Paper No. 38-11
Presentation Time: 11:30 AM
ASSESSMENT OF BEACH SAND COMPOSITION: PRE-AND-POST HURRICANE SANDY, ROCKAWAY, QUEENS, NEW YORK CITY
This study involves sedimentological and mineralogical investigation of representative beach sands collected from Rockaway beach, Queens, New York City in order to assess the difference in grain size and compositional variability due to the pre-and-post Hurricane Sandy-dominated environmental setting. Geologically, it is very significant to determine the grain size and composition of sands in order to trace their origin and establish the depositional environment as well. Preliminary conclusions based on grain size data from representative sand samples display an apparently anomalous grain-size frequency between the pre-and-post Hurricane Sandy influenced sand deposits. Pre-Sandy deposits are better sorted and moderately oxidized due to the prolonged shoreline depositional processes. Post-Sandy deposits are moderately to poorly sorted and very often display dominance of medium to coarse sand compared with pre-Sandy deposits. Detrital quartz associated with both pre-and post Hurricane Sandy also displayed marked textural and weathering phenomena. Most of the representative samples obtained from pre-Hurricane Sandy had well-rounded quartz grains, whereas post-Hurricane Sandy had a greater proportion of mixed quartz fabric including subrounded to rounded grains and a preponderance of freshly broken shell assemblages. To draw a more conclusive and sedimentologically viable explanation, further mineralogical and geochemical investigations are underway since they have direct bearing on the geological consequences and changing landscape phenomena. Recent climate change is apparently affecting coastal geology and reshaping the landscape and warranting greater emphasis to be focused on geology as one of the controlling factors influencing coastal landscape, particularly on the east coast of the U. S.