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The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton , began to split apart during the Mesoproterozoic era of the Precambrian , about 1.1 ...
The Newark Supergroup, also known as the Newark Group, is an assemblage of Upper Triassic and Lower Jurassic sedimentary and volcanic rocks which outcrop intermittently along the east coast of North America. They were deposited in a series of Triassic basins, the Eastern North American rift basins, approximately 220–190 million years ago.
NASA satellite photo of typical Basin and Range topography across central Nevada. The Basin and Range Province includes much of western North America.In the United States, it is bordered on the west by the eastern fault scarp of the Sierra Nevada and spans over 500 miles (800 km) to its eastern border marked by the Wasatch Fault, the Colorado Plateau and the Rio Grande Rift.
Though the north-eastern end of the basin is well-defined (it ends at the Hudson River), 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.
The rift zone known as the mid-Atlantic ridge continued to provide the raw volcanic materials for the expanding ocean basin. [20] North America was slowly pulled westward away from the rift zone. The thick continental crust that made up the new east coast collapsed into a series of down-dropped fault blocks that roughly parallel today's coastline.
A physiographic province is a geographic region with a characteristic geomorphology, and often specific subsurface rock type or structural elements. The continents are subdivided into various physiographic provinces, each having a specific character, relief, and environment which contributes to its distinctiveness.
Eastern North America Rift Basins – Assemblage of Upper Triassic and Lower Jurassic sedimentary rocks Fundy Basin – Sediment-filled rift basin on the Atlantic coast of southeastern Canada Gulf of Suez Rift – Continental rift zone that was active between the Late Oligocene and the end of the Miocene
Most included all of North America without regard to political subdivision. Fenneman expanded and presented a derivative of this system more fully in two books, Physiography of western United States (1931), [7] and Physiography of eastern United States (1938). [8]