USGS Professional Paper 1697 - Alaska Resources Library

format (Nokleberg and others, 1996) and in CD-ROM format
(Nokleberg and others, 1997a), (5) a GIS compilation of the
summary terrane map, mineral deposit maps, and metallogenic
belt maps of the Russian Far East, Alaska, and the Canadian
Cordillera (Nokleberg and others, 1998), (6) a study of the
Phanerozoic tectonic evolution of the Circum-North Pacific
(Nokleberg and others, 2000), and (7) a dynamic computer
model for the metallogenesis and tectonics of the Circum-
North Pacific (Scotese and others, 2001). These articles,
tables, and maps contain the full suite of mineral deposit data,
mineral deposit location maps, metallogenic belt maps, and
tectonic interpretations that are utilized in this study.
A complete listing of the project goals, and methods are
available on the Internet/Web at http://minerals.er.usgs.gov/
wr/projects/majdeps.pdf. Major recent articles for the project
(Nokleberg and others, 1993, 1994a, 1996, 1997a,b,c, 1998,
2000) are available on the Internet/Web at http://geopubs.
wr.usgs.gov/. This project was started at the invitation of the
Soviet Academy of Sciences to the U.S. Geological Survey in
1988. Subsequently, several organizations and many individuals
volunteered to work on various aspects of the project,
which has produced a large variety of articles and maps. Other
organizations participating in the project include the Russian
Academy of Sciences, Russian Ministry of Natural Resources
(former Ministry of Geology and ROSKOMNEDRA), Alaska
Division of Geological and Geophysical Surveys, Geological
Survey of Canada, Geological Survey of Japan, Exxon
Exploration Company, University of Alaska, and Michigan
State University.
This project represents a major joint attempt of a large
group of geologists from Russia, Alaska, and the Canadian Cordillera
to compile, synthesize, interpret, and publish major studies
on the mineral resources, metallogenesis, and tectonics of
this vast and geologically complicated region of the earth. The
project includes a number of geologists who have each gathered
field data and observations in their respective parts of the
Russian Far East, Alaska, and Canadian Cordillera over many
years and who have come together as a large international team
to compile and synthesis a vast amount of data for a large region
of the Earth. Other recent metallogenic synthesis of parts of the
Russian Far East, Alaska, and the Canadian Cordillera include
those by Dawson and others (1991), Sidorov and Eremin
(1994), Goncharov (1995a,b), Goryachev (1995, 2003), Nekrasov
(1995), Parfenov (1995d), Popeko (1995), Ratkin (1995),
Ratkin and Khanchuk (1995), Nokleberg and others (1984,
1987, 1988, 1993, 1994a,b, 1995a, 1996, 1997a,b), Sidorov and
Eremin (1995), Goldfarb (1997), Goldfarb and others (1997,
1998, 2000), and Young and others (1997). A volume containing
papers on the geology and mineral deposits of the Russian
Far East was edited by Bundtzen and others (1995). A volume
containing papers on the stratiform ore deposits in northeastern
Asia was edited Goryachev and Byalobzhesky (1996). A
volume containing papers on the mineral deposits of Alaska was
edited by Goldfarb and Miller (1997). A volume on the geology
of Mesozoic gold quartz veins in Northeastern Asia was published
by Goryachev (1998). A volume on the pre-Cretaceous
metallogeny of Northeastern Asia was published by Shpikerman
(1998). A volume containing papers on the Tintina Gold Belt in
Alaska and the Yukon-Territory, Canada, was edited by Tucker
and Smith (2000).
Metallogenic Belts
In this study, the regional metallogenesis of the Russian
Far East, Alaska, and the Canadian Cordillera is synthesized,
compiled, and interpreted in terms of metallogenic belts. This
synthesis and compilation is based on data for about 1,079 significant
lode deposits and 144 major metallogenic belts for the
region (Nokleberg and others 1997a,b, 1998). A key element
for this type of analysis is definition of metallogenic belt that
is defined on the basis of a geologic unit (area) which either
contains or is favorable for a group of coeval and genetically
related, significant lode mineral deposit types (defined in the
below section on definitions). A metallogenic belt may be of
irregular shape and variable size; the size is partly a function
of the scale of the analysis; in this study, metallogenic belts
were synthesized and compiled at a scale of 1:10,000,000
scale (Nokleberg and others 1997a,b, 1998). In this report for
each time span, metallogenic belts are described in a clockwise
geographic succession, according to similar tectonic
environments, around the Circum-North Pacific, from the Russian
Far East to Alaska to the Canadian Cordillera.
For definition and outline of metallogenic belts, the following
three criteria were used (Nokleberg and others, 1995a)
(1) Mineral Deposit Association—Each metallogenic belt
includes a single mineral deposit type or a group of coeval,
closely-located and genetically-related mineral deposits types
for the region, as listed in table 1. (2) Tectonic Event for Formation
of Mineral Deposits—Each belt includes a group mineral
deposits, which formed in a specific tectonic event (for
example, collision, accretion, rifting). (3) Favorable Geological
Environment—Because a metallogenic belt is underlain by
a geological host rock and (or) structure that is favorable for a
particular suite of mineral deposit types, a belt is predictive for
undiscovered deposits. Consequently, the synthesis and compilation
of metallogenic belts can be useful for mineral exploration,
land-use planning, and environmental studies.
In this study, a metallogenic belt is essentially synonymous
with the term mineral-resource tract as originally
defined by Pratt (1981) and used for assessment of mineral
resource potential in the United States, as exemplified in
Ludington and Cox (1996). The metallogenic belt maps and
underlying regional geologic (terrane and overlap assemblage)
maps constitute a basic part of the three-part methodology of
quantitative mineral resource assessment as described by Cox
(1993) and Singer (1993, 1994).
Methodology
Introduction 3
The methodology for the analysis of the complex metallogenic
and tectonic history of the Russian Far East, Alaska,