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Rift basin: Divergent: Rift basins are elongate sedimentary basins formed in depressions created by tectonically-induced thinning (stretching) of continental crust, generally bounded by normal faults that create grabens and half-grabens. [21] [22] Some authors recognize two subtypes: [4]
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]
Significant uplift of the rift shoulders develops at this stage, strongly influencing drainage and sedimentation in the rift basins. [ 8 ] During the climax of lithospheric rifting, as the crust is thinned, the Earth's surface subsides and the Moho becomes correspondingly raised.
Cratons of South America and Africa during the Triassic Period when the two continents were joined as part of the Pangea supercontinent. A craton (/ ˈ k r eɪ t ɒ n / KRAYT-on, / ˈ k r æ t ɒ n / KRAT-on, or / ˈ k r eɪ t ən / KRAY-tən; [1] [2] [3] from Ancient Greek: κράτος kratos "strength") is an old and stable part of the continental lithosphere, which consists of Earth's two ...
Satellite image of the Cayman Trough Bathymetric features of the Rockall Trough northwest of Scotland and Ireland. In geology, a trough is a linear structural depression that extends laterally over a distance.
Lake-filled half-graben showing sedimentation dominantly from the 'hinge' margin. Four zones of sedimentation can be defined in a half-graben. The first is "escarpment margin" sedimentation, found along the major border faults bounding the half graben, where the deepest part of the basin meets the highest rift-shoulder mountains. [6]
As mentioned above, the pre-rift stratigraphy of the central Gulf of Mexico basin, which now lies beneath nearly 20 kilometers of sediment deposited during the Jurassic through the Holocene, is made up primarily of extensional graben formations filled with "red beds," basalt flows, and diabase dikes and sills deposited and intruded during the ...
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 to Newfoundland. Along certain basins, rifting was not partial. Where full rifting occurred, the Atlantic Ocean was created.