The Newark Basin is a

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

-filled rift basin located mainly in northern

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

but also stretching into south-eastern

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

and southern New York. It is part of the system of Eastern North America Rift Basins.

Geology

Approximately 220 million years ago, during the late

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

Period, the

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...

Pangaea Pangaea or Pangea ( ) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from the earlier continental units of Gondwana, Euramerica and Siberia during the Carboniferous period approximately 335 mi ...

began to break apart. The focus of the rifting began somewhere between where present-day eastern

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

and north-western

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

were joined. As in all rifting environments,

graben In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...

s formed. Many of these grabens were created, but for some of them, extension stopped before full rifting occurred. Where only partial rifting occurred, basins formed, analogous to the present-day

Basin and Range Province The Basin and Range Province is a vast United States physiographic region, physiographic region covering much of the inland Western United States and Northern Mexico, northwestern Mexico. It is defined by unique basin and range topography, charac ...

in western United States. By definition, a basin is any area that collects sediments. These "aborted rifts" (rifts that are tectonically inactive and no longer collecting sediments) extend from

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...

. Along certain basins, rifting was not partial. Where full rifting occurred, the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

was created. It is important to note that along these rifts, magmatic activity never stopped, as shown by the ongoing eruption of lava along the

Mid-Atlantic Ridge The Mid-Atlantic Ridge is a mid-ocean ridge (a Divergent boundary, divergent or constructive Plate tectonics, plate boundary) located along the floor of the Atlantic Ocean, and part of the List of longest mountain chains on Earth, longest mountai ...

. The Newark Basin is one in a series of these failed rifts. It is a half-graben filled over time by characteristic red bed sediments, sediments eroded from the uplifted footwalls of the border faults that were deposited within the basin; they are red due to their abundance in oxidized iron oxide minerals. The border fault is the Ramapo Fault on the western boundary of the basin; this is where the hanging wall of the graben slid down to its current position. Estimates to the depth of accumulated sediments on the western side of the basin, and therefore the depth of the hanging wall, are in the area of 11,000 feet. The beds dip roughly 15 degrees to the west throughout the basin. Though the north-eastern end of the basin is well-defined (it ends at the

Hudson River The Hudson River, historically the North River, is a river that flows from north to south largely through eastern New York (state), New York state. It originates in the Adirondack Mountains at Henderson Lake (New York), Henderson Lake in the ...

), the south-western "end" is not an end at all, but merely a narrowing where the graben then re-opens into the Gettysburg Basin. A significant geological feature within the Newark Basin is the Palisades Sill. During rifting events, magmatism is common due to

decompression melting Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...

. The Palisades Sill is a result of this process. Image:Break-up of Pangaea.JPG, A USGS cartoon showing the break-up of Pangaea and the origin of the Newark Basin Image:Newark Basin Cross Section.jpg, USGS cross-section of the Newark Basin

References

Sources
"The Newark Basin"
on the

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...

website
"Mesozoic Basins"
on the USGS website {{Geology of the Newark Basin Geology of New Jersey Geology of Pennsylvania Geology of New York (state) Aulacogens Sedimentary basins of North America

Geology

See also

References