During late Paleozoic time the ancient Iapetus Ocean (also called Proto-Atlantic Ocean) continued to vanish as North America collided with Africa. During this time all of the Earth's continents were coalescing to form the supercontinent, Pangaea (beginning roughly 320 million years ago during the Pennsylvanian Period). In eastern North America the formation of Pangaea corresponded to the Alleghenian Orogeny, the mountain-building episode associated with the formation of great folds and thrust faults throughout the central Appalachian Mountains region. The erosional characteristics of the sedimentary rock formations exposed along great anticlines and synclines of the Appalachian Mountains are responsible for the characteristic Valley and Ridge topography. Durable layers of sandstone and conglomerate form ridges, whereas less resistant limestone and shale underlie the valleys in the region.

The greatest amount of deformation within the Valley and Ridge Province occurred in the Southern Appalachians (North Carolina, Tennessee, Virginia, and West Virginia). The fold belt extends northward through Pennsylvania and peters out north of the New York border. The Kittatinny Mountains in northwestern New Jersey mark the northeasternmost extension of the high ridges of the Valley and Ridge Province.

Before and during the Appalachian Orogeny Carboniferous age (Mississippian and Pennsylvanian) coal-bearing sedimentary rocks in eastern Pennsylvania formed from sediments deposited on a swampy alluvial plain along the western margin of a high mountain range. This folded mountain belt formed along the convergent collision zone between Africa and North America (the Atlantic Ocean did not yet exist!). High mountains probably existed in the region east of the fold belt, referred to as the Atlantic Piedmont. The Piedmont is an area east of the folds, and is partially buried by younger sediments including the relatively geologically "younger" deposits of the Newark Basin and the Coastal Plain. The deformation associated with the Appalachian Orogeny no doubt created major fault systems in the region and subjected the rocks currently buried beneath the Newark Basin and the Coastal Plain to intense deformation. With the passage of time the great mountain belt that existed between Africa and North America have long since eroded away.

Rocks of Mississippian, Pennsylvanian, and Permian age are not known to exist in the New York City region. A great unconformity beneath the Triassic sedimentary rocks of the Newark Basin series represents an extensive period of erosion of uplifted rocks and sediments during and after the Appalachian Orogeny. This unconformable surface is flooded beneath the lower Hudson River below the Palisades.

The occurrence of an abundance of coal on area beaches is an indication that the Valley and Ridge Province is a source of sediment (both naturally and by human activity). Evidence that coal is not entirely of anthropenic origin on area beaches is suggested by historical evidence: "October 9, 1677, John Thompson of Setauket has a permit to go to Flushing and other ports of Long Island to search for sea coal, of which he hath probable information" (Hint, 1967). This very early report shows that ample amounts of coal already existed on area beaches long before the mining of coal in the region had begun. The low density and hard character of Appalachian coal allows it to survive long distance transport via rivers that drain the Appalachian region into the Atlantic. Through time, the Delaware River has transported sediments from the Valley and Ridge region onto the Atlantic coastal region via the Delaware Water Gap. (In the past other rivers in the region have contributed sediments from the Valley and Ridge region as well). The existence of coal in Cretaceous and younger sediments is evidence that Valley and Ridge area sediments have been deposited and reworked into progressively younger sediments, including modern beach deposits.


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Writers and Webmeisters:

Phil Stoffer and Paula Messina

CUNY, Earth & Environmental Science, Ph.D. Program
Hunter College, Department of Geography
Brooklyn College, Department of Geology

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Copyright September, 1996 (All rights reserved; use as an educational resource encouraged.)>