NOAA GOES-13 image of Sandy at 6:02 a.m. EDT Tuesday (Oct. 30, 2012). Accessed at http://www.livescience.com/24380-hurricane-sandy-status-data.html
How can we identify Hurricanes E. Christa Farmer , J Bret Bennington , Courtney Melrose , Will Berger , Nika Chery , Emma Kast , Steven Leone , in Long Island’s Tamunoisoala LongJohn , Ashley Persaud , Jacob Roday , Jeremy Silverman , Dayna Spero , and Sheetal Tolia barrier beach island sediments? 1
4
1
1
3
1
4
2
1
1
1
4
4
(1) Department of Geology, Hofstra University, 114 Hofstra University, Hempstead, NY 11549-1140, GEOECF@hofstra.edu (2) Stony Brook University, Stony Brook, NY 11794 (3) Department of Chemistry, Hofstra University, Hempstead, NY 11549 (4) Hofstra University Summer Science Program
to find out. Aerial photographs taken after historical hurricanes made landfall on Long Island show areas of “overwash,” or How can we identify signatures of past hurricane in Long coarser, sandy sediment deposited in the usually muddy marsh Island’s barrier beach island sediments? A collaboration of sediment. Collecting several sediment cores from Long Island’s faculty from the Hofstra Department of Geology Environment barrier beach islands indicates that these coarser layers can be and Sustainability, several Hofstra undergraduate students, and identified. Trace metal concentrations help identify the timing several local high school students participating in the Hofstra of these layers because these levels rise at the onset of University Summer Science Research Program have been trying industrialization.
Abstract:
Where do we collect sediment cores?
Location of Hofstra University (map courtesy of Google.com)
How do we collect cores? Step 1: Use concrete vibrator and heavy weight to drive irrigation pipe into the sediments of the barrier beach marsh. Step 2: Use ropes and student muscle to drive pipe as far as possible.
Step 3: Use farm jack to pry pipe back out.
Step 4: Use tin snips to cut pipe in half lengthwise to reveal sediment layers.
This map shows the location of our field site in Hampton Bays, NY, where sediment cores were collected from 2011 to 2013. The inset image is an aerial photograph taken in 1938 after the “Long Island Express” hurricane made landfall (image from http://rsm.usace.army.mil/shore/). You can see tongues of sandier sediment, which shows up as white in the image compared to the darker marsh sediment and vegetation, that have been thrown over the beach berm onto the bay side marsh.
What have we found? We recovered a piece of glass from 55-60cm depth in TB1A, which turned out to be half of the bottom of a bottle that contained the marking indentifying the manufacturer of the bottle, where it was made, and in this case the most likely year (1937) in which it was made. This find was recovered from a layer of sediment that lies immediately under a coarse sediment layer. We thought this layer represented the overwash from the 1938 “Long Island Express” hurricane, until we were able to compare the grain size characteristics of this layer with those of the overwash deposited by Superstorm Sandy. The trace metal concentrations, however, are still consistent with the stratigraphy: they rise after the onset of industrialization.