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

superterrane. And (8) in the Canadian Cordillera, continuing on from the late Early Cretaceous were the Bayonne (BA), Cassiar
(CA), Selwyn (SW), and Whitehorse (WH) belts, which contain granitic-magmatism-related deposits, and are hosted in or near
anatectic granitic plutons of the Omineca-Selwyn plutonic belt which is interpreted as forming during final accretion of
Wrangellia superterrane to North American continental margin. In the below descriptions of metallogenic belts, a few of the
noteable or signficant lode deposits (table 4) are described for each belt.
---
168' 156' ,A; t.32 UTE CRmwEaw
Arct~c
m - w
Ocean 0 a-CMw
6b w--&wm ' -0-
WH-whwmm
#LIIZ-WnrrgdlyaJ.lr
m-Wra--w
0 800
1680 I
Figure 80. Generalized map of major Late Cretaceous metallogenic belts, overlap assemblages, and tectonically-linked subduction-
zone or accretionary-wedge terranes for Alaska, Canadian Cordillera, and adjacent offshore areas. Refer to text for description of
metallogenic belts. Adapted from Nokleberg and others (1997b, 1998). Refer to figure 60 for explanation.
Metallogenic-Tectonic Model for Early
Late Cretaceous (100 to 84 Ma; Figure 81)
During the early Late Cretaceous (Cenomanian though Santonian - 100 to 84 Ma), the major metallogenic-tectonic events
were (fig. 81; table 3): (1) establishment of a series of continental-margin arcs and associated metallogenic belts, and companion
subduction-zone assemblages almost continuously around the Circum-North Pacific; (2) continued opening of an ocean which
would become the Amerasia, Canada, and Eurasia Basins; (3) completion of accretion of the Wrangellia superterrane and
formation of associated metallogenic belts; and (4) in the eastern part of the Circum-North Pacific, a change to orthogonal
compression between the Farallon Ocean plate and North America.
Specific Events for Early Late Cretaceous
(1) At about 32" to 60" paleolatitude, the Olyutorka island arc commenced activity. Parts of the arc are preserved in the
Nemuro (NE), Kronotskiy (KRO), and Olyutorka-Kamchatka (OKA), Iruneisky (IR), Shmidt (SHT), and Terpeniya (TR) terranes.
Forming in the Olyutorka arc were the Koryak Highlands metallogenic belt, which contains zoned mafic-ultramafic PGE and Cu
massive sulfide deposits, and the Vatyn (VT) metallogenic belt, which contains volcanogenic Mn and Fe deposits. Also associated
with the arc was subduction of part of adjacent oceanic plate to form the Vetlovskiy (VT) terrane. This arc and companion
subduction zone migrated northward toward the Okhotsk-Chukotka continental-margin arc.