USGS Professional Paper 1697 - Alaska Resources Library
USGS Professional Paper 1697 - Alaska Resources Library
USGS Professional Paper 1697 - Alaska Resources Library
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138 Metallogenesis and Tectonics of the Russian Far East, <strong>Alaska</strong>, and the Canadian Cordillera<br />
Northeast, (4) initiation of subduction of the North American<br />
Continental Margin under the Angayucham subduction-zone<br />
terrane, (5) continuation of opening of the Amerasia, Canada,<br />
and Eurasia Basins in response to sea-floor spreading in the<br />
Arctic Ocean, (6) the beginning of accretion of the Wrangellia<br />
superterrane in the Southern Canadian Cordillera, and (7)<br />
around the Circum-North Pacific, continued sinstral transpression<br />
between oceanic plates and continents.<br />
Specific Events for Early Cretaceous<br />
(1) Far to the south at about 32º paleolatitude, the<br />
Mainitskiy island arc (Mainitskiy terrane, MAI) commenced<br />
activity. Forming in the arc were the Tamvatney-Mainits<br />
(TAM) belt, which contains podiform Cr deposits hosted in<br />
zoned mafic-ultramafic plutons, and the Mainits (MA) belt,<br />
which contains kuroko massive sulfide deposits. Tectonically<br />
linked to the arc was the Alkatvaam accretionary-wedge terrane<br />
(AV), which formed from subduction of part of the adja-<br />
168<br />
168<br />
al<br />
156<br />
Arctic<br />
Ocean<br />
CG<br />
144<br />
PW<br />
132<br />
56<br />
52<br />
72<br />
NAC<br />
co<br />
yk<br />
oc<br />
KY<br />
ia<br />
K<br />
yk<br />
km<br />
K<br />
km<br />
at<br />
at<br />
kw<br />
kw<br />
at<br />
wr<br />
72<br />
oa<br />
FO<br />
co<br />
FR<br />
oa<br />
SBRoa<br />
om kn<br />
TI<br />
TS<br />
om SW<br />
om<br />
oa<br />
NO<br />
bs<br />
bs<br />
om<br />
KO<br />
ECAcn<br />
KA<br />
kh<br />
om<br />
oa<br />
ECAom DE<br />
BR<br />
CG<br />
gg<br />
WHTE<br />
cn<br />
TI<br />
CA<br />
om<br />
cr<br />
WSE<br />
FO<br />
NR<br />
PI<br />
sk<br />
bo<br />
bs<br />
km<br />
KY<br />
DE<br />
oa<br />
PW<br />
AL<br />
CG<br />
YAK<br />
gg cr<br />
cn<br />
NY<br />
GD<br />
TG<br />
oa PW<br />
QC<br />
CG<br />
PAC<br />
BR<br />
AL<br />
CO<br />
Pacific<br />
Ocean<br />
156 144<br />
cent oceanic plate. This arc and companion subduction zone<br />
migrated northward toward the Kony-Murgal island arc.<br />
(2) The Umlekan arc (Umlekan-Ogodzhin volcanic-plutonic<br />
belt (uo) and associated units) continued activity. Associated with<br />
this belt was subduction of part of the ancestral Pacific oceanic<br />
plate to form the Amur (AM) and Badzhal (BD) terranes.<br />
(3) In the same region, the accretion of the Bureya (BU)<br />
superterrane against the Ulban accretionary-wedge terrane<br />
(UL) was completed along the Mongol-Okhotsk suture (MO),<br />
thereby closing the Mongol-Okhotsk ocean. Forming during<br />
accretion was the Stanovoy (ST) metallogenic belt, which<br />
contains anatectic, granitic-magmatism-related deposits, and<br />
the Selemdzha-Kerbi (SK) metallogenic belt, which contains<br />
Au-quartz vein deposits. In the same region is the Kondyor<br />
(KO) metallogenic belt, which contains zoned mafic-ultramafic<br />
Cr-PGE deposits and is hosted in zoned mafic-ultramafic<br />
intrusions intruding Stanovoy block of the North Asian<br />
Craton. Also in the same region is the Algama (AL) metallogenic<br />
belt, which contains stratiform Zr deposits These two<br />
48<br />
0<br />
64<br />
tt<br />
CB<br />
kl<br />
cn<br />
oa<br />
cr<br />
NAC<br />
132<br />
EARLY CRETACEOUS<br />
METALLOGENIC BELTS<br />
BA - Bayonne<br />
CA - Cassiar<br />
CB - Caribou<br />
ECA - East-Central <strong>Alaska</strong><br />
FR - Fish River<br />
NO - Nome<br />
TS - Tombstone<br />
SBR - Southern Brooks Range<br />
SW - Selwyn<br />
WH - Whitehorse<br />
WSE - Western-Southeastern <strong>Alaska</strong><br />
ns<br />
FS gg gg PA<br />
gg<br />
oa<br />
cr<br />
BR ns<br />
sb<br />
PR<br />
HO<br />
OC<br />
JFR<br />
56<br />
JF<br />
SZ<br />
BA kl<br />
cn<br />
WA<br />
CC<br />
cr<br />
cn<br />
ca<br />
800 km<br />
om<br />
ca<br />
oa<br />
0 800 mi<br />
Figure 62. Generalized map of major Early Cretaceous metallogenic belts and overlap assemblages for <strong>Alaska</strong>, Canadian Cordillera,<br />
and adjacent offshore areas. Refer to text for description of metallogenic belts. Adapted from Nokleberg and others (1997b, 1998).<br />
ns<br />
FO<br />
48
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