Wednesday, August 5, 2009

Spectacle Island

Hello again everyone, hope everyone enjoyed Spectacle Island. My group examined 2 sites: one mid-beach and one right below the dune scarp high up on the beach. We found the overall, in both sites, the order of colored beach glass, from most abundant to least abundant, was: clear, amber, green, china remnants, blue, and red. However, in the area right below the dune, we found absolutely no red and very little red compared to the mid-beach site. Also, the pieces in the dune area were individually significantly bigger than those found mid-beach. I think this is due to the erosion of the beach and the sorting of different sized objects as they move down the beach. First, a storm wave erodes part of the dune, exposing some of the dumping ground underneath the sand, washing the beach glass down the beach. Since the bigger pieces of beach glass are heavier and require more energy to move, they remain relatively close to the dune, while the smaller pieces are easily swept down-beach by average-sized waves. I also noticed that the beach glass at the surface of our site was larger than the pieces i found by digging a little, which i am attributing to the Brazil nut effect. Aside from the size differences, however, there was little difference in the amount and color distribution of the sea glass between the two sites. As for background sand, there were more shells in the mid-beach section since the waves move over this area of the beach much more frequently and wash ashore shells and parts of shells. There were also pieces of dried grass and sticks on the dune site, simply because they fell from the dune and dried up in this area prior to being swept away by waves. Unfortunately i don't have any pictures to post since i forgot my camera today, but other members of my have some.

See you all tomorrow,
Sam Gifford

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