Definitions and images to illustrate geological terms, links to images and website articles


A terrane, as distinct from the more general topographic term 'terrain', is a crustal block or fragment that is typically bounded by faults and that has a geologic genesis distinct from those of surrounding areas.

In paleogeography, a terrane is the accreted block that has sutured to a craton (continental nucleus) and that contains distinct rock strata of distinct genesis. Thus, accreted terranes have become attached to continents as a result of tectonic processes. Superterranes are defined as composite terranes that comprise groups of individual terranes and other assemblages that share a distinctive tectonic history.

The Canadian Cordillera is an example of a complex, accreted terrane that is composed of five sub-parallel morphotectonic belts that result from Mesozoic and Cenozoic collision and deformation and accretion of allochthonous superterranes to the North American Craton. The Intermontane superterrane was accreted approximately 180 Ma, and the Insular superterrane was accreted approximately 100 Ma. The Coast Belt contains the suture resulting from the mid-Cretaceous collision between the exotic Insular superterrane and the previously accreted Intermontane superterrane. The accretionary suture was subsequently overprinted by the evolving subduction-related magmatic arc that persists as part of the modern Cascadia subduction zone. The Omineca belt represents the suture to the east of the Intermontane superterrane.

subduction zone magmas

[links: images: formations: rusty Archaean greenstones with gold mineralisation located adjacent to major Archean terrane boundary, Storø, Godthåbsfjord, Greenland; boudinaged pegmatites in Ordovician Hebron gneiss, a major rock type of the Merrimack terrane; Avalon Terrane Boundary, Deep River; maps: North America: Canadian Cordillera, 2, Great Slave Craton, SCLM (subcontinental lithospheric mantle) evolution beneath Slave Craton, cross-section of Buffalo Head Terrane; and terrane and tectonic elements, wNA, simplified; terranes associated with the Alaska Range (wp); Talkeetna Volcanic FormationPeninsula Terrane, south central Alaska, x-section; accreted-terrane map of Idaho (wp), western Idaho suture line; Virginia Piedmont and Blue Ridge; Geologic Terranes of Eastern New York and Connecticut; neUS; Ordovician Mid-Atlantic prior to Taconic collision, and Taconic collision, (wp); Geologic terrane map of Precambrian Basement Rocks (pdf) in Wisconsin, Minnesota and Iowa, and Geologic map of Precambrian Basement Rocks (pdf); Penokean Volcanic Terrane; Late Mesozoic and Early Cenozoic terrane translation along western North America: The Baja-BC hypothesis (wp); maps: non-NA: Australia; New Zealand terranes; Scotland; Mozambique; suture and other major shear zones associated with terrane amalgamation in the Arabian-Nubian shield showing estimates of the ages of convergence (wp); major geologic terranes of Taiwan and the faults that separate them (wp); Mongolian terrane map;

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