Staten Island (Richmond County), New York City, New York, USAi

Regional Level Types
Staten Island (Richmond County)	Island
New York City	City
New York	State
USA	Country

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An island, borough of New York City, and county of New York State. Staten Island lies off the coast of New Jersey and S of the remainder of New York City.

A serpentine facies outcrops on Staten Island and the artinite and hydromagnesite are secondary minerals deposited in fracture surfaces due to weathering.

The large serpentinite body that outcrops in the northern part of Staten Island is the largest of a number of similar bodies that have been encountered in New York City and its immediate vicinity. Another serpentinite body of significant size outcrops a short distance north at Castle Point, Hoboken, New Jersey. It is possible that the two serpentinite bodies are separate outcrops of a single mass, the possible connection being hidden by the Hudson River and New York Bay. The Staten Island serpentinite occurs along a trend of serpentinites and other ultramafic rocks scattered along the inner edge of the Piedmont and in the southern Blue Ridge mountains over nearly the length of the Appalachians. Like most similar examples the Staten Island serpentinite is located near a major fault, known in the NYC area as Cameron's Line, which marks the over thrusting of deep water continental rise sediments and accreting terranes on to the outer edge of the continental margin. The tectonics involved in this process are complex and fragments of deeper oceanic and upper mantel crust often become entrained in the movement of huge masses of material toward the continent.

Occasionally, oceanic crust and upper mantle sequences make it onto the continent more or less intact. These are known as ophiolite complexes. In most cases the ophiolite sequences are completely dismembered and are seen in the geologic record as scattered fragments. This is the case with the serpentinites found in the New York area and further southwest in Pennsylvania and Maryland. Because the Staten Island serpentinite is an ophiolite fragment, transported a substantial distance just above a major regional thrust fault it has been heavily effected by ductile fractures. Younger brittle fractures are also abundant.

The Staten Island serpentinite was originally a dunite composed mainly of olivine and enstatite, a mineral assemblage stable at high temperature, high pressure, anhydrous conditions. In a more shallow, wetter environment the original mineral assemblage was hydrated and converted to that seen today. For a more complete description of the geology see Merguerian (2008) and Merguerian, C. and Moss, C. J. (2005 , 2007)

Another interesting aspect of the Staten Island serpentinite is the presence of “serpentine barrens”. These open, savanna-like areas were called “barrens” because the soils derived from the serpentine would not support agricultural crops. The most important factors limiting vegetation are the alkalinity of the soils and the low Ca/Mg ratio. A specialized community of plants has evolved to fill this niche.
Some of these are present in Staten Island although the “barrens” have been mostly built over and the few remaining fragments have been seriously degraded by human abuse. The geoecology of eastern serpentines is discussed in Rajakaruna, N., Harris, T. B. , and Alexander, E. B., (2009).

Commodity List

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Mineral List

Mineral list contains entries from the region specified including sub-localities

39 valid minerals.

Rock Types Recorded

Rock list contains entries from the region specified including sub-localities