Geochemistry and Tectonic Setting of the Ophiolitic Ingalls Complex, North Cascades, Washington: Implications for Correlations of Jurassic Cordilleran Ophiolites

Abstract

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Plutonism at different crustal levels: Insights from the ~5–40 km (paleodepth) North Cascades crustal section, Washington

“…The shallowest level of the crustal section is represented by the Jurassic Ingalls ophiolite complex. It consists of Early Jurassic within-plate basalts and a more voluminous Late Jurassic supra-subduction-zone ophiolite deformed in an oceanic fracture zone represented in part by steeply dipping serpentinitematrix mélange (Miller, 1985;Metzger et al, 2002;MacDonald et al, 2008). The ophiolite is dominated by ultramafic mantle tectonites, has a thin crustal mafic intrusive and volcanic section, and is overlain by mainly mudstone and chert (Miller, 1985;Miller and Mogk, 1987;MacDonald et al, 2008).…”

Peridotites from the Khoy Ophiolitic Complex, NW Iran: Evidence of mantle dynamics in a supra-subduction-zone context

“…the Izu-OgasawaraMariana fore-arc (Ishii et al, 1992), Mariana back-arc-basin (Ohara et al, 2002), South Sandwich arc-basin system (Pearce et al, 2000), Izu-Bonin-Mariana fore-arc (Parkinson and Pearce, 1998), Yarlung Zangbo ophiolites (Dubois-Coté et al, 2005), Ingalls ophiolitic complex (Metzger et al, 2002) and Oman ophiolites (Tamura and Arai, 2006), all of which suggest depleted residues after partial melting of the upper mantle such as type 1 and type 2 peridotites in the Eastern Khoy Ophiolitic Complex.…”

Fast strain rates during pluton emplacement: Magmatically folded leucocratic dikes in aureoles of the Mount Stuart Batholith, Washington, and the Tuolumne Intrusive Suite, California

“…1B), which has been interpreted to represent a Late Jurassic ophiolite complex (e.g., Southwick, 1974;Metzger et al 2002). The Ingalls complex includes peridotites, serpentinites, gabbros, and various metasedimentary rocks, which were juxtaposed along numerous Late Jurassic faults in or adjacent to a fracture zone within a large ocean or marginal basin (Miller and Mogk, 1987).…”