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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 ...
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 ...
Formation of a metamorphic core complex. Metamorphic core complexes are exposed areas of deep crust brought to the surface by crustal extension (stretching). [1] They form, and are exhumed, through relatively fast [citation needed] transport of middle and lower continental crust to the Earth's surface [2] in the form of uplifting welts of hot rock and magma. [1]
Diagram (modified from Fig 3.11 in Irwin, 1990) showing the depositional setting of the Franciscan Assemblage and the contemporaneous Great Valley Sequence,. [ 5 ] The Franciscan Complex is an assemblage of metamorphosed and deformed rocks, associated with east-dipping subduction zone at the western coast of North America. [ 6 ]
Kodiak Shelf in the Gulf of Alaska – The geology of the Chugach National Forest is dominated by two major lithologic units, the Valdez Group (Late Cretaceous) and the Orca Group (Paleocene and Eocene). [15] The Valdez Group is part of a 2,200-km-long by 100-km-wide belt of Mesozoic accretionary complex rocks called the Chugach terrane. [16]
Chilenia was an ancient microcontinent or terrane whose history affected many of the older rocks of central Chile and western Argentina.It was once separated by oceanic crust from the Cuyania terrane to which it accreted at ~420-390 Ma when Cuyania was already amalgamated with Gondwana.
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.
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]