Nine Vibracores from the backbarrier marsh at Whale Beach, New Jersey, reveal
three large-scale overwash deposits associated with historic and prehistoric
storms. The uppermost and smallest overwash fan was deposited in the Ash Wednesday
northeaster of March 5–8, 1962. A second more substantial overwash fan
between 100 and 35 cm depth dates to the late eighteenth or early nineteenth
century. This fan was most likely deposited during the 1821 hurricane, the only
intense hurricane to make landfall in New Jersey in the past 350 years. A third,
larger overwash fan between 200 and 300 cm depth was deposited between A.D.
1278 and 1438 and is likely the result of a prehistoric intense hurricane strike.
The combination of historical and stratigraphic evidence indicates that two
intense hurricanes (winds >50 m s-1) have likely made landfall on the southern
New Jersey coast in the past 700 yr, resulting in an annual landfall probability
of 0.3%.
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Figure 1. Location of Whale Beach study site (square) on southern New Jersey coast and approximate track of September 3, 1821, hurricane (inset). Whale Beach backbarrier marsh study site core locations are noted with numbers (photograph taken in 1994; courtesy of the U.S. Geological Survey). AC is Atlantic City, OC is Ocean City, an SIC is Sea Isle City. |
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Figure 2. Aerial photographs of Whale Beach Marsh from 1940, 1961, and 1963 (source: State of New Jersey, Department of Environmental Protection). Area from where sediment cores were extracted is denoted with white squares (see Fig. 1). Dashed line represents position of marine edge of beach in 1842 Coast and Geodetic Survey Chart. Open arrow in 1940 photograph denotes vegetated pre-1932 overwash fan to northeast of core locations. |
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Figure 3. Core logs from Whale Beach Marsh. Each core is separated by 50 m and is plotted to illustrate stratigraphy in three dimensions. Open triangles denote stratigraphic interval where native weed pollen increases, indicating widespread European-style clearance of landscape (ca. A.D. 1700). Downward-pointing arrows denote stratigraphic interval where chestnut pollen decreases (ca. A.D. 1920). Asterisk marks interval in core 3 where activity of 137Cs peaks, indicating deposition ca. A.D. 1963. Solid arrows with numbers mark locations of radiocarbon-dated samples (dates and 2 s calibrated age ranges presented in Table 1). 2 s calibrated age ranges are plotted at bottom; numbers to right indicate sample. Gray lines represent portions of calibrated ranges that can be eliminated based on pollen results. Shaded area denotes mutual overlap of remaining highest probability age ranges. |
