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22-13. Constraining the geologic and tectonic conditions of critical element mineralization in the Mojave Desert, California 

We are seeking a Mendenhall Fellow to apply geologic mapping, structural geology, geochronologic, and geochemical approaches to define the framework geology necessary to characterize critical mineral ore systems in the Mojave Desert.  

Description of the Research Opportunity

As defined in the Department of the Interior Secretarial Order 3359, Critical Mineral Independence and Security, the USGS is responsible for developing a plan to improve the Nation’s understanding of domestic critical mineral resources. In order to define and prioritize data acquisition and research, the Earth Mapping Resource Initiative (Earth MRI) has adopted a mineral systems approach, based on how ore deposits form in relation to their broader geologic and tectonic contexts (Hofstra and Kreiner, 2020). The Mojave Desert is host to significant critical mineral resources, particularly rare earth elements (REE) and lithium, which are required for clean energy and various technological applications. However, despite a significant body of geologic research in the region, there remain significant knowledge gaps related to the framework geology needed for a comprehensive understanding of its critical mineral systems.  

We seek a Mendenhall Fellow to apply geologic mapping, structural geology, geochronologic, and geochemical approaches to critical mineral ore systems in the Mojave Desert. Bounded by the San Andreas Fault system on the south and the Garlock Fault on the north, the Mojave Desert is crossed by many faults of the Eastern California Shear Zone that have poorly constrained slip rates and total offset. These faults dissect Precambrian through Miocene geologic units, some of which are also affected by older faults associated with tectonic events from Precambrian supercontinent assembly through the development of several batholiths and volcanic arcs, culminating with the modern Pacific-North American plate boundary system. Potential applicants are encouraged to think broadly and propose research activities that improve our understanding of the complex geologic framework of the region and how those factors combined to form critical mineral systems. Possible research objectives include, but are not limited to,  

  • Determining the geodynamic/tectonic regimes relevant to understanding formation of the Mountain Pass REE system, and potentially other prospective areas for REE mineralization in the Mojave Desert  

  • Delineating the sedimentary accumulation of lithium in the Barstow area, including the sources and depositional conditions, and diagenetic, hydrothermal, and/or brine processes that enrich them to ore-grade levels  

  • Definition of the time-temperature-pressure paths of igneous and metamorphic rocks pre- and post-Laramide to constrain the relationships between crustal structure, volcanism, and hydrothermal conditions relevant to critical mineral systems  

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



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): U.S. Geological Survey Open-File Report 2020–1042, 26 p.,  


Proposed Duty Station(s)

 Moffett Field, California

Spokane, Washington   


Areas of PhD

Geologic mapping, structural geology, economic geology, igneous petrology, metamorphic petrology, geochronology, thermochronology, or isotope geochemistry 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).  



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.)