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U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

**Giant porphyry-related metal camps of the world --- a database**

by Felix E. Mutschler1, Steve Ludington2, and Arthur A. Bookstrom3

1999

OPEN-FILE REPORT 99-XXXX

U.S. DEPARTMENT OF THE INTERIOR

BRUCE BABBITT, Secretary

This report is preliminary and has not been reviewed for conformity with
U.S. Geological Survey editorial standards or with the North American
Stratigraphic Code. Any use of trade, firm, or product names is for
descriptive purposes only and does not imply endorsement by the U.S.
Government.

1Eastern Washington University, Cheney, WA

2U.S. Geological Survey, Menlo Park, CA

3U.S. Geological Survey, Spokane, WA

**Introduction**

Porphyry-related metal deposits are large-tonnage, generally low-grade,
hydrothermal deposits related to igneous intrusions emplaced at high
crustal levels. Mineralization may be confined to pluton-hosted
disseminations, stockworks, vein sets, and breccias and (or) occur in
skarns, replacements, veins, and disseminated deposits peripheral to the
inferred source pluton. Coeval epithermal precious metal-dominated
deposits may occur above, or be telescoped onto, porphyry systems. This
spectrum of deposit types includes many of the world\'s largest
accumulations of Cu, Mo, Au, Ag, Sn, and W. As such the deposits
represent critical economic resources and important exploration targets
(Gilmour et al., 1995; Kirkham and Sinclair, 1996; Singer, 1995).

To prospect efficiently for undiscovered mineral deposits, or to
speculate about future metal supply, it is useful to define the size,
distribution, and geologic characteristics of known deposits. It is to
that end that we have compiled this database, the release of which is
part of a larger effort to characterize the world\'s largest and most
important porphyry-related deposits. We hope that this compilation can
be of aid to researchers, explorationists, and students alike. We also
recognize that any compilation effort is, by its very nature,
incomplete, as well as out-of-date as soon as it is released. Thus, we
welcome any corrections or updates to the data presented here and
request that you direct any communications to Felix Mutschler
(fmutschler@mail.ewu.edu, 509-359-2854) or Steve Ludington
(slud@usgs.gov, 650-329-5371).

**Definitions**

In this database, the geographic unit used for reporting data is a
\"camp.\" A camp may include one or more \"mining districts\"
established by law or defined by literature usage. Further, a camp may
include one or more \"mineral deposits\" representing a single \"deposit
type\" (see below), or several genetically related deposit types, in
close enough proximity to be exploited with a common infrastructure and
administrative unit. We recognize that in some cases we may have
included some genetically or temporally unrelated deposits in a camp,
and any inferences we make are subject to this caveat. A \"giant camp\"
has a gross metal endowment exceeding one or more of the threshold
values described below.

Terms such as \"giant\" and \"world-class\", as applied to mineral
deposits, have been defined in many ways. See, for example, Singer
(1995) and Laznicka (1999). For this database, we chose the following
metal endowments (production + reserves + resources at the lowest
reported cutoff values) as thresholds: Cu, 1,000,000 mt; Mo, 250,000 mt;
Au, 155,000 kg (ca. 5,000,000 troy oz); Ag, 7,750,000 kg (ca.
250,000,000 troy oz); Sn, 200,000 mt; W, 100,000 mt; Pb, 1,000,000 mt;
and Zn, 1,000,000 mt. These values are generally similar to those used
by Singer (1995) to define giant or world-class deposits, and to those
used by Laznicka (1999) to define large accumulations.

These thresholds were chosen to represent large deposits, with
potentially long mine lives, and that would be of potential interest to
major mining companies. Using the thresholds as a guide, we compiled
information for 234 mining camps worldwide that meet one or more of
these thresholds. In addition, the database contains 49 further deposits
that were included because some have metal endowments closely
approaching giant status, some represent extensions of metallogenic
provinces that contain giant deposits, and some provide important data
useful for defining giant deposit types.

**Deposit descriptions and classification**

To provide capsule descriptions of the porphyry-related deposits in the
database, we have adopted a tri-partite classification nomenclature
based on deposit type, metal commodities, and source/host pluton
chemistry.

