lakes (Mullet Pond, Florida), we reconstructed a centuries-long record of storms based on the variation patterns in OGPs together with 210Pb ages. The OGP-based storm record suggests that 30 flooding events, including 15 seawater flooding and 15 freshwater flooding incidents, occurred over the last 165 years. Almost all of these flooding events can be matched (within the dating uncertainty) to the historic hurricanes that are known to have passed within 150 km of the study site. This further confirms that OGPs preserved in sediments in coastal lakes of Florida or similar regions may be used as reliable recorders of past storm activity.

For more than a century, tree-ring research has identified relationships between climatic and ecological conditions and tree growth to describe past environments and constrain future ecosystem vulnerabilities. Tree-ring records are frequently used as environmental proxies that extend knowledge of past climate and ecology on millennial scales. Many of the most pressing global change questions facing North America concern the rate of climate change and vulnerability of ecosystems and society along the coast. The opportunities and applications in dendrochronology continue to grow with advancing methodologies, faster computational ability, and the cost-reduction of many chemical and anatomical analyses. Here, we propose that many pressing global change questions that affect coastal communities can be addressed using dendrochronological techniques. We review coastal tree-ring studies that demonstrate the utility and potential for future tree-ring studies in the northeastern, southeastern, northwestern, and southwestern North American coasts. Additionally, we show that tree-ring chronologies along the coast give insight into local and regional climate phenomena that are distinct from nearby, inland tree-ring chronologies of the same species. Lastly, we identify opportunities for coastal dendrochronology and encourage the collection of more tree-ring records that are directly impacted by coastal phenomena.

Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

Reconstruction of the generation, development, and evolution of modern storms through paleotempestology is used to understand the regularity of storm activity and the relationship between storm activity and global climate change. Existing paleotempestology research in China is concentrated mainly on the low latitude sediments deposited since the Holocene (about 7000 a). In this study, we examine the storm deposits in the eolian sediments of the Bohai Sea coastal zone at middle latitudes, choosing the Miaodao stratigraphic section (MDS) as the target area. This area is located in the Bohai Sea strait and shows evidence of storms since the last interglacial period using an analysis of the grain size parameter, element ratios, and marine micropaleontology foraminifera fossils in the sediment during the last 130 ka that can be used in our paleotempestology research. The results include three main findings: (1) the marine micropaleontology foraminifer fossils appear in the eolian sediment of the MDS and, in combination with grain size parameter and element ratios of the sediments, serve as evidence of the paleotempestology record on the Bohai Sea coastal zone; (2) planktonic foraminifera fossils appear in the MDS, indicating that the Yellow Sea warm current affected the Bohai Sea during the last interglacial period; and (3) storm activity in the marine isotope stage (MIS) 5a has been recorded in the MDS 15 times. The findings of this study expand the paleotempestology record from 7000 a to 90 ka and serve as a reference for research for middle latitude storm activity.

Coastal geologic records allow for the assessment of long-term patterns of tropical cyclone variability. However, the accuracy of geologic reconstructions of tropical cyclones is limited by the lack of modern analogues. We describe the microfossil (foraminifera and testate amoebae) assemblages contained within overwash sediments deposited by Typhoon Haiyan when it made landfall on the islands of Leyte and Samar in the Philippines on 7 November 2013 as a Category 5 super typhoon. The overwash sediments were transported up to 1.7 km inland at four study sites. The sediments consisted of light brown medium sand in a layer

