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21-3. Precambrian tectonic influences on mineral systems and critical mineral resource potential of the United States


Closing Date: November 1, 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.

Please communicate with individual Research Advisor(s) on the right to discuss project ideas and answer specific questions about the Research Opportunity.

How to Apply


The core of the North American continent is underlain by a complex framework of Precambrian geologic terranes that have disparate histories and geologic environments of formation. The assembly of the continent’s cratonic core and its subsequent outward growth span at least three supercontinent cycles. Linkages between observed episodic ore deposit formation, subsequent preservation and the supercontinent cycle are well established (e.g., Pehrsson et al., 2015). The Precambrian rocks also record profound changes in global geodynamics, tectonic styles, and atmospheric and ocean chemistry, and Earth’s secular evolution directly influenced the formation and distribution of Precambrian mineral systems and associated ore deposits (e.g., Santosh and Groves, 2022). Mineral systems have been identified in many Precambrian terranes (e.g., marine chemocline, volcanogenic seafloor and mafic magmatic systems of Hofstra and Kreiner [2020]). Thus, the Precambrian cores of continents have demonstrated potential to host a diverse variety of mineral resources that include many commodities that are essential to the modern economy and have potential for supply chain disruptions (i.e., critical minerals). Furthermore, Precambrian terranes acted as sources that likely influenced the formation, distribution, and metallogenic signatures (especially critical minerals) of younger mineral deposits during Phanerozoic tectono-metamorphic, magmatic, and (or) erosion-depositional events. However, significant uncertainties remain in our understanding of the Precambrian basement framework of North America, particularly in vast regions of the United States that are covered by younger geologic deposits or were disrupted or significantly overprinted by younger tectonic events. Additionally, the metallogenic inventories and processes by which metals were concentrated, remobilized, and redistributed within and among Precambrian basement terranes are not completely understood.

Field-based investigations of Precambrian bedrock terranes where they are exposed produce critical insights into their geological characteristics, tectonic evolution, and metallogenic potential. These investigations ideally integrate systematic geologic mapping with modern analytical approaches that include petrology, geochemistry, and geochronology. The application of the mineral systems concepts (e.g., Hageman and others, 2016) provides a framework that links the geotectonic setting of Precambrian rocks with their potential for hosting base, precious, and critical mineral resources at multiple scales. High-quality geophysical surveys can directly inform mapping and interpretation of the bedrock geology and mineral systems across large regions, and they provide essential means of projecting observations and (or) identifying key features in areas that are covered or have discontinuous bedrock exposure. Geochemical and isotopic approaches can help elucidate the influence of older crust and potential for enhanced critical mineral enrichments in younger mineralized regions. The USGS Survey Earth Mapping Resources Initiative (Earth MRI) is generating an unprecedented amount of new geologic, geochemical, and geophysical data across the United States to improve our understanding and assessments of domestic critical mineral resources. The USGS Mineral Resources Program also supports projects investigating the relationship(s) between the bedrock geologic framework and critical mineral resources in multiple regions of the United States. Some of these projects focus directly on Precambrian bedrock terranes, and others are working to identify possible Precambrian influences on younger mineral systems, districts or deposits.

To augment and enhance one or more of these active research efforts, we seek a Mendenhall Fellow with experience in bedrock geologic mapping, regional tectonic synthesis, hard-rock petrology, geochemistry, and(or) economic geology. The Fellow will ideally investigate the Precambrian bedrock framework and mineral systems in one or more regions of the United States with an emphasis on processes or features that influenced critical mineral enrichments. Some possible topics that research proposals may address include the following:

  • Distribution and mineral resource potential of Archean and Proterozoic mineral systems
  • Distribution, three-dimensional geometry, and characteristics of Archean crust
  • Tectonic setting, evolution, and metallogeny of Proterozoic accretionary provinces
  • Geological and (or) geophysical expression of Precambrian terrane boundaries
  • Tectonic setting, geochemistry, and metallogenic framework of Precambrian basinal strata
  • Tectonic setting and petrogenesis of mineralized Precambrian magmatic systems (e.g., Mountain Pass, Midcontinent rift, Stillwater complex)
  • Precambrian influences on Phanerozoic tectono-magmatic provinces, mineral systems, and critical mineral deposits (e.g., Laramide porphyry belt)

Proposals may include relevant analytical approaches using USGS facilities, academic collaborators, and (or) contract laboratories. Fieldwork may be conducted in coordination with active USGS projects or State field-based research projects funded by Earth MRI. The Fellow will have access to multidisciplinary expertise and scientific facilities at the chosen duty station and will collaborate closely with scientists and relevant project staff at multiple science centers. The Fellow may also collaborate and coordinate with other USGS funding programs (e.g., National Cooperative Geological Mapping Program), and collaboration with other USGS, State, and university geoscientists is encouraged.

Interested applicants are strongly encouraged to contact one or more of the Research Advisors early in the application process to discuss project ideas.


Hagemann, S.G., Lisitsin, V.A., and Huston, D.L, 2016, Mineral system analysis: Quo vadis: Ore Geology Reviews, v. 76, p. 504-522.

Hofstra, A.H., and Kreiner, D.C., 2020, Systems-Deposits-Commodities-Critical Minerals Table for the Earth Mapping Resources Initiative (ver. 1.1, May 2021): USGS OFR 2020–1042, 26 p., doi: 10.3133/ofr20201042

Pehrsson, S.J., Eglington, B.M., Evans, DnA.D., Huston, D., and Reddy, S.M., 2015, Metallogeny and its link to orogenic style during the Nuna supercontinent cycle: Geological Society of London Special Publication 424, p. 83-94, doi: 10.1144/SP424.5

Santosh, M. and Groves, D.I., 2022, Global metallogeny in relation to secular evolution of the Earth and supercontinent cycles: Gondwana Research, v. 107, p. 395–422, doi: 10.1016/

Proposed Duty Station(s):  Anchorage, Alaska; Reston, Virginia; Denver, Colorado; or Spokane, Washington

Areas of PhD:  Geology, geochemistry, economic geology 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 one of the following qualifications:  Research Geologist.

(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:  Emanuel Williams, 303-236-0569,

Apply Here