page_title: Staten Island
section_title: Geology
hierarchical_section_title: Staten Island / Geology
caption_attribution_description: English: Geological map of Staten Island, New York
context_page_description: Staten Island is a borough of New York City, coterminous with Richmond County, in the U.S. state of New York. Located in the southwest portion of the city, the borough is separated from New Jersey by the Arthur Kill and the Kill Van Kull and from the rest of New York by New York Bay. With an estimated population of 476,143 in 2019, Staten Island is the least-populated of the boroughs but is the third-largest in land area at 58.5 sq mi. The borough also contains the southern-most point in the state, South Point. If each borough were ranked as a city, Staten Island would rank as the 39th most-populous in the U.S.
  Staten Island joined New York City in 1898, and was referred to as the Borough of Richmond until 1975. Staten Island has sometimes been called "the forgotten borough" by inhabitants who feel neglected by the city government.
  The North Shore—especially the neighborhoods of St. George, Tompkinsville, Clifton, and Stapleton—is the most urban part of the island; it contains the designated St. George Historic District and the St. Paul's Avenue-Stapleton Heights Historic District, which feature large Victorian houses. The East Shore is home to the 2.5-mile F.D.R.
context_section_description: During the Paleozoic Era, the tectonic plate containing the continent of Laurentia and the plate containing the continent of Gondwanaland were converging, the Iapetus Ocean that separated the two continents gradually closed, and the resulting collision between the plates formed the Appalachian Mountains. During the early stages of this mountain building known as the Taconic orogeny, a piece of ocean crust from the Iapetus Ocean broke off and became incorporated into the collision zone and now forms the oldest bedrock strata of Staten Island, the serpentinite.
  This strata of the Lower Paleozoic (approximately 430 million years old) consists predominantly of the serpentine minerals, antigorite, chrysotile, and lizardite; it also contains asbestos and talc. At the end of the Paleozoic era (248 million years ago) all major continental masses were joined into the supercontinent of Pangaea.
  The Palisades Sill has been designated a National Natural Landmark, being "the best example of a thick diabase sill in the United States." It underlies a portion of northwest Staten Island, with a visible outcropping in Travis, off Travis Road in the William T. Davis Wildlife Refuge. This is the same formation which appears in New Jersey and upstate New York along the Hudson River in Palisades Interstate Park. The sill extends southward beyond the cliffs in Jersey City beneath the Upper New York Harbor and resurfaces on Staten Island. The Palisades sill date from the Early Jurassic period, 192 to 186 million years ago.
  Staten Island has been at the southern terminus of various periods of glaciation. The most recent, the Wisconsin glaciation, ended approximately 12,000 years ago. The accumulated rock and sediment deposited at the terminus of the glacier is known as the terminal moraine present along the central portion of the island. The evidence of these glacial periods is visible in the remaining wooded areas of Staten Island in the form of glacial erratics and kettle ponds.
  At the retreat of the ice sheet, Staten Island was connected by land to Long Island, as the Narrows had not yet formed. Geologists' reckonings of the course of the Hudson River have placed it alternatively through the present course of the Raritan River, south of the island, or through present-day Flushing Bay and Jamaica Bay.
caption: The geology of Staten Island.
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