Volcanic and sedimentary strata of the Late Cretaceous MacColl Ridge Formation were sampled and demagnetized to reevaluate the paleomagnetically derived paleolatitude of the allochthonous Wrangellia terrane. This belt extends from the Wrangellia Terrane in Alaska to the Chilliwack group of Canada. The observed variability in the crust across the Alaska Range suture zone is likely controlled by the differing compositions of the terranes On the basis of Triassic stratigraphy (Jones et al., 1977) and paleomagnetism (Hillhouse, 1977), the name Wrangellia was proposed for large areas of outcrop in Alaska, British Columbia, and Oregon (Fig. The vast Wrangellia terrane of Alaska and British Columbia is an accreted oceanic plateau with Triassic strata that contain a 3- to 6-kilometers thick flood basalt, bounded above and below by marine sedimentary rocks. The concept of "orders of relief" refers to: the classification of landscapes based on scale. E: Blocks and faults rotate, causing down-corners to become basins and up-corners to become mountains or ridges. Examples include the Sturgeon Lake camp in the Archean Wabigoon terrane of Ontario (Morton et al., 1990; Whalen et al., 2004) and the Devonian Buttle Lake VMS camp in the Wrangellia Terrane of British Columbia (Barrett and Sherlock, 1996a). Mesozoic strata of the northwestern Talkeetna Mountains are located in a regional suture zone between the allochthonous Wrangellia composite terrane and the former Mesozoic continental margin of North America (i.e., the Yukon-Tanana terrane). Alexander terrane, forming the Wrangellia composite terrane, which then accreted to the western margin of North America (W ang et al., 1988; P lafker et al., 1989; Ridgeway et al., 2002; Trop et al., 2005). Wrangellia formed as a sequence of island arcs and oceanic plateaus with coral reefs, starting late in the Paleozoic era. As the vice was closed between Wrangellia and terranes to the east, the rocks in the vice were squeezed downwards and upwards, metamorphosed and uplifted. The Pacific Rim and Crescent Terranes make up the western part of Vancouver Island, and their accretion is responsible for the folding and uplift of Cretaceous Nanaimo Group rocks (Figures 21.5.1 to 21.5.3). Porphyry deposits are intrusion-related, large tonnage low grade mineral deposits with metal assemblages that may include all or some of copper, molybdenum, gold and silver. Major faults in Alaska and parts of Yukon and BC are shown with purple lines. The map is derived from (Wilson et al., 1998; Israel, 2004; Massey et al., 2005a, b; Wilson et al., 2005; Brew, 2007, written comm. The Carnian Stuttgart-Formation (Schilfsandstein) of the Central European Basin contains relics of Triassic volcanic detritus in form of euhedral zircon grains and … D: Only small amounts of extension occur with nonrotating fault blocks. Allochthonous terranes, suspect terranes, exotic terranes.. WRANGELLIA was one of the first described and probably the most widely known of the North American Cordilleran terranes. B) continental shield, or craton. Numerous terranes exist in Alaska. Figure 2: Map showing the distribution of Wrangellia flood basalts in Alaska, Yukon, and British Columbia. Initial values range from +1.0 to + 7.3 and initial ratios range from 0.70323 to 0.70481. Wrangellia extends along the Pacic margin of North America from southern Vancouver Island through ... R. Lein, A delayed carbonate factory breakdown during the Tethyan-wide Carnian Pluvial Episode along the Cimmerian terranes (Taurus, Turkey). Rocks of the Wrangellia Terrane (green) are found in several blocks that are exposed from Denali National Park in Alaska, through British Columbia and all the way into western Idaho. Quiz 12: Crustal Formation. These two terranes may be related but are considered to be exotic to North America 9. B)craton. Previous paleomagnetic studies of the Triassic volcanic rocks of Wrangellia in south-central Alaska and British Columbia have given paleolatitudes of 10°-17°, which are anomalously low in comparison to results from similar-aged rocks of nuclear North America. The Taku and Tracy Arm terranes may represent metamorphosed portions of one or more of the neighboring terranes or they may contain stratigraphic sections that are displaced relative to … Caught inside the tectonic wake of a migrating restraining bend," Jeff A. Benowitz and a … Alt Text Map showing the Klamaths terranes sitting on the Mesozoic and Tertiary sedimentary rock in southern Oregon and northern California; going from east to west starting with eastern klamath of the early paleozoic to jurassic periods, central metamorphic of the devonian period, western paleozoic and triassic … Why is the Wrangellia terrane considered to be part of the same terrane as the scattered in pieces from western Idaho northward to Alaska? B)a terrane in southern Tibet that migrated to the region during the Paleozoic from Australia. ranes, at least Wrangellia seems to have been transported to a more southerly paleolatitude west of the Laurentian margin (Aberhan, 1999; Smith et al., 2001). A tectonostratigraphic terrane is not necessarily an independent microplate in origin, since it may not contain the full thickness of the lithosphere. 