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

Proterozoic ophiolite, island-arc, and passive continental-margin terranes which were displaced along dextral-slip faults along the
margin of the
KK - Ketchrkan
UB - M l a y a
Figure 33. Pennsylvanian (320 to 286 Ma) stage of metallogenic-tectonic model. Refer to text for explanation of metallogenic-
tectonic events, to tables 3 and 4 for descriptions metallogenic belts and significant deposits, and to figure 18 for explanation of
abbreviations, symbols, and patterns. Adapted from Nokleberg and others (1997b, 1998, 2000).
North Asian Craton (NSC) and North Asian Craton Margin (NSV, KN) (Zonenshain and others, 1990; Vemikovsky and others,
1998).
(5) Fragments of the North American Craton Margin (NAM), including the Yukon-Tanana (YT) and Kootenay (KO)
terranes, which formed offshore during Early Mississippian rifting, occurred offshore from the North American Craton Margin
(NAM). Towards the North American Craton Margin were the Slide Mountain and Seventymile Oceans. An extensive but thin
submarine fan was deposited in the Slide Mountain Ocean (Anvil Ocean of Templeman-Kluit, 1979) between the Yukon-Tanana
(YT) and Kootenay (KO) continental-margin terranes and the North American Craton Margin (NAM).
(6) At an unknown location, the Skolai island arc was active along the length of the Wrangellia superterrane (WRA).
Associated with the arc was a presumed (unknown) subduction zone (UNK). The Skolai arc deposits consist mainly of Early to
Middle Pennsylvanian plutons and Pennsylvanian and Permian marine volcanic and volcaniclastic rocks that are interpreted as
forming at high latitudes (Nokleberg and others, 1994b, 2000). Forming with the arc was the Alaska Range-Wrangell Mountains
(ARW) metallogenic belt which contains granitic-magmatism-related deposits and the Ketchikan (KK) metallogenic belt which
contains kuroko massive sulfide deposits. The basement for the Skolai arc may in part be the Alexander terrane which contains a
fragment of an early and middle Paleozoic continental-margin arc (Nokleberg and others, 1994b). Insufficient data exist to
ascertain the relative positions of the Wrangellia superterrane (WRA; and contained Skolai arc), and its associated subduction
zone, with respect to the Stikinia and Quesnellia island-arc terranes and their associated subduction zones. Fauna in the Slana Spur
and Eagle Creek (former Mankornrnen) Formations of the eastem Alaska Range indicate a high-latitude environment (Petocz,
1970).
(7) Subsequently in the Permian, the major part of the Stikinia-Quesnellia arc overlapped part of the Yukon-Tanana
terrane after weak initiation of the arc in the Mississippian. This arc, defined by Permian granitic plutons in the Yukon-Tanana