Metallogenesis and Tectonics of the Russian Far East, Alaska, and ...

Figure 46. Lawyers Au-Ag epitiefmel vein deposit, Toodoggone Wllogenic belt, Canadian Cordillera. Schefnatic goologic map
showing various zones. Adapted from Vulimiri and others (1986).
Origin of and Tectonic Controb for
Toodoggone Metallogenic Bedt
The Toodoggone metallogenic belt is hosted in the Todoggone Formation, a Early Jurassic succession of subaerial,
intermediate, calc-alkaline to alkaline, predominantly pyroclastic rocks, and coeval and cornagmatic pluW afthe
Black Lake Suite which occur on the outer limb of the oroclinal warp of the Stikinia and QumUia idmd an: and miated
terranes. Tbe transition fiom alkaline to caloalkaIise magmatism is interpreted as forming during the final stages of the oroclinal
warp in the Early Jurassic, before accretion of the StiLinia.Quesnellia arc and associated Cache Creek subduction-zone ternme in
the Middle Jurassic (Mihalynuk and others, 1994; Monger and Nokleberg, 19%; Noklebwg and others, 2000). Tbe volcanic rocks
of the Hazelton Group and correlative units, such as the Toodoggone Formation, and associated granitaid plutonic rocks, represent
emergence of the arc and a transition from marine to subaerial deposition in the Early Jurassic. The Toodoggone Formation
consists exclusively of high-K, calc-alkaline volcanic rock which wae deposited in higb-anergy subeerial flows, associated air-fall
tuff, and lesser lava flows batween about MO Lo 190 Ma.
The Stikinia island-arc terrane is interpreted as forming on the &formed continental margin gtrata of Yukon-Tanana
terrane which may be a nftd hgmmt ofthe North American Craton Margin (Gebrels and otbers, 1990; Monger and Nokleberg,
1996; Noklcbexg and olbers, 1984c, 1997c, 2000). Several otbm metadlogenic belts are herein interpreted as f& during
granitic magmatisrn associated with formation of the Stikinia and Quemellia island arcs, including the Copper Mountain (Norbh),
Galore Creek, Guichon, Motassin, Texas Creek, md Toodoggone belts.
Coast Mountains Metallogenic Belt of Volcanogenk
Cu-ZnAu-Ag Massive Sulfide Deposits (Belt CM)
Northern British Cdumbia
The Coast Mountains metallogenic belt of volcanogenic massive sulfide deposits (fig. 42; tables 3,4) occurs in the
western limb of the oroclinally-warped Stikinia island-arc terranc. To the west, the belt and teme are border by, and in part,
intruded by plutons dong the eastern edge of the Coast Plutonic Canplex. The metallogenic belt contaim a variety of significant
kuroko, Cyprus, and Besshi massive sulfide deposits (Nokleberg and others, 1997a, b). The significant deposits are theTulsequah
Chief and Eskay Creek kuroko Zn-Cu-Pb-Au-Ag massive sulfide deposits, the Granduc Besshi massive sulfide deposit, and tbe
Alice Arm Silver and Anyox districts of Cyprus massive sulfi& deposits (table 4) (Nokleberg and ofhm 1997% b, 1998).