Khalil Droubi

Omar Khalil Droubi

Tectonics~Precambrian Geology~Metamorphic Petrology

My research explores the evolving relationship between tectonics and mineral deposits from the Precambrian to the modern. I integrate field and petrologic observations with detailed microanalysis, geochemistry, and geochronology using EPMA, LA-ICP-MS, RAMAN, and SIMS instrumentation. I use these data to reconstruct continental tectonic histories from the Archean to the present and to shed insight on the pressure-temperature-fluid conditions for economic mineralization in convergent margins.

Currently, I am completing a PhD in Geoscience with a distributed PhD minor in data science at the University of Wisconsin-Madison working with Dr. Chloë Bonamici. Prior to that, I worked as a research assistant at Penn State University with Dr. Andrew Smye, completed an M.Sc in Geoscience (2022) at the University of Wisconsin-Madison while co-advised by Dr. Chloë Bonamici and Dr. Annie Bauer, and completed a B.Sc. in Earth Science with a minor in Spatial Science (2020) at the University of California-Santa Barbara where I conducted a Senior Honors thesis advised by Dr. Roberta Rudnick.

Please look around my website and email me at droubi [at] wisc [dot] edu if you have any questions and/or would like to collaborate.

Research

Some of my research projects are described below:

Outcrop photograph of kyanite quartzite in southwestern CA

Tectonic and metasomatic models for the Laramide Orogeny

In an NSF-funded collaboration with Northern Arizona University, one of my PhD chapters investigates rocks in southwestern USA with evidence for fluid-driven metamorphism during the Laramide Orogeny. By constraining the P-T-t conditions and fluid sources of metasomatism, I seek to improve upon existing geodynamic models for the Laramide Orogeny, as well as mineralization models for the region.

Outcrop photograph of pegmatite wall zone with pink elbaite (rubellite; Li-rich tourmaline) in northern WI.

Tectonic history of lithium-rich pegmatite formation

One of my PhD chapters is focused on constraining the timing, tectonic setting, and source of lithium-rich pegmatite deposits in northern Wisconsin. Northern Wisconsin offers a superb natural laboratory to explore the relationship between Precambrian tectonism, fluid-mediated metamorphism, and critical mineral formation.

Subset figure from manuscript in review depicting final stage of Penokean Orogeny.

Precambrian orogenies in the Upper Peninsula, MI, USA

I am actively interested in building high-resolution P-T-t paths for the Precambrian orogenies in the Upper Peninsula, Michigan and northern Wisconsin. Past research (currently in review at Precambrian Research) focused on improving temporal constraints with titanite and apatite petrochronology in one of the gneiss domes.

I use context from textural and chemical microanalysis to inform U-Pb age interpretations from LA-ICP-MS data.

Application of titanite petrochronology to Archean gneisses

My MS research focused on the first application of titanite and apatite petrochronology to two Archean gneiss localities: the Watersmeet gneiss dome in Michigan and the Acasta Gneiss Complex in Canada. The data generated by this project greatly informed our understanding of the tectonothermal record in these areas.

Subset figure from published paper depicting the potential of certain cations to substitute into titanite or apatite.

Development of titanite and apatite petrochronology

I am actively interested in accessory phase petrochronology (the combination of in situ geochronology and chemical microanalysis). I engage in the development of a wide variety of techniques aimed at measuring trace elements and isotopes in accessory phases. My collaborators and I have a published paper evaluating some of the existing titanite and apatite reference materials and techniques relevant to petrochronology.

Figure from published paper showing Lu zoning in garnet from a Mexican lower crustal xenolith.

Chemical microanalysis and petrochronology of xenoliths to constrain thermal state of the deep crust

One of my research interests, and the subject of past projects, is using xenoliths to constrain the past and present thermal state of the crust. I first fell in love with xenoliths as an undergraduate research assistant helping Dr. Roberta Rudnick and Dr. Francisco Apen with lab and field work on xenoliths from Tanzania, Siberia, Montana, and Madagascar (the subject of my Senior Honors Thesis). This was followed by research at Penn State that resulted in a published paper on crustal xenoliths from Mexico!

Preliminary forecast of funding allocated toward grants with "volcanic eruptions" as a key term in abstract.

Using natural language processing to communicate and forecast trends in the Earth Sciences

As a passionate Python data scientist, one of my interests is the subject of natural language processing (NLP), a machine learning technology that gives computers the ability to interpret, manipulate, and comprehend human language. Currently, I am exploring the application of NLP to the public-facing National Science Foundation awards database, through optimizing communication of funded research in a public website, testing trend forecasting applications, and exploring collaboration networks.

Publications and Theses

Droubi, O. K., Cipar, J. H., Smye, A. J., & Garber, J. M. (2024). Xenolith petrochronology (San Luis Potosi, Mexico) constrains heat sources for Cenozoic ultrahigh‐temperature metamorphism in the lower crust. Journal of Geophysical Research: Solid Earth, 129(8), e2024JB029138.

Droubi, O. K., Bauer, A. M., Bonamici, C., Nachlas, W. O., Tappa, M. J., Garber, J. M., & Reimink, J. R. (2023). U‐Th‐Pb and trace element evaluation of existing titanite and apatite LA‐ICP‐MS reference materials and determination of 208Pb/232Th‐206Pb/238U date discordance in Archaean accessory phases. Geostandards and Geoanalytical Research, 47(2), 337-369.

Droubi, O. K. (2022) Multiphase Petrochronology of Archean Gneiss Complexes: Unraveling polymetamorphic records at the Acasta Gneiss Complex, Northwest Territories, Canada and the Watersmeet Gneiss Dome, MI, USA (Master’s thesis, University of Wisconsin-Madison)

Droubi, O. K. (2020). Origins and evolution of the lower crust beneath central Madagascar: Insights from granulite-facies xenoliths in rift basalts (Undergraduate Senior Honors thesis, University of California-Santa Barbara) [available upon request]