USGS Professional Paper 1697 - Alaska Resources Library

metallogenic belts are interpreted as forming during plutonic
intrusion related to continental-margin transform faults when
the margin of the North Asian Craton was being deformed during
collision and accretion of outboard terranes.
(4) The continental-margin Uda arc (Uda volcanicplutonic
belt, ud, and Uda-Zeya Sedimentary Basin, uz)
continued to form. Associated with the arc was subduction
and sinistral transpression of the final remnant of the Mongol-Okhotsk
oceanic plate, thereby forming the Ulban (UL)
terrane. Sinistral transpression continued along the Mongol-
Okhotsk suture (MO).
(5) The extensive Kony-Murgal continental-margin and
island arc and Pekulney island arc continued to form. Associated
with these arcs was subduction of part of the ancestral
Pacific oceanic plate to form the Talovskiy (TL), Penzhina-
Anadyr (PA), and Pekulney (PK) terranes.
(6) Behind the Kony-Murgal arc, the Kolyma-Omolon
superterrane (KLO) was accreted between at about 140 to 100
Ma. During the early stage of accretion, the Main collisional
granite belt (ma; 144 to 134 Ma) formed (Layer and others,
1995; Fujita and others, 1997). At about the final stage of
accretion, the subduction-related Northern granite belt (no)
oa
Overlap assemblages (Cretaceous and
Cenozoic), and undivided terranes
OVERLAPPING MIDDLE AND LATE TERTIARY MAGMATIC
ARCS; EMPLACED ACROSS ALL MAJOR TERRANES
al Aleutian; ca Cascade; ia Interior Alaska;
wr Wrangell; yk Yukon-Kanuti
Middle and late Tertiary back-arc units
bs Bering Strait; cb Columbia River Basalt
OVERLAPPING EARLY TERTIARY MAGMATIC ARCS
EMPLACCED ACROSS ALL MAJOR TERRANES
at Alaska Range-Talkeetna Mountains;
cn Coast-North Cascade; ia Interior Alaska;
km Kuskokwim Mountains
OVERLAPPING MIDDLE JURASSIC AND EARLY CRETACEOUS
MAGMATIC ARCS; EMPLACED ACROSS CC, KO, QN, NAM, ST
ns Nelson; sb Spences Bridge;
sk Skeena; tt Tahtsa-Three Sisters
EMPLACED ACROSS WRANGELLIA SUPERTERRANE
gg Gravina-Nutzotin-Gambier; kh Kahiltna
JURASSIC AND CRETACEOUS ARC TERRANES
KY Kyokuk; NY Nyac; TG
Togiak
JURASSIC, CRETACEOUS, AND EARLY TERTIARY
ACCRETIONARY-WEDGE AND
SUBDUCTION-ZONE TERRANES
BR Bridge River (youngest part);
CG Chugach; GD Goodnews; HO Hoh;
OC Olympic Core; PR Pacific Rim;
PW Prince William; SZ Siletzia; YA Yakutat
Figure 62.—Continued,
Early Cretaceous Metallogenic Belts (144 to 120 Ma; figs. 61, 62) 139
EXPLANATION
formed at about 127 to 120 Ma (Fujita and others, 1997). In
contrast to the Main granite belt, the coeval Northern granite
belt is interpreted as forming in response to subduction related
to closure of an inlet of the South Anyui Ocean. As a result,
the northern bend of the Kolyma-Omolon structural loop
formed (Sengor and Natal’in, 1996a). As a continuation of
the structural loop, the extensional Transverse granite belt (tr)
formed (Parfenov, 1995c). Associated with accretion of the
Kolyma-Omolon superterrane (KLO) and intrusion of anatectic
granites were formation of the Allakh-Yun (AY), Darpir
(DP), Kular (KU), Shamanikha (SH), Tompon (TO), Verkhoyansk
(VK), Yana-Kolyma (YA), and Yana-Polousnen (YP)
metallogenic belts, which contain a large suite of Au quartz
vein and granitic-magmatism-related deposits.
(7) The Oloy island arc and the opposing Nutesyn and
Koyukuk island arcs continued to be active on the opposite
sides of the South Anyui and Angayucham Oceans. Forming in
the Oloy arc were the Oloy (OL) and Left Omolon (LO) metallogenic
belts, which contain granitic-magmatism-related deposits.
Parts of the Oloy, Nutesyn, and Koyukuk island arcs are
preserved in the Nutesyn (NU), Koyukuk (KY), Togiak (TG),
and Nyac (NY) terranes. Associated with these arcs was sub-
AL
BR
CC
CO
DE
FO
FS
KO
PA
QC
TI
WA
om
NAC
CLASTIC SEDIMENTARY BASINS
(Jurassic, J; Cretaceous, K; and Tertiary, T)
co Colville (KT); bo Bowser (JK);
kn Kandik River (JK); kw Kuskokwim (KT);
K (undifferentiated)
FAULT NAMES
METALLOGENIC BELTS
ECA
CRATON
NAC North American Craton
CONTACTS AND FAULTS
Contact
Active subduction zone;
Cretaceous thrust faults
Pre-mid-Cretaceous thrust faults
Major mid-Cretaceous and younger
strike-slip transform faults
Aleutian megathrust
Border Ranges thrust fault
Cascadia megathrust
Contact thrust fault
Denali strike-slip fault
Foreland fold and thrust system
Fraser-Straight Creek strike-slip fault
Kobuk-South Fork strike-slip fault
Pasayten strike-slip fault
Queen Charlotte-Fairweather dextral
transform fault
Tintina strike-slip fault
Waneta thrust fault
GRANITE BELTS
Omineca-Selwyn collisional granite belt
OCEANIC UNITS
JF Juan de Fuca; PAC
Pacific
JFR Juan de Fuca oceanic ridge