Washover sedimentation resulting from modern typhoon strikes on the Gulf of Thailand coast forms anomalous sand layers in low-energy coastal environments including marshes, ponds and swales. The primary diagnostic for recognizing prehistoric typhoon-deposited sand layers in the geologic record are sharp upper and lower contacts between coarser-grained transported sand layers and finer-grained in-situ sediments. In this first paleotempestology study in Thailand, cores from two low-energy settings on the Gulf of Thailand coast – a coastal marsh near Cha-am and beach ridge plain swales near Kui Buri – reveal geologic evidence of up to 19 typhoon strikes within the last 8000 years. The sand layers have sharp upper and lower contacts with enclosing finer sediments. Some sand layers also contain other evidence of a sudden powerful landward-directed surge of ocean water, including gravel-sized clasts, offshore foraminifera, abundant shell fragments, plant debris and mud rip-up clasts. Sand layers record eleven typhoon strikes at Cha-am, ranging in age from AD 1952 to 7575 cal. yr. BP, and eight typhoon strikes at Kui Buri, ranging in age from 4075 to 7740 cal. yr. BP. Bayesian age–depth models, derived from eight AMS radiocarbon dates, suggest that the frequency of typhoon strikes was 2–5 times greater from 3900 to 7800 cal. yr. BP compared to 0–3900 cal. yr. BP. Possible explanations for this variability in the typhoon record are that typhoons were more frequent and/or more intense in Southeast Asia in the mid-Holocene because of climatic changes associated with the Mid-Holocene Warm Period or that the record reflects site sensitivity changes resulting from a mid-Holocene sea-level highstand. The preliminary finding of a possible link between warmer conditions and a greater frequency of intense typhoon strikes could have important societal implications, given possible consequences of ongoing global warming.

Recent research has proposed that human-induced sea surface temperature (SST) warming has led to an increase in the intensity of hurricanes over the past 30 years. However, this notion has been challenged on the basis that the instrumental record is too short and unreliable to reveal long-term trends in hurricane activity. This study addresses this limitation by investigating hurricane-induced overwash deposits (paleotempestites) behind a barrier island in Naples, FL, USA. Paleotempestologic proxies including grain size, percent calcium carbonate, and fossil shells species were used to distinguish overwash events in two sediment cores spanning the last one thousand years. Two prominent paleotempestites were observed in the top 20 cm of both cores: the first identified as Hurricane Donna in 1960 whereas an older paleotempestite (1900–1930) could represent one of three documented storms in the early 1900s. An active period of hurricane overwash from 1000 to 500 yrs. BP and an inactive period from 500 to 150 yrs. BP correlate with reconstructed SSTs from the Main Development Region (MDR) of the North Atlantic Ocean. We observe an increased number of paleotempestites when MDR SSTs are warmer, coinciding with the Medieval Warm Period, and very few paleotempestites when MDR SSTs are cooler, coinciding with the Little Ice Age. Results from this initial Southwest Florida study indicate that MDR SSTs have been a key long-term climate driver of intense Southwest Florida hurricane strikes.

Deciphering how the climate system has controlled North Atlantic tropical cyclone activity through the Holocene will require a larger observational network of prehistoric hurricane activity. Problematically, the tropical North Atlantic is dominated by carbonate landscapes that typically preserve poorer quality coastal sediment records in comparison to their temperate-region counterparts (e.g., sedimentation continuity and rate). Coastal karst basins (CKBs), such as sinkholes, blueholes, and underwater caves, are widely distributed on carbonate platforms and contain overlooked sedimentary records. Here we present a millennium of hurricane deposits on the Little Bahama Bank archived in a 165 cm core that was extracted from 69 m below sea level in a bluehole on Great Abaco Island, The Bahamas. The coarse-grained overwash deposits associated with both hurricanes Jeanne (2004) and Floyd (1999) were identified using radioisotopes (137Cs, 14C, 210Pb), and indicate that the bluehole is sensitive to hurricane-induced sedimentation. Over the last millennium, the Little Bahama Bank experienced heightened hurricane activity from 1350 to 1650 AD. The simplest explanation for this active interval is that favorable climate conditions (El Nino, West African Monsoon, and sea surface temperatures) encouraged North Atlantic hurricane activity at that time. However, asynchronous hurricane activity at similar latitudes in the North Atlantic and Gulf of Mexico suggest that regional oceanography has modulated or amplified regional hurricane activity over the last millennium.

