Mendenhall Research Fellowship Program

20-32. Informing assessments of critical minerals using stable isotopes


Closing Date: January 6, 2022

This Research Opportunity will be filled depending on the availability of funds. All application materials must be submitted through USAJobs by 11:59 pm, US Eastern Standard Time, on the closing date.

How to Apply

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The Department of Interior presently considers 35 minerals (or materials) to be critical, meaning that they are essential to U.S. economic or national security and have supply chains that are vulnerable to disruption (83 FR23295). These are aluminum, antimony, arsenic, barite, beryllium, bismuth, cesium, chromium, cobalt, fluorspar, gallium, germanium, graphite, hafnium, helium, indium, lithium, magnesium, manganese, niobium, platinum group metals, potash, rare earth elements, rhenium, rubidium, scandium, strontium, tantalum, tellurium, tin, titanium, tungsten, uranium, vanadium, and zirconium. Assessments of known and undiscovered resources of these minerals are based on models of deposit types in which they occur. Several important models are incomplete due to knowledge gaps in the understanding of deposit genesis. There is an urgent need to fill these gaps so that the U.S. Geological Survey can perform mandated assessments with the highest possible degree of accuracy.

This Research Opportunity is based in a stable isotope laboratory within the Geology, Geophysics and Geochemistry Science Center, located in Denver, Colorado, that has been a center for mineral resources research since the 1960s. The opportunity is intended to further the geologic understanding of critical mineral ore-forming systems by applying stable isotope methods to significant unresolved genetic questions. A variety of critical mineral occurrences and deposit types are available for study. Possible field sites include multiple locations in Alaska and locations in northern Wyoming, western Utah, southern Nevada, and southern Illinois. Proposals to study other deposits or occurrences are welcome provided the research objectives significantly advance the geologic understanding of critical mineral resources. A wide variety of ore genesis questions are amenable to scientific investigation using stable isotope methods, including questions pertaining to sources of hydrothermal fluids, sources of ore constituents, and thermal and redox properties of ore forming environments. Deposit types relevant to this opportunity range considerably in geologic occurrence, from plutonic to volcanic to high pressure-temperature metamorphic to low temperature sedimentary.

Geologic models of critical mineral deposits are of active interest in the broader economic geology research community. They relate to several focus areas described in the most recent U.S. Geological Survey Science Strategy document (U.S. Geological Survey, 2021). They are also directly relevant to mandates contained in the Energy Act of 2020 because they are essential to domestic and global assessments of undiscovered resources of critical minerals.

Interested applicants are strongly encouraged to contact the Research Advisor(s) early in the application process to discuss project ideas.


U.S. Geological Survey, 2021, U.S. Geological Survey 21st-Century Science Strategy 2020–2030: U.S. Geological Survey Circular 1476, 20 p.,

Proposed Duty Station: Lakewood, Colorado

Areas of PhD: Geology, chemistry, or related fields (candidates holding a Ph.D. in other disciplines, but with extensive knowledge and skills relevant to the Research Opportunity may be considered).

Qualifications: Applicants must meet the qualifications for one of the following: Research Geologist or Research Chemist.

(This type of research is performed by those who have backgrounds for the occupations stated above.  However, other titles may be applicable depending on the applicant's background, education, and research proposal. The final classification of the position will be made by the Human Resources specialist.)

Human Resources Office Contact: Sinar Santillano Oliveros, 303-236-9585,

Apply Here


Craig A Johnson, Ph.D.

Research Geologist
Geology, Geophysics, and Geochemistry Science Center
Phone: 303-236-7935

Douglas C Kreiner

Research Economic Geologist
Alaska Science Center
Phone: 907-786-7190

George Case

Research Economic Geologist
Alaska Science Center
Phone: 907-786-7472

Allen Andersen, PhD

Research Geologist
Geology, Minerals, Energy, and Geophysics Science Center
Phone: 509-368-3115

Albert H Hofstra

Research Geologist
Geology, Geophysics, and Geochemistry Science Center
Phone: 303-236-5530