Porphyry Copper Deposits of the World: Database, Map, and Grade and Tonnage Models

Mineral deposit models are important in exploration planning and quantitative
resource assessments for two reasons: (1) grades and tonnages among deposit
types are significantly different, and (2) many types occur in different
geologic settings that can be identified from geologic maps. Mineral deposit
models are the keystone in combining the diverse geoscience information on
geology, mineral occurrences, geophysics, and geochemistry used in resource
assessments and mineral exploration. Too few thoroughly explored mineral
deposits are available in most local areas for reliable identification of the
important geoscience variables or for robust estimation of undiscovered
deposits-thus we need mineral-deposit models. Globally based deposit models
allow recognition of important features because the global models demonstrate
how common different features are. Well-designed and -constructed deposit
models allow geologists to know from observed geologic environments the
possible mineral deposit types that might exist, and allow economists to
determine the possible economic viability of these resources in the region.
Thus, mineral deposit models play the central role in transforming geoscience
information to a form useful to policy makers. The foundation of mineral
deposit models is information about known deposits-the purpose of this
publication is to make this kind of information available in digital form for
porphyry copper deposits.

This report is an update of an earlier publication about porphyry copper
deposits. In this report we have added 84 new porphyry copper deposits and
removed 12 deposits. In addition, some errors have been corrected and a number
of deposits have had some information, such as grades, tonnages, locations, or
ages revised.

This publication contains a computer file of information on porphyry copper
deposits from around the world. It also presents new grade and tonnage models
for porphyry copper deposits and for three subtypes of porphyry copper deposits
and a map showing the location of all deposits. The value of this information
and any derived analyses depends critically on the consistent manner of data
gathering. For this reason, we first discuss the rules used in this
compilation. Next, the fields of the data file are considered. Finally, we
provide new grade and tonnage models.

[Summary provided by the USGS.]