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Joshua M Rosera, Ph.D.

Joshua Rosera is a Research Geologist (Mendenhall Postdoctoral Fellow) with the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.

I am geologist interested in applying spatial analysis, high-precision geochronology, and radiogenic isotopic measurements to test models about the origins of mineral deposits and continental magma systems. My postdoctoral research at the USGS is focused on integrating large spatial datasets into tools that can be used to better explore, visualize, and model data related to mineral deposits. This includes developing multivariate tools that can analyze previously underutilized qualitative data attributes in historical mineral deposit datasets, as well as developing machine learning models for mineral prospectivity mapping.

I completed my M.S. and Ph.D. at the University of North Carolina, where I studied temporal and spatial relationships between caldera-forming silicic magma systems and mineral deposits. My collaborators and I use high-precision U/Pb zircon geochronology to better resolve timescales of magmatism related to mineralization, and where and when these events occur with respect to caldera formation. I am also interested in studying the origins of fluorine enrichment that is observed in numerous magma systems in the Southern Rocky Mountain region. We test hypotheses regarding how these systems achieve high fluorine abundances by analyzing deep crustal xenoliths, and by tracking the sources of fluorine-rich melts with radiogenic isotopes.

Prior to starting my Ph.D., I worked for Chevron as a mine and petroleum geologists. I worked at the Questa molybdenum mine in northern New Mexico up until its final closure in 2014. I spent the next two years in west Texas as an operations geologists where I assisted technical work for a mature waterflood.


  • Ph.D., Geological Sciences, University of North Carolina at Chapel Hill (2020)
  • M.S., Geological Sciences, University of North Carolina at Chapel Hill (2012)
  • B.S., Geology and Geography, University of Wisconsin – Oshkosh (2010)

Work Experience

  • Mendenhall Postdoctoral Fellow, U.S. Geological Survey (2020-present)
  • Graduate Research Consultant, University of North Carolina (2017; 2018)
  • Instructor, University of North Carolina (2016)
  • Research and Teaching Assistant, University of North Carolina (2010-2012; 2016-2020)
  • Earth Scientist, Chevron North America Exploration and Production Company (2014-2016)
  • Mine Geologist, Chevron Mining Inc. (2012-2014)
  • Research and Teaching Assistant, University of Wisconsin – Oshkosh (2008 – 2010)
  • GIS Intern, University of Wisconsin – Oshkosh (2010)
  • GIS Intern, City of De Pere, Wisconsin (2009)

Professional Affiliations

  • Society of Economic Geologists
  • Geological Society of America
  • Sigma Xi
  • American Geophysical Union

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