We lack an understanding of the geographic and temporal controls on South Pacific cyclone activity. Overwash records from backbarrier salt marshes and coastal ponds have been used to reconstruct tropical cyclone strikes in the North Atlantic basin. However, these specific backbarrier environments are scarce in the South Pacific, with cyclone records limited primarily to the period of modern observation. This instrumental record suggests a correlation with the El Nino–Southern Oscillation (ENSO), but longer records are necessary to test this relationship over geologic timescales and explore other potential climate drivers of tropical cyclone variability. Deep lagoons behind coral reefs are widespread in the Pacific and provide an alternative setting for developing long-term sedimentary reconstructions of tropical cyclone occurrence. Coarse-grained event deposits within the sediments of a back-reef lagoon surrounding Tahaa reveal a 5000-year record of cyclone occurrences. Timing of recent high-energy deposits matches well with observed tropical cyclone strikes and indicates coarse deposits are storm derived. Longer records show tropical cyclone activity was higher from 5000 to 3800 and 2900 to 500 yrs BP. Comparison to records from the North Pacific (out-of-phase) and North Atlantic (in phase) suggests a coordinated pattern of storm activity across tropical cyclone basins over the mid-late Holocene. The changes in tropical cyclone activity we observe in the South Pacific and across other basins may be related to ENSO as well as precession driven changes in ocean-atmosphere thermal gradients.

Late Holocene paleoclimate records from coastal regions are important for understanding long-term variability of hurricane activity. Here we present a nearly 4000-year record of severe storm landfalls and environmental changes based on organic geochemical proxies (OGPs) preserved in sediment cores from two coastal lakes in northwest Florida. Our analysis shows that there are significant variations in δ13C, δ15N, C%, N% and C/N with depth, reflecting changes in lake environment, which in turn affected the processes delivering water and sediment to the lake as well as biological productivity within the lake. Isotopic signatures of modern organic materials in the lakes and their surrounding areas show that the major sources of sedimentary organic matters in the lakes are aquatic and terrestrial C3 vegetation. C4 grasses do not contribute significantly to the sedimentary organic matters in the lake, although they can be found in the mostly forested watershed. Thus, the positive C and N isotopic shifts, concurrent with negative shifts in C/N ratios, most likely indicate shifts to a marine-like environment in coastal lakes following the influx of marine water and nutrients and marine biota associated with major storm events. Some of these isotopic shifts observed in the sediment cores correspond to visible sand layers presumably representing overwash deposits associated with severe storm events. Radiocarbon dating of bulk sediment organic matters, wood fragments and shells indicates that the sediment in these cores was deposited over the last 3000–4000 years. Based on our age model and OGP interpretation, Eastern Lake data suggest that the recurrence interval of severe storms (i.e., large enough to cause seawater flooding of the lakes) is approximately 84 years over the last 2900 years, whereas Western lake data suggest an average recurrence interval of 86 years in the past 3900 years.

This study tests a novel approach to paleotempestology, substituting the lateral time-depth of a prograding beach ridge plain for the vertical time-depth of an aggrading coastal lake, pond, lagoon, swamp or marsh. Trenching and coring of a beach ridge plain in southwestern Louisiana revealed six sand beds and one shell bed, interpreted as hurricane washover deposits. The sand beds are readily distinguished from enclosing marsh sediments by their higher sand content, lower organic content and contrasting microfossil assemblages. Based on the modern analogs of hurricanes Audrey (1957), Rita (2005) and Ike (2008), and consideration of nearby landfalling hurricanes in the historical record, it was determined that the storm intensity threshold of the study site is equivalent to a Category 3 hurricane. There is a wide variation in hurricane strike frequency between this site and other sites bordering the Gulf of Mexico. This variation results from differences in site sensitivity and the nature of geologic or geochemical proxies used to derive hurricane strike records. The approach demonstrated by this study could have applicability at other sites around the world where beach ridge plains are subject to tropical cyclone strikes.

