Geologic Provinces of the United States: Appalachian
Highlands
Delaware River
Photo by Jack B Epstein, USGS
The Delaware River makes a sweeping bend as it heads throogh the
world-famous Delaware Water Gap. The bend of the river mimics the
underlying geology. The Shawangunk Formation of Silurian age,
comprising very hard quartzite and holding up Kittatinny Mountain,
dips moderately northward and is overlain by finer clastics of the
Bloomsburg Red Beds, also Silurian in age. The dip flattens out under
Dunnfield Creek (along which the Appalahcian Trail ascends the
mountain) beyomd which the Bloomsburg is thrown into a series
of small folds overlying a broader fold in the buried Shawangunk. The
bend in the river mimics the form of that anticlinal fold. Approximately
20,000 years ago, Wisconsinan glacialice occupied this valley and a
kame terrace of sand and gravel was deposited along Dunnfield Creek
(Qkt). The National Park Service visitor's center is located at the arrow.
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