The Late Quaternary Construction of Cape Cod, Massachusetts: A Reconsideration of the W. M. Davis Model
Elazar Uchupi, G.S. Giese, D.G. Aubrey, D.-J. Kim, 1996. "The Late Quaternary Construction of Cape Cod, Massachusetts: A Reconsideration of the W. M. Davis Model", The Late Quaternary Construction of Cape Cod, Massachusetts: A Reconsideration of the W. M. Davis Model, Elazar Uchupi, G.S. Giese, D.G. Aubrey, D.-J. Kim
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Like the W. M. Davis construction of Cape Cod published in 1896, this special paper suggests that the Cape was formed by glacial deposition during the late Pleistocene and by marine and aeolian processes during the Holocene. It differs, however, from the Davis model in several significant ways. For example, Davis proposed that the lower Cape extended 4 km east of its present location, and that only 4,000 yr were needed for the lower Cape to attain its present form. This study indicates that the glacial Cape extended as far as 7 km east of its present position, and that it took about 9,500 yr for the Cape to attain its present morphology. Davis also believed that the detritus eroded from the sea cliffs on the east side of the lower Cape was transported northward to form the Provincetown Hook. On the other hand, this book indicates that, as a result of the subaerial exposure of Georges Bank from 9,500 to 6,000 yr ago, littoral drift to the north was inhibited and sediment was transported southward to fill a depression at the Cape's elbow. Since Georges Bank became submerged about 6,000 yr ago, however, littoral drift shifted partly to the north, leading to the construction of Provincetown Hook, a process that is still taking place today. The bulk of material (86%) eroded from the cliffs along the east side of the lower Cape during the last 6,000 yr was transported northward. Of the remainder, 7% was used in the construction of the beaches and offshore bars fronting the cliffs, and the remaining 7% was incorporated into the spits and barriers south of the cliffs. During the last 70 yr, the eastern Cape cliffs have been retreating at an average rate of 0.8 m a-1, a rate enhanced by a relative rise in sea level of about 2 to 3 mm a-1.