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How did Late Triassic rifting affect eastern North America?
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Triassic Period
Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the early Triassic Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.
During the Late Triassic, the onset of continental rifting caused the Earth's crust to stretch along the Appalachian Mountain belt in eastern North America, extending from the Carolinas to Nova Scotia.1
This tectonic activity resulted in several significant geological changes:
- Normal Faulting and Basin Formation: The stretching of the crust led to normal faulting, creating grabens, or fault-bounded basins.1
- Sedimentation: These basins received thick sequences of clastic (rock fragment) sediments derived from the erosion of the nearby Appalachian Mountains.1
- Igneous Activity: The region was subsequently intruded by igneous dikes and sills.1
- Newark Group: This sequence of rocks, known for its dinosaur tracks and fossils of freshwater organisms, provides evidence of these processes, as its unmetamorphosed state indicates it was deposited following the main phase of the Appalachian orogeny.1
This rifting was part of the broader fragmentation of the supercontinent Pangea, which eventually led to the opening of the Atlantic Ocean.1