article i nfo A 4500-year record of hurricane-induced storm surges is developed from sediment cores collected from a coastal sinkhole near Apalachee Bay, Florida. Recent deposition of sand layers in the upper sediments of the pond was found to be contemporaneous with significant, historic storm surges at the site modeled using SLOSH and the Best Track, post-1851 A.D. dataset. Using the historic portion of the record for calibration, paleohurricane deposits were identified by sand content and dated using radiocarbon-based age models. Marine-indicative foraminifera, some originating at least 5 km offshore, were present in several modern and ancient storm deposits. The presence and long-term preservation of offshore foraminifera suggest that this site and others like it may yield promising microfossil-based paleohurricane reconstructions in the future. Due to the sub-decadal (~7 years) resolution of the record and the site's high susceptibility to hurricane-generated storm surges, the average, local frequency of recorded events, approximately 3.9 storms per century, is greater than that of previously published paleohurricane records from the region. The high incidence of recorded events permitted a time series of local hurricane frequency during the last five millennia to be constructed. Variability in the frequency of the largest storm layers was found to be greater than what would likely occur by chance alone, with intervals of both anomalously high and low storm frequency identified. However, the rate at which smaller layers were deposited was relatively constant over the last five millennia. This may suggest that significant variability in hurricane frequency has occurred only in the highest magnitude events. The frequency of high magnitude events peaked near 6 storms per century between 2800 and 2300 years ago. High magnitude events were relatively rare with about 0-3 storms per century occurring between 1900 and 1600 years ago and between 400 and 150 years ago. A marked decline in the number of large storm deposits, which began around 600 years ago, has persisted through present with below average frequency over the last 150 years when compared to the preceding five millennia.

Complimenting modern records of tropical cyclone activity with longer historical and paleoclimatological records would increase our understanding of natural tropical cyclone variability on decadal to centennial time scales. Tropical cyclones produce large amounts of precipitation with significantly lower δ 18 O values than normal precipitation, and hence may be geochemically identifiable as negative δ 18 O anomalies in marine carbonate δ 18 O records. This study investigates the usefulness of coral skeletal δ 18 O as a means of reconstructing past tropical cyclone events. Isotopic modeling of rainfall mixing with seawater shows that detecting an isotopic signal from a tropical cyclone in a coral requires a salinity of ~ 33 psu at the time of coral growth, but this threshold is dependent on the isotopic composition of both fresh and saline end-members. A comparison between coral δ 18 O and historical records of tropical cyclone activity, river discharge, and precipitation from multiple sites in Puerto Rico shows that tropical cyclones are not distinguishable in the coral record from normal rainfall using this approach at these sites.

Sediment cores from two coastal lakes located on the island of Kamikoshiki in southwestern Japan (Lake Namakoike and Lake Kaiike) provide evidence for the response of a backbarrier beach system to episodic coastal inundation over the last 6400 years. Sub-bottom seismic surveys exhibit acoustically laminated, parallel to subparallel seismic reflectors, intermittently truncated by erosional unconformities. Sediment cores collected from targeted depocenters in both lakes contain finely laminated organic mud interbedded with coarse-grained units, with depths of coarse deposits concurrent with prominent seismic reflectors. The timing of the youngest deposit at Kamikoshiki correlates to the most recently documented breach in the barrier during a typhoon in 1951 AD. Assuming that this modern deposit provides an analog for identifying past events, paleo-typhoons may be reconstructed from layers exhibiting an increase in grain-size, a break in fine-scale stratigraphy, and elevated Sr concentrations.

The central coast of Belize has been subject to hurricane strikes throughout recorded history with immense human and material cost to the Belizean people. What remains unknown is the long-term frequency of hurricane strikes and the effects such storms may have had on the ancient Maya civilization. Our sedimentary study of major hurricane strikes over the past 5000 years provides preliminary insights. We calculate that over the past 500 years major hurricanes have struck the Belize coast on average once every decade. One giant hurricane with probably particularly catastrophic consequences struck Belize sometime before AD 1500. A temporal clustering of hurricanes suggests two periods of hyperactivity between ∼4500 and 2500 14 C yr BP, which supports a regional model of latitudinal migration of hurricane strike zones. Our preliminary hurricane data, including the extreme apparent size of the giant event, suggest that prehistoric hurricanes were capable of having exerted significant environmental stress in Maya antiquity.

