I hadn't taken into account that water has a way of exploiting a weak point. On geologic maps, a black line with arrows on one side suggests one slab of rock has slid underneath another. I convinced my wife to drive out to the site of the fault, with the added enticement that it intersected the coast. A trip to the beach, on a day above 40 in the winter was not to be passed up. We pulled into Ocean Park, and while my wife fed my son, I scouted the site.
What I hoped to see was a reunion. Five hundred million years ago the rock to the south of Ocean Park and the rock to the north found their home on the fringe of a continent called Gondwana. The goliath Gondwana covered an area of Earth a tad bigger than modern Asia centered around the South Pole. If Gondwana was Asia, then Biddeford and the rock to the south of Ocean Park were part of Japan; Old Orchard, and the rock to the north,the coast of China. Four hundred ninety million years ago, plate tectonics ripped Gondwana apart. These hunks of land set sail across the proto-Atlantic, their near hundred million year journey landing them on Maine's coast 400 million years ago. Unfortunately, tectonics did not set them gently on the coast. The force of the plates shoved the edge of the Biddeford land mass underneath the one that underlies Old Orchard. In a moment I could see Gondwana reunited on Maine's shores.
As I climbed the dune to get a view of this collision, I'd already began to lose hope. The wind blown sand pointed to the fact that no natural bedrock hindered the movement of sediment. Cresting the dune, I saw beautiful beach for miles in either direction, but no fault. My wife enjoyed the beach, my son gleefully played in the sand and I pursued the only rock bigger than a pebble, only to be chased away by cold waves. I looked up the beach at Prout's Neck, and down at Biddeford Pool, wistfully considering my chances of convincing my wife to add some miles to our trip. If I could just see the rocks on either end, I might find evidence of the Gondwanan meeting point. Why were they so far away?
A wave hit the shore and my mind traveled back that 400 million years. That wave would have hit the junction of those collided islands. It would have found the minute space in between that ancient Japan and that forgotten China. As it rushed in it would have torn away the smallest piece of sediment. As it poured out, it would have stolen another. The space in between would have grown larger and larger. Grain by grain it would be filled in with the small fragments that were broken away. For 400 million years, the trend would continue. The end point of this scenario had become clear.
As we walked back down the beach, on the way to our car, I looked at Biddeford Pool and Prout's Neck as stalwart survivors of an intense collision, then a slow bleed. Each a reminder of a reunion too long ago to have withstood the relentless abrasion of water.
Dorais, Michael J., Robert P. Wintsch, Wendy R. Nelson, and Michael Tubrett. "Insights Into The Acadian Orogeny, New England Appalachians: A Provenance Study Of The Carrabassett And Kittery Formations, Maine." Atlantic Geology 45.0 (2009): 50-71. Print.
"Geology of Massachusetts." Wikipedia. Wikimedia Foundation, 22 Feb. 2014. Web. 16 Mar. 2014. <http://en.wikipedia.org/wiki/Geology_of_Massachusetts>.
Nance, R. Damien. "Late Precambrian–early Paleozoic arc-platform transitions in the Avalon terrane of the Northern Appalachians; Review and implications."Geological Society of America Special Papers 245 (1990): 1-12. Print.
Osberg, Philip H., Hussey, Arthur M., II, and Boone, Gary M. (editors), 1985, Bedrock geologic map of Maine; Maine Geological Survey (Department of Conservation), scale 1:500,000
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