The earthcache is located within Maine Coast Heritage Trust’s Frenchboro Preserve. The island is accessible only by boat. There are very few services on the island so be prepared with the food and water you will need for the day. Here is a link to the ferry schedule.
This is an earthcache so there isn’t a container to find but instead you discover something about the geology of the area. To log this cache as found, you will visit Eastern Beach at the posted coordinates, view the geology of the beach, and then provide answers to a few questions.
GEOLOGY OF EASTERN BEACH
The rocks that make up Eastern Beach originated from the most recent glacial episode in Maine which began about 35,000 years ago, when the Laurentide Ice Sheet overspread southern Quebec and New England. During its peak development, this ice sheet was centered over eastern Canada and flowed east to southeast across Maine. It became several thousand feet thick and covered the highest mountains in the state. The weight of the glacier pushed the land downward several hundred feet. Rock debris was eroded and incorporated into the base of the glacier, causing the ice to abrade the bedrock surface over which it flowed. Climatic warming forced the Laurentide Ice Sheet to start receding as early as 21,000 years ago, soon after it reached its terminal position on Long Island, New York. The ice margin withdrew from the Gulf of Maine to the present position of the Maine coast by 17,000 to 16,000 years ago. It left behind glacial till which are chunks of rock fragments.
It took thousands of years for Eastern Beach to look the way it does now with cobblestones that cover the entire beach area. The force of the waves, constantly pushing the rocks up and down the beach, has rounded the jagged edges of the glacial till. The shoreline, formed by wave and tide action, is shallow and sloping which is somewhat resistant to erosion. The cobblestones located closer to the mean low water level are more subject to erosion during moderate and high wave action so are smaller in size than the cobblestones located closer to the mean high water level. The appearance of the beach changes over time due to the interplay of winds, waves, tides, and currents.
EARTHCACHE QUESTIONS
To get credit for this earthcache, you will need to send to me the answers to the following questions by email or Message Center.
1) Note the time of your visit and the tide level.
2) How high are the waves at the time of your visit? What do you see happening to the cobblestones as each wave hits the shoreline?
3) Estimate the average diameter of the cobblestones at the edge of the waterline.
4) Estimate the average diameter of the cobblestones at the mean high water line (next to ground zero)?
5) If the diameters estimated in questions #3 and #4 above are different, explain why. If the diameters are the same, explain why.
6) Why do you think the beach is sloped the way it is?
7) Is the geology of this area stable now or is it still undergoing change? Explain why.
8) Include a photo of yourself and/or GPSr with the beach and shoreline in the background.