Studying infrequent phenomena (e.g. hurricanes) and slow processes (e.g. forest regeneration) greatly challenges the ecological techniques of real-time studies. By combining the two relatively new approaches of paleotempestology and fine-resolution palynology, this study provides insight into the impacts of hurricanes and the post-hurricane regeneration of forests. I analyzed a 5-m sediment core from a swamp lagoon on the Caribbean Coast of Nicaragua that covered the entire 8000-yr history of the swamp [Urquhart, G. R., 1997. Disturbance and regeneration of swamp forests in Nicaragua: evidence from Ecology and Paleoecology. Ph.D. Dissertation, The University of Michigan, Ann Arbor, MI, USA]. X-rays revealed a sand layer dating to c. 3300 BP of the type deposited by hurricanes. Pollen analyses showed this sand layer was followed by major changes in vegetation and fires. This pattern is identical to the wake of Hurricane Joan, which struck the area in 1988 and left 90,000 hectares of damaged swamp forest that burned shortly after. After the prehistoric hurricane, forest vegetation did not return until 500 yr later, due to repeated burning. This parallel event of the past illustrates a possible course for modern forest regeneration. As a counterpart to direct ecological analysis, fine-resolution paleoecological study can provide great insight for the study of rare events and slow processes.

The instrumental record of hurricane activity is too short to fully capture the occurrence of the rare but most destructive hurricanes. Therefore, obtaining a record of present and past landfalling hurricanes, and their extent of geological and ecological impacts, is one means to assess future risk, reveal the spatial and temporal variability of hurricane activity and decipher its relationship with global climatic changes. We rapidly dispatched survey teams to collect the readily available, but perishable data of Hurricanes Katrina and Rita storm surge from two salt marshes in Mississippi and one salt marsh in Alabama. In Mississippi, we recorded Hurricane Katrina storm surge heights greater than 7.5 m North American Vertical Datum 88 (NAVD88) with inland extents in excess of 700 m, whereas in Alabama the maximum recorded storm surge was 3.43 m NAVD88. At one salt marsh in Mississippi, we recorded the maximum inland extent and elevation of maximum penetration of Hurricane Rita as 370 m and 3.43 m NAVD88, respectively. We observed a three-dimensional distribution of hurricane-induced storm surge deposits that tapered landward, overlying salt marsh sediment. There was a sharp or erosional boundary between the pre-storm surge and storm surge sedimentary units, which was accompanied by a change in color and lithology. The overlying storm surge sediment unit was coarser than the pre-storm surge unit with a lower organic content. The thickness of the Hurricanes Katrina and Rita storm surge sediments ranged from 9 to 13 cm and approximately 7 cm, respectively. Foraminiferal analyses revealed a virtual absence of tests within the storm surge sediments, whereas abundant agglutinated foraminifera were found in the underlying salt marsh deposits.

