Geology of New Jersey
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The Geology of New Jersey consists of four distinct physiographic provinces. They are: (listed from the south to the north) the Atlantic Coastal Plain Province, the Piedmont Province, the Highlands Province, and the Ridge and Valley Province.
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[edit] Coastal Plain
The largest province in the state, encompasses the southeast part of the state below the fall zone from Trenton to Woodbridge. It contains a large wedge of unconsolidated sediments that have been deposited since the Cretaceous Period. These sediments continue off-shore until the continental shelf edge in the Atlantic Ocean. Topography is relatively flat with a few hills of erosion resistant sediments containing gravel or iron-sedimented sands.[1] The province is divided further into three subprovinces: the Lowland section which are flat, often inundadted areas of tidal marshes, back bays, and barrier islands. This section generally follows the coastline, Delaware Bay, and Delaware River. The intermediate upland section are raised areas inland and are best suited for farming and other agriculture. The sands of the coastal plain have been mined for foundry sand and sand used for glass making. And finally, the upland section; which home to the New Jersey Pine Barrens and Fort Dix. Glauconite is commonly found in this section, especially around Freehold Township, New Jersey.[2]
[edit] Piedmont
A majority of the rocks in this province are a part of the Newark Supergroup. They include the Passaic Formation, the Lockatong Formation, the Stockton Formation, and the igneous rocks basalt and diabase. In New Jersey, more basalt flows are evident with several named formations including the Hook Mountain Basalt, the Preakness Basalt, and the Orange Mountain Basalt. Diabase is prominently displayed along the Hudson River in the Palisades Sill. These rocks were deposited during the rifting of Pangea during the Triassic and Jurassic Periods. Much of the northern segment of this region was glaciated and the resultant shaping help to form New York and Newark harbors.
A small portion of the Pennsylvania Peidmont Highlands called the Trenton prong extends into New Jersey through Trenton and are mostly Ediacaran and Cambrian aged rocks, that includes the Wissahickon Formation. The Manhattan Schist exists in New Jersey, largely below New York harbor and in the vicinity of Bayonne and Jersey City.[2]
[edit] Highlands
This section contains some the oldest rocks in New Jersey and is largely a mix of Pre-Cambrian granites and gniesses and lower Paleozoic clastic and carbonate rocks.[2] The harder granites and gneisses produce steep sided hills and mountains since they are relatively resistant to erosion. There are two small klippes in the southern part of this province, the Jutland klippe south of Musconetcong Mountain and the Peapack klippe in southern Morris County.
There are numerous active and abandoned mines in this area because of its rich mineral wealth. Iron, zinc, and marble were all important minerals mined from the New Jersey Highlands. Franklinite is a mineral first described at Sterling Hill mine.
[edit] Green Pond Mountain
This area extending from Northern Passaic County and into western Morris County is a slice of Lower Cambrian to Middle Devonian rocks that are collected in a half graben and are detached from the Valley and Ridge sequence. These rocks have always been described separately from the rocks in the Valley and Ridge, but have been cross-correlated to those rocks.
[edit] Ridge and Valley
The smallest province in the state, it is confined to the northwest corner of the state. The Kittatinny Valley is a part of the Great Appalachian Valley and contain the oldest rocks of the province. Beyond this ridge, there are series of rolling hills and small ridges underlain by Silurian and Devonian aged rocks. The Delaware River is deflected by ridges and travels generally southwest, along the strike of the upturned beds of sedimentary rock. The Delaware flows in a riverbed of glacial till in the Minisink and Walpack buried valleys, formed from erosion of softer bedrock, then passes through the Delaware Water Gap in Kittatinny Mountain,[3] a continuation of Blue Mountain in Pennsylvania. The buried valleys extend beyond the riverbed and stretch across the state from Pennsylvania to New York.[4] The limestones in this area also exhibit karst topography, including sinkholes and small caves.[3]
[edit] Geologic Features
- Delaware Water Gap
- New Jersey Palisades
- Sterling Hill
[edit] Notable Rock Formations
- Lockatong Formation
- Passaic Formation (former Brunswick Formation)
- Stockton Formation
- Marcellus Formation
[edit] References
- ^ http://www.state.nj.us/dep/njgs/enviroed/freedwn/psnjmap.pdf
- ^ a b c Orndorff, R.C., et.al, (1998). Bedrock Geologic Map of Central and Southern New Jersey. United States Geolgic Survey, Scale 1:100,000.
- ^ a b White, Ron W.; Monteverde, Donald H. (2006-02-01). Karst in the Delaware Water Gap National Recreation Area (pdf). Unearthing New Jersey Vol. 2, No. 1. New Jersey Geological Survey. Retrieved on 2008-06-07.
- ^ White, I.C.; Chance, H.M. (1882). The geology of Pike and Monroe counties, Second Geol. Surv. of Penna., Rept. of Progress, G6, pp. 53-57.
[edit] External links
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