Tectono-stratigraphic terrane map of Alaska
- Geological Survey, Menlo Park, CA (United States)
- Geological Survey, Reston, VA (United States)
- Geological Survey, Anchorage, AK (United States)
A new terrane map compelled at a scale of 2.5 million is a comprehensive portrayal of the major tectono-stratigraphic terranes, pre-accretionary plutonic rocks, faults or sutures that bound terranes, and younger overlap sedimentary , volcanic, and plutonic assemblages of Alaska. Terranes are divided by tectonic affinity into cratonal, passive continental margin, metamorphosed continental margin, continental margin arc, island arc, oceanic crust, sea mount, ophiolite, accretionary wedge, subduction zone, turbidite basin, and metamorphic environments. Overlap assemblages consist of sequences of sedimentary, volcanic, and plutonic rocks that link or weld together adjacent terranes after emplacement, and provide important constraints on the timing of tectonic juxtaposition. Groups of terranes and overlap assemblages, with similar tectonic environments and geologic histories, can be correlated within Alaska and into the adjacent Canadian Cordillera. These groups include: (1) highly deformed and metamorphosed continental margin terranes (Seward, Coldfoot, Ruby, Yukon-Tanana, Kootenay) that are interpreted either as displaced fragments of the North American or other continental margins; (2) ophiolite terranes (Angayucham, Tozitna, Inoko, Seventymile, Slide Mountain) that are interpreted as remnants of one or more major, long-lived, Paleozoic and early Mesozoic oceanic basins; (3) Jurassic and Early Cretaceous island arc terranes (Koyukuk, Togiak, Nyac) that are interpreted as remnants of a discontinuous, short-lived, Mesoxoic island arc system; and (4) the Late Jurassic and Early Cretaceous Kahiltna and Gravina-Nutzotin overlap assemblages that are interpreted as parts of a major arc and flysch sequence.
- OSTI ID:
- 5099441
- Report Number(s):
- CONF-9305259--
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 25:5; ISSN GAAPBC; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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