The recent increase in typhoon (tropical cyclone) activity has attracted great interest and induced heated debates over whether it is linked to global warming or only a return to an active phase of the well-known multi-decadal variability. Due to the short instrumental record, our knowledge is quite scarce on the complex processes and mechanism of typhoon generation, development, and evolution, especially for the rare but highly destructive super-typhoons. It is therefore very important to extend the time span of typhoon activity records. Paleotempestology, a young science that emerged in the early 1990s, studies past typhoon activity spanning several centuries to millennia before the instrumental era through the use of geological proxies and historical documentary records. This paper presents a brief review and synthesis on the major research advances and findings of paleotempestology with an emphasis on proxy technique development and applications. The methodology has been evolving from single geologic proxy to multi-proxy techniques by integrating microfossils, sedimentary organic elemental ratios, and stable isotopes, together with typical sedimentary textures and structures, for the diagnosis of storm deposits. A newly-developed proxy technique is employing oxygen isotopes preserved in growing laminae of tree rings, cave stalagmites, and reef corals to diagnose typhoon rainwater impacts. Historical documentary records have been systematically compiled and analyzed to reconstruct the history of typhoon activity in some regions. The extracted typhoon-proxy data show that there does not exist a simple linear relationship between typhoon frequency and Holocene climate (temperature) change. Typhoon activity should have a secular and constant linkage with ENSO fluctuations, in that more typhoons and hurricanes make landfalls in China, Central and North America during La Nina years than El Nino years. This finding is consistent with that derived from recent instrumental data. Shifts in positions of subtropical high exert great influence on storm tracks, but their long-term relationship is still not well understood. All these findings are significant in projecting typhoon trends under global warming scenarios. Future developments in paleotempestology should strengthen the following research fields: (1) proxy generation mechanism and preservation potential, (2) inter-validation of different proxy data, (3) recognition of storm and tsunami deposits, (4) evaluation of paleo-typhoon intensity, (5) numerical modeling, and (6) regional to global scale comparison studies.

A stepwise stalagmite sample screening process was applied in order to select a stalagmite as a sensitive recorder of recent tropical cyclone rainfall events near Belize. Field and laboratory criteria were combined in series, to screen out candidate stalagmites whose characteristics indicated lower sensitivity to stormwater infiltration. The approach described here was designed to increase the likelihood that selected stalagmites would increase the signal:noise ratio of the target phenomenon in the resulting proxy records. This four-stage method for sample selection may be an important methodological consideration for researchers attempting to use speleothems for stable isotope paleotempestology. Hallmarks of this approach include: (1) establishing a priori scientific targets, (2) applying sample criteria in the form of contra-indicators, and (3) organizing the sample screening protocol into a series of practical stages. The overall approach to stalagmite selection presented here supports cave conservation, and can be adapted readily by others in support of different scientific goals. It is hoped that other investigators will also publish field and laboratory sample selection schemes, as increased transparency will provide new information invaluable to replication efforts and to advancing the field of speleothem paleo-environmental studies.

Assessing risk from tropical cyclones and predicting the impact of this hazard under a human altered climate is based exclusively upon the behaviour of these events over the past 50–100 yr and often less. Critical to these determinations is an understanding of the full extent of the natural variability of this hazard. The coarse resolution of millennial scale sedimentary records, brevity of the instrumental register, imprecision of longer historical accounts and lack of any long-term, high resolution records has led to the assumption that the total variability of tropical cyclone behaviour is encompassed within the seasonal to multi-decadal oscillations observed to date. We present a near 800 yr long, annual resolution isotope record of tropical cyclones in northeast Australia which displays marked centennial scale regimes. Our record demonstrates that the frequency variability of intense landfalling cyclones is greatest at centennial scale compared to seasonal and decadal oscillations. Switching between centennial scale regimes in this record occurred rapidly (10–20 yr) highlighting the importance of accounting for this phenomenon in coastal planning and risk assessment. Our study highlights the importance of obtaining high resolution multi-century records of tropical cyclone activity in order to more accurately assess future impacts of this hazard to human society.

Analysis of aerial photographs and historic charts indicates that the barrier beach at Brigantine, NJ has migrated landward 300 to 400 m since 1869, primarily as a result of overwash during hurricanes and winter storms. A series of vibracores from the backbarrier salt marsh reveals a millennial-scale stratigraphic record of overwash deposition. Carbon-14 (C-14) and Cesium-137 (Cs-137) radioisotopic methods were used to date overwash deposits (washovers). The ages of recent washovers are consistent with deposition during intense storms in 1938, 1944, 1950, and 1962. An additional overwash deposit recovered in five of the sediment cores was likely deposited by an intense hurricane strike in 1821 or possibly in 1788. Two prehistoric overwash fans were likely deposited by intense storms striking the New Jersey Coast in the 7th to 14th centuries and 6th to 7th centuries A.D. The landward barrier migration indicates that the older overwash sediments were likely transported a considerably greater distance than the more recent overwash fans. The greater distance of transport may indicate that the prehistoric storms that deposited overwash fans across the study site were more intense than the most intense storm to strike this coast in the historic period, the hurricane of 1821. The spatially variable occurrence of overwash deposition at this site points to a need for multisite stratigraphic surveys of extensive stretches of the coast in order to develop reliable records of past intense storm frequency from backbarrier environments.