**Deposit type**

Porphyry deposits consist of stockwork, disseminated, and breccia-hosted
mineralization that is restricted to plutons and their immediate wall
rocks. Examples of porphyry copper deposits are El Salvador, Chile, and
Bingham, Utah. Examples of porphyry molybdenum deposits are Climax,
Colorado, and Buckingham, Nevada. An example of a porphyry
tungsten-molybdenum deposit is Logtung, Yukon. Examples of plutonic
porphyry gold deposits include Fort Knox and Pogo, Alaska, which are
more deeply emplaced than subvolcanic porphyry gold deposits, like
Refugio, Chile.

Greisen deposits consist of stockwork, vein, pipe, and breccia-hosted
greisen mineralization (ore minerals + quartz, muscovite, topaz,
fluorite) in or near the roof of a granite pluton. An example of a
greisen tin deposit is Pitinga, Brazil. Kara-Oba, Kazakhstan, is a
greisen tungsten-molybdenum deposit.

Skarn deposits consist of pyrometasomatic and contact metasomatic
mineralization, typically hosted by carbonate-rich rocks in close
proximity to a pluton. The Nambija district, Ecuador, is an example of a
skarn gold deposit. Mactung, Yukon, is a skarn tungsten deposit.

Epithermal deposits are high-crustal level vein, stockwork, breccia
pipe, and hot-spring deposits, primarily of precious metals. Some of
them occur above or peripheral to porphyry metal systems (Hedenquist and
others, 1996). They are commonly divided into high-sulfidation types
(the most common around porphyry systems), such as El Indio, Chile, and
Goldfield, Nevada, and low-sulfidation types, such as Cripple Creek,
Colorado, and the Emperor mine in Fiji.

Mesothermal manto deposits are fault zone-hosted veins and stratabound,
or breccia-hosted replacement, iron oxide-copper sulfide deposits. Their
origin is debated, but may be related to both apatite-bearing magnetite
deposits and porphyry copper deposits. In this database, we restrict the
designation to copper sulfide and hematite-rich deposits according to
the usage of Espinoza R. and others, 1996; Marschik and Fontboté, 1996;
and Vila and others, 1996, who describe these deposits in Chile. We
specifically exclude polymetallic base and precious metal
carbonate-hosted deposits that are often referred to as manto deposits
in North America. Those deposits are here classified as polymetallic
replacement deposits and are defined below. Examples of mesothermal
manto deposits include Mantos Blancos, Chile, and the Superior-Magma
mine, Arizona.

Replacement and vein deposits consist of hydrothermal polymetallic,
conformable to crosscutting, replacement bodies (blankets, lenses,
pipes, and chimneys) in carbonate rocks, and fissure veins in
non-reactive rocks. Examples include the polymetallic replacement
deposits at Bisbee, Arizona, and Tintic, Utah, and the vein deposits at
Butte, Montana.

Bolivian-type polymetallic vein deposits are veins, stockworks, and
sheeted vein complexes hosted by subvolcanic dacite intrusions and
characterized by significant endowments of tin and (often) silver
(Ludington and others, 1992). Largely restricted to the central Andes,
this class includes the porphyry tin deposits of Sillitoe and others
(1975). Examples include Cerro Rico de Potosí and Llallagua, Bolivia.
Kori Kollo, Bolivia, is a gold-rich example.

**Metal commodities**

To standardize the listing of metal commodities for porphyry-related
metal camps, we adopted the following conventions. Where different
tonnages of ore and (or) metals are reported for the same camp, we
follow Cox and Singer (1986), and use the largest tonnages reported, or
the tonnages associated with the lowest cutoff grades. In the deposit
descriptions, metals are listed in decreasing order of their
contribution to the total value of the camp\'s estimated endowment;
metals contributing more than 10 percent of the value are listed first,
with multiple metals separated by hyphens; metals contributing less than
10 percent, but more than 1 percent of the value are listed next, in
parentheses, followed by metals (in italics) which are reported to be
present, but for which no numeric values are available. Some examples of
these conventions, used in deposit descriptions in the database are: San
Manuel-Kalamazoo, Arizona - Porphyry Cu (Mo,Au,Ag), and Climax,
Colorado - Porphyry Mo (Sn,W).

