Wednesday, August 4, 2010

Treasures of Spectacle Island

For those of us stranded on Spectacle Island it was a welcome sight to see that there was no in depth blog post for the night. However, I had a few quick thoughts that I wanted to share:

1) Material from the landfill seemed to be coming to shore both by washing in from farther out and from being slowly excavated by the erosion of sediments on top of it. Around the southern side of the island many large pieces of scrap metal seemed to be slowly emerging from the sand while the small pieces of glass and ceramic seemed to be washing up onto the beach.

2) The Brazil nut hypothesis: In a vertical column of water the larger material will settle to the bottom and increasingly smaller material will settle towards the top. In a horizontal environment like a beach, however, the smaller and lighter material like sand and pieces of sea glass are easily washed down the beach by wave action while larger debris and rocks are too heavy to move and are left higher up on the beach.

3) At first glace the exposed substrate on the island looks like the same glacial till that was on Lovell's. If you look closer though you will see pieces of seas glass, shells, and other artifacts embedded in the sediment. This would cause serious problems to the theory of geological succession if we did not know the true history of the island. The till looks primarily the same because of the waste material from the central artery construction. A lot of the bedrock of Boston and the harbor is the glacial till like on Lovell's. It was dumped to create Spectacle Island but during the dredging and landfill process pieces of the fill, shells, etc were incorporated into the sediment.

4) I think that part of the Day 1 harbor orientation tour Bruce should take the students to teh top of the North Drumlin on Spectacle Island. The view provides a much better layout and understanding of the geography of the bay, horbor, coast, and islands than taking a boat tour does.

Looking forward to eating some striped bass tomorrow!

Alex Beach

1 comment:

Bruce Berman said...

Excellent suggestion, Alex - did you guys take any photos?