Micropaleontological analysis of four vibracores from back-barrier marshes of Folly Island, South Carolina, detected intervals of storm-deposited sediment. Individual washover intervals were not detectable from lithology alone, but only in conjunction with associated foraminifera. Washovers contained more modern offshore and Oligo-Miocene genera and total calcareous foraminifera than `background' marsh samples. The presence of Tertiary foraminifera in the back-barrier cores from Folly Island supports the hypothesis that much of the sediment for barrier island migration is derived from offshore. Foraminiferal analyses of back-barrier cores were also used to calculate relative bioturbation rates by the method of Officer and Lynch [Officer, C.B., Lynch, D.R., 1983. Mixing, sedimentation rates and age dating for sediment cores. Mar. Geol. 46, 261–278, eqs. 10–14]. In all cores, the current depositional environment correlated well with the expected mixing parameter ( G ): the highest mixing parameter (greatest signal attenuation) was recorded in a core from a low-marsh/creek-side environment whereas the lowest mixing parameter (least smearing of signal) was recorded in a high-marsh core.

More than 40 short cores were collected from 10 localities in the Myrtle Beach to McClellandville coastline of South Carolina. The localities were selected on the basis of whether or not they should have a well preserved record of recent hurricanes, most notably Hugo , which occurred in September, 1989. Of the 40 cores collected, results from two sites are presented here as examples — Price’s Inlet, a non-tidal intra-beach ridge area, which was directly in the path of the eyewall of Hugo , and Sandpiper Pond which is a coastal non-tidal pond near Murrells Inlet, about 50–75 km north of where the main landfall of hurricane Hugo but still in the area of high storm surge. These cores were analyzed for percentage organic carbon, visual observations, X-rays, and microfossils. The microfossils were used to differentiate marine/non-marine sequences in the non-tidal inlets and identify reworked sediments by means of displaced benthic foraminifera. Cores were dated using Pb-210 techniques that provide resolution for the last 100 yr. In Price’s Inlet the Hugo effect was most pronounced with an 8 cm thick sand layer containing many nearshore foraminifera, showing transport from offshore. In Sandpiper Pond we could see the trace of Hugo from the offshore foraminifera contained in sediments sandwiched between the freshwater intervals both before and after Hugo , however, there was little detectable trace in the X-rays or sedimentology of this core to indicate a storm event. Hence, we can recognize a range of responses for hurricanes in the form of different types of sediment layers and microfossil assemblages in these non-tidal areas depending on where the impact point is on the coast. Here we are able to distinguish at least two types of signals from the same storm which has significant implications for detecting these events in the pre-historic record and determining their paleo-periodicity.

The stable isotopic ratio of precipitation from tropical cyclones is very low compared to that of normal summer precipitation ( Lawrence and Gedzelman, 1996 ). Tropical Storms Allison and Chantal made landfall in southeast Texas in the summer of 1989 and dumped large amounts of rain. Isotope ratios of surface waters measured at five different sites decreased markedly after the passage and remained low for a few weeks. The return of isotope values to normalcy following these storms varied from site to site reflecting differences among the hydrological environments. During other summers from 1985 to 1993 isotope ratios of rains were higher and in the normal range. Calculations using air temperatures and oxygen isotope measurements of the surface waters show that organically precipitated fresh water carbonate should have recorded the two oxygen isotopic spikes produced by Allison and Chantal at all five sites. This suggests that isotopic analysis of ancient fresh water fossil carbonate shells, fossil mammal teeth or tree rings might be used to document past tropical cyclone activity.