**Source/host pluton chemistry**

Source/host pluton chemistry is also compiled in the database. Because
of differing rock nomenclature used in the literature by various
authors, we have, whenever possible, based our characterization of rock
chemistry on standardized rock names applied to major element analyses
of rocks from the mining camps. We have classified the camps
petrochemically into the following groups: C-A (calc-alkaline); which
may be subdivided into: GRD (granodiorite to low-silica granite), HSR
(high-silica rhyolite/granite), and PDC (strongly peraluminous dacite);
ALK (alkaline); and TRN (transitional, which includes substantial
amounts of coeval mixed alkaline and calc-alkaline rocks). Where the
designation is followed by an asterisk, we have compiled rock chemical
data to support the designation; otherwise we have depended on
descriptions in the literature.

**References cited**

Cox, D.P., and Singer, D.A., eds., 1986, Mineral deposit models: U.S.
Geological Survey Bulletin 1693, 379 p.

Espinoza R., S., Véliz G., H., Esquivel L., J., Arias F., J., and Moraga
B., A., 1996, The cupriferous province of the Coastal Range, northern
Chile, in Camus, F., Sillitoe, R.H., and Petersen, R., eds., Andean
copper deposits: new discoveries, mineralization, styles and
metallogeny: Society of Economic Geologists Special Publication 5, p.
19-32.

Gilmour, Paul, Andrew, R.L., Bernstein, Merwin, Maxwell, Ian, and
Morrissey, C.J., 1995, Porphyry copper deposits: history, recent
developments, exploration, economics, in Pierce, F.W., and Bolm, J.G.,
eds., Porphyry copper deposits of the American Cordillera: Tucson,
Arizona Geological Society Digest 20, p. 128-155.

Hedenquist, J. W., Izawa, E., Arribas, A., and White, N.C., 1996,
Epithermal gold deposits-Styles, characteristics, and exploration:
Resource Geology Special Publication Number 1, Society of Resource
Geology, Japan, 17 p.

Kirkham, R.V., and Sinclair, W.D., 1996, Porphyry copper, gold,
molybdenum, tungsten, tin, silver, in Eckstrand, O.R., Sinclair, W.D.,
and Thorpe, R.I., eds., Geology of Canadian mineral deposit types:
Geological Survey of Canada, Geology of Canada no. 8, p. 421-446.

Laznicka, Peter, 1999, Quantitative relationships among giant deposits
of metals: Economic Geology, v. 94, p. 455-474.

Ludington, Steve, Orris, G.J., Cox, D.P., and Asher-Bolinder, Sigrid,
1992, Mineral deposit models, in Geology and Mineral Resources of the
Altiplano and Cordillera Occidental, Bolivia, with a section on
Application of Economic Evaluations to Deposit Models, by Donald I.
Bleiwas and Robert G. Christiansen, U.S. Bureau of Mines: U.S.
Geological Survey Bulletin 1975, p. 63-89.

Marschik, Robert, and Fontboté, Luis, 1996, Copper (-iron)
mineralization and superposition of alteration events in the Punta del
Cobre belt, northern Chile, in Camus, F., Sillitoe, R.H., and Petersen,
R., eds., Andean copper deposits: new discoveries, mineralization,
styles and metallogeny: Society of Economic Geologists Special
Publication no. 5, p. 171-189.

Sillitoe, R.H., Halls, C., and Grant, J.N., 1975, Porphyry tin deposits
in Bolivia: Economic Geology, v. 70, p. 913-927.

Singer, D.A., 1995, World class base and precious metal deposits -A
quantitative analysis: Economic Geology, v. 90, p. 88-104.

Vila, Tomás, Lindsay, Nicholas, and Zamora, Richard, 1996, Geology of
the Manto Verde copper deposit, northern Chile: a specularite-rich,
hydrothermal-tectonic breccia related to the Atacama fault zone, in
Camus, F., Sillitoe, R.H., and Petersen, R., eds., Andean copper
deposits: new discoveries, mineralization, styles and metallogeny:
Society of Economic Geologists Special Publication no. 5, p. 157-170.

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CLICK HERE to receive the WORLD_PPY file via FTP

CLICK HERE to receive the INTRO file via FTP

CLICK HERE to receive the BIB file via FTP

CLICK HERE to receive the README file via FTP