1977, 1986). ... Wrangellia is the most well-know terrane in the Insular group. variety of Mesozoic and Paleozoic terranes that are situated between W rangeUia to the west and terranes of the North Cas cades to the east (Fig. These terranes were widely separated from each other, and also from Wrangellia, until the Late Jurassic: (1) the Haro terrane, an Upper Triassic arc-volcanic sequence; (2) the Turtleback terrane, a Paleozoic arc and Wrangellia terranes were emplaced against the Stikine terrane to the east. C) the inactive remains of ancient tectonic activity. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period … 1) (Wrangellia and Alexander terranes, Coast Plutonic Complex, North Coral faunas, here presented, show taxonomic affinity with coeval collections from other Cordilleran terranes, specifically the Wallowa terrane (northeastern Oregon and Idaho) and Peru (South America) as well as the distant Tethys region. ~Wrangellia composite (WCT) of P2019 western Kahiltna basin after P2019 Intermontane superterrane (IMS) and older accreted terranes. Wrangellia and the Alexander terrane are the two largest outboard terranes with characteristics that indicate a seemingly exotic nature with respect to the Laurentian margin ().The two terranes, along with smaller outboard terranes and the larger Peninsular terrane, comprise the Insular terranes and are separated from more inboard Intermontane terranes by Mesozoic and younger … the Stikine and Yukon^Tanana terranes prior to 110 Ma, and at present makes up the eastern portion of the CMB. A) a terrane in southern Tibet that migrated to the region during the Paleozoic from Australia. Many terranes were extensively sheared subsequent to their accretion, giving them highly elongated shapes. ALEXANDER-WRANGELLIA-PENINSULAR TERRANE The Alexander and Wrangellia terranes (Figure 1), originally defined by apparent differences in their Paleozoic to Late Triassic histories [Jones et al., 1•972, 1977], were adjacent to one another by Pennsylvanian time (308 _ 6 Ma) [Gardner et al., 1988]. Al-though the latitude of Wrangellia and its position relative to North We refer to the Wrangellia Terrane in Alaska and Yukon as Northern Wrangellia and areas in British Columbia as Southern Wrangellia. Wrangellia to other terranes, such as the Alexander terrane, have also recently been revised. In their recent publication, "Why is Denali (6,190 m) so big? The southern Coast Belt includes the Wrangellia terrane along the western edge and terranes of the Intermontane superterrane along the eastern margin and to the east ... Refer- 1,2,3 2,3 4 Methow basin UCretaceous L Cretaceous nonmarine red beds and andesites marine clastic rocks 5 5,6,7 Cadwallader terrane The Triassic to Lower Jurassic portion of the Wrangellia terrane is conformable and rests nonconformably on a thick succession of flood basalts in the Western Cordillera of North America (Greene et al., 2010). This belt extends from the Wrangellia Terrane in Alaska to the Chilliwack group of Canada. of terranes of the North American Cordillera is the Insular Superterrane which is composed of the Wrangellia and Alexander terranes. The areas of Wrangellia in Alaska and Yukon are referred to as Northern Wrangellia and areas in British Columbia are referred to as Southern Wrangellia. D)composite zone. To what larger parent might the orphaned Wallowa ter-rane belong? As described in Section 21.5, two additional terranes were accreted to the west coast during the Cenozoic. On the West coast of North America, the coast ranges and the coastal plain form the margin. a According to our data, the metavolcanic rocks of both the Wrangellia terrane and the Gravina assemblage are characterized by dominance of Pd over Pt as shown by mean Pd/Pt ratios of 2.30 and 1.61, respectively, for the lower and upper parts … Garver and Davidson hypothesized that Chugach lay alongside Wrangellia during the Late Cretaceous, yet it is now juxtaposed against the Peninsular terrane, having experienced even larger dextral displacements. The Wrangellia terranes refer to: a former volcanic island arc that migrated 10,000 km (6200 mi) to its present location along the western margin of North America. The Wrangellia composite terrane consists of Late Proterozoic and younger magmatic arc, oceanic plateau, lifted arc, and flysch belts (Plafl
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