Ophiolites, the Sierra Nevada, “Cordilleria,” and Orogeny along the Pacific and Caribbean Margins of North and South America

Abstract

Ophiolites are major expressions of orogeny; they are dominantly oceanic crust and mantle emplaced by collision of a mantle-rooted thrust (subduction zone) with a continental margin or island arc. Ophiolite nappes thus represent remnants of lithospheric plates; their basal thrusts (fossil subduction zones) intrinsically cannot be balanced; their displacements are unknown but very large.

Paleomagnetism of the Mount Stuart batholith revisited again: What has been learned since 1972?

“…1) (Wrangellia and Alexander terranes, Coast Plutonic Complex, North Cascades); for a more detailed review of the relevant geology see Cowan and others (1997). Accretion of the Insular superterrane to the margin of North America may be middle-late Jurassic (for example, McClelland and others, 1992), to perhaps midCretaceous (for example, Moores, 1998). Post accretion translation of the Insular superterrane (regardless of the magnitude of this translation) was accomplished by motion along margin-parallel transform faults (Beck, 1976;Price and Charmichael, 1986;Hollister and Andronicos, 1997;McClelland and others, 2000;Umhoefer, 2000), driven by highly N-oblique (Kula plate) or slightly N-oblique (Farallon plate) convergence of offshore oceanic plates with the North American margin (see Debiche and others, 1987).…”

Geology, Mantle Tomography, and Inclination Corrected Paleogeographic Trajectories Support Westward Subduction During Cretaceous Orogenesis in the North American Cordillera

“…Over the years a few workers (Moores 1970;Mattauer et al 1983;Chamberlain and Lambert 1985;Lambert and Chamberlain 1988;Moores 1998) proposed alternative models involving collision of North America with various arcs above westward-dipping subduction zones but they failed to garner traction in the community. Some more recent models for Cordilleran development, created to better explain the overall development of the orogen, posit that the leading edge of North America was subducted to the west beneath an exotic ribbon continent during Cretaceous orogenesis (Johnston and Borel 2007;Johnston 2008;Hildebrand 2009Hildebrand , 2013.…”

Tectonics: 50 years after the Revolution

“…The fold and thrust belt is antithetic to a single subduction zone active during the orogeny (e.g., Dickinson, 2004;Ernst, 2005;Ducea, 2001). A countervailing view is that Cordilleran orogens are in fact collisional, just as with the intracratonic orogens (e.g., Chamberlain and Lambert, 1985;Hildebrand, 2013Hildebrand, , 2009Johnston, 2008;Lambert and Chamberlain, 1988;Mattauer et al, 1983;Moores et al, 2002;Moores, and Day, 1984;Moores, 1970Moores, , 1998, and that the foreland fold and thrust belt is synthetic (i.e., parallel) to the subduction direction of colliding island arcs or continental slivers (ribbon continents) that were emplaced along subduction zones dipping away from the continent. Large-scale orogen-parallel movements are also present (e.g., Hildebrand, 2013, and references therein).…”

“…Some of these arcs display an oceanic history of tens of millions of years. Analysis of zircons in continent-derived sediments suggests that the latter were derived from the other side of the North American continent, or even Africa or Baltica (e.g., Moores, 1998;Moores et al, 2002;Wright and Wyld, 2006). The assembly of Asia was a long, complex amalgamation of separate continental blocks and island arcs Natal'in, 1996a, 1996b).…”