The US Geological Survey (USGS) will invest more than $3.1 million to map critical mineral resources in Arizona in partnership with the Arizona Geological Survey. The funding comes in part from an investment by the Bipartisan Infrastructure Law in the USGS Mineral Resources Program’s Earth Mapping Resources Initiative (Earth MRI), which provides $320 million over five years through the USGS to advance scientific innovation and map critical minerals.

The USGS and the Arizona Geological Survey (AZGS) will collaborate on an airborne geophysical survey of the Arizona copper porphyry belt in southeast Arizona near the New Mexico border. The Arizona porphyry copper belt includes some of the world’s largest endowments of mineral resources such as copper and molybdenum.

The new high-resolution data will help define some potentially concealed mineral resources and complement geological and geochemical surveying efforts that the Arizona Geological Survey is undertaking.

The Arizona porphyry copper belt is one of the world’s greatest sources of copper and molybdenum, among other mineral commodities. Given that this survey directly abuts the New Mexico porphyry copper belt survey completed earlier in 2023, the two surveys will make a major contribution to understanding the mineral endowment of more than 20,000 square miles of highly prospective mineral terrane in the southwest US.

—USGS scientist Mark Bultman, who is leading the survey

A road map of southeastern Arizona with the survey area marked in a red polygon Sources/Usage: Public Domain.

The critical mineral commodities that are the focus of this survey are:

• Aluminum, used in almost all sectors of the economy

• Arsenic, used in semi-conductors

• Bismuth, used in medical and atomic research

• Gallium, used for integrated circuits and optical devices like LEDs

• Germanium, used for fiber optics and night vision applications

• Indium, used in liquid crystal display screens

• Lithium, used for rechargeable batteries

• Manganese, used in steelmaking and batteries

• Rare earth elements group, primarily used in magnets and catalysts

• Tellurium, used in solar cells, thermoelectric devices, and as alloying additive

• Tin, used as protective coatings and alloys for steel

• Tungsten, primarily used to make wear-resistant metals

• Zinc, primarily used in metallurgy to produce galvanized steel

The airborne survey will include the collection of magnetic and radiometric data. These different methods can be used to map rocks at the surface beneath trees and vegetation, and in some cases, several miles underground. Magnetic data, which image the deepest rocks, can be used to identify ancient faults, magma bodies and other geologic features, while radiometric data indicate relative amounts of potassium, uranium and thorium in shallow rocks and soil and can also be used to characterize mine waste.