A New Way to Explore: Rock Hunting on Cape Cod
How to spend vacations in Cape Cod
Beachcombing is a wonderful pastime and a great way to get better acquainted with your favorite Cape Cod beaches. While there are plenty of shells to discover, there are also many rocks to be found on the shores of Cape Cod. If you are wandering the beach in search of rocks, you may wonder what there is to find.
According to Steve Mabee of the UMass Geological Survey, the Cape doesn’t have many surprising rocks. However, the rocks that you can find on the Cape can make great additions to home décor, especially when combined with shells.
Mabee says that Cape Cod is made up of glacial sediments that were deposited during the last Ice Age. There is no exposed bedrock on Cape Cod because it is all 200 to 400 feet beneath the glacial sediments. Some larger rocks (Doane Rock, Hokum Rock) were left as the glaciers made their retreat. The bedrock that lies beneath the glacial sediments of Cape Cod is composed mostly of granite and gneiss (Mabee has a piece of the bedrock that was collected in a drill core taken from Falmouth at about 193 feet below sea level).
Mabee says that on the beaches, the most common rocks to find are “grayish, salt and pepper, granite, pink granite, layered gray gneisses, milky white quartz pebbles”. The reason the rocks are so common, according to Mabee, is because they are the ones that are most able to withstand the weathering and erosion from the waves. Occasionally beachgoers may find gabbros and basalts (black rocks), as well as felsite (reddish rock) and chert (cryptocrystalline quartz that is very fine grained and comes in a variety of colors).
Other items that may be spotted on the beaches include red bricks, hunks of old slag from smelting operations, sea glass, and driftwood. Keep your eyes open to find the perfect stones to bring back home with you.
BLOG | 04/02/2015 - 8:00AM | BY MATILDA BROWN
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