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In geology, a terrane (/ t ə ˈ r eɪ n, ˈ t ɛr eɪ n /; [1] [2] in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or "sutured" to crust lying on another plate. The crustal block or fragment preserves its distinctive geologic history, which is different from the ...
The Yakutat Terrane is currently colliding with the continental margin below the central Gulf of Alaska. During the Neogene the terrane's western part was subducted after which a sediment wedge accreted along the northeast Aleutian Trench. This wedge incorporates sediment eroded from the continental margin and marine sediments carried into the ...
In geology, accretion is a process by which material is added to a tectonic plate at a subduction zone, frequently on the edge of existing continental landmasses. The added material may be sediment, volcanic arcs, seamounts, oceanic crust or other igneous features. [1] [2] [3]
In structural geology, a suture is a joining along a major fault zone, of separate terranes, tectonic units that have different plate tectonic, metamorphic and paleogeographic histories. The suture is often represented on the surface by an orogen or mountain range. [1]
Lifted fault-block geology Tilted fault-block formation in the Teton Range. Fault-block mountains often result from rifting, an indicator of extensional tectonics. These can be small or form extensive rift valley systems, such as the East African Rift zone. Death Valley in California is a smaller example.
Laurentia basement rocks. Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America.Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and the Hebridean Terrane in northwest Scotland.
When mapping the metamorphic grade of a terrane, a geologist has to take the lithology of the rock in account. Lithologies are mainly dependent on the protolith, the original rock before metamorphism. The main lithologies are ultramafic, mafic, felsic (or quartzo-feldspathic), pelitic and calcareous. In all of these (and other) lithologies ...
An example of using thermal modeling in P-T-t path reconstruction. The above diagram shows the calculated geothermal gradients upon crustal thickening at 0 million year (m.y.) followed by an immediate uplift event at a rate of 1 mm per year. The P-T-t evolution of a rock originally at 40 km below ground is marked as red dots on the diagram.