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The igneous and metamorphic crystalline basement rock of New York formed in the Precambrian and are coterminous with the Canadian Shield.The Adirondack Mountains, Thousand Islands, Hudson Highlands, and Fordham gneiss, along with outcrops in the Berkshires just over the state line in Massachusetts, are part of the Grenville Province, a large piece of continental crust which accreted to the ...
It has been proposed that the Watchung basalt flows of the Watchung Mountains are extrusive eruptions of the same magma that created the Palisades Sill. Magnetic and gravity measurements have indicated the presence of a large subsurface dike between the Palisades intrusion and the Ladentown basalt, an extrusive body of Watchung basalt north of ...
Stark's Knob is a basaltic pillow lava formation near Schuylerville, New York, United States.It formed about 460 to 440 million years ago in relatively shallow sea water. It is often mistakenly referred to as a volcano, probably because early investigators described it as a volcano or volcanic plug.
Basalt (UK: / ˈ b æ s ɒ l t,-ɔː l t,-əl t /; [1] [2] US: / b ə ˈ s ɔː l t, ˈ b eɪ s ɔː l t /) [3] is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon.
The Newark Supergroup consists largely of poorly sorted nonmarine sediments; typical rocks are breccia, conglomerate, arkose sandstone, siltstone, and shale. [3] [4] Most of the strata are red beds that feature ripple marks, mud cracks, and even rain drop prints; dinosaur footprints are common, though actual body fossils are very rare. [4]
The cliffs stretch north from Jersey City about 20 miles (32 km) to near Nyack, New York, and are visible at Haverstraw, New York. They rise nearly vertically from near the edge of the river, and are about 300 feet (90 m) high at Weehawken , increasing gradually to 540 feet (160 m) high near their northern terminus. [ 1 ]
In this respect, the Ladentown basalt can be thought of as the remains of a fissure volcano, owing to the extrusion's slab-like character and ramping profile. New research indicates that the vicinity of Ladentown may have served as the primary vent from which the magma of the Palisades Sill erupted to the surface to form the Watchung flood basalts.
It has almost exactly the composition of a mixture of three parts harzburgite and one part tholeiitic basalt and is the likely source rock for basaltic magma. It is found as rare xenoliths in basalt, such as those of Kilbourne Hole in southern New Mexico, US, [15] and at Oahu, Hawaii, US. [16]