Geology and Geological Engineering

Dr. Gokce Ustunisik
Experimental Petrology and Planetary Geochemistry:
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Dr. Gokce Ustunisik

Ph.D. (2009), University of Cincinnati
Assistant Professor
Geology and Geological Engineering
South Dakota School of Mines
Rapid City, SD 57701

Research Associate
Earth and Planetary Sciences
American Museum of Natural History(AMNH)
New York, NY 10024

Research synopsis

I am experimental petrologist and high-temperature geochemist who focuses on the processes that determine planetary chemistry and the use of this chemical information, especially the volatile elements, to understand the origin and crustal evolution of planetary bodies.

Planetary Petrology and Cosmochemistry: In this area I focus on evaluating and quantifying the processes that changes the planetary chemistry. In effect, I try to ask how we can use the behavior of specific elements (Cl, F, S, C, H, OH) to understand the origin and evolution of planetary bodies. I work on a wide range of problems related to the high temperature crustal evolution of Moon, Mars, and other small planetary bodies such as chondrules and Ca-Al-rich inclusions (CAIs) and the role of volatiles and fluids on this. The approaches that I use range from analytical studies of Martian, lunar, and primitive meteorites to experimental simulation of a variety of magmatic processes. The specific areas that I conducted planetary research include degassing of lunar magmas, phase equilibria studies on the role of volatiles in changing mineral/melt equilibria in Martian magmas, and magmatic fluid/wall rock interaction in the Martian crust. Some recent highlights include the flash melting experiments implemented as time-series studies on synthetic chondrule compositions to explore the behavior of halogens in the volatilization of alkalis during chondrule forming processes and Cl, F apatite-melt partitioning experiments at low pressures which are fundamental to the use of apatite in assessing volatile abundances of planetary interiors, especially the Moon and Mars. My experiences in planetary geology has convinced me that many of the approaches used exclusively either in planetary or terrestrial petrology could profitably be transferred between fields. With the many recent successful NASA missions, much can be done to make a quantum leap forward in our knowledge of the formation and evolution of planetary bodies.

Petrology and Volcanology of Arc Magmas: I am interested in quantification of processes that control magma evolution at the depth (evolution of mantle chemistry) as well as in shallow plumbing systems (formation and differentiation of continental crust) underlying active stratovolcanoes. My focus is sorting out the geochemical signals that are imposed by various differentiation processes (e.g. crystallization, decompression/degassing, magma mixing/recharge, filter pressing, density-driven convection) and evaluate their relative roles and timing in different magmatic systems.
Some of the questions that I ask are:
1. What causes the magma diversity on continental crust in arc magmas?
2. What is the role of volatiles and fluids in this diversity by:
a) controlling the chemical evaluation of silicate melts and
b) generation of ore deposits through late-stage hydrothermal and mineralization processes?
3. How do vast archives of information recorded by minerals help to understands hazards of subduction zones such as volcanic eruptions and earthquakes?

Petrology of Mid-Ocean Ridge System: The largest geologic system on the Earth?s surface is the mid-ocean ridge igneous system. The forces that drive that system drives essentially all surficial processes on earth, from volcanoes, to plate tectonics and earthquakes to (through orogenesis) climate and geomorphology. My interests lie in understanding how heat and mass are transported in the mid ocean ridge system through study of phase equilibria and trace element behavior. This research involves analysis of natural samples, including major and trace element analyses of both melt inclusions and their host phenocrysts and well as numerical modeling of their behavior.

Big Data Petrology: As the lead PI on the LEPR (Library of Experimental Phase relationships) and traceDs components of the IEDA (Interdisciplinary Earth Data Alliance) initiative, I am working with my IEDA collaborators on developing a data system that will collect and provide access to all the available experimental data in experimental petrology. To date, we have compiled data from over 15,000 experiments and are in the process of developing an interface that will provide investigators access to information that was previously distributed across over 700 different publications - all in formats that differed from one another. Our goal is to provide a coherent source of shared information that will enable future research to begin at a shared starting point.

  • NSF OCE Marine Geochemistry and Geophysics (2017-2018)
    IEDA 2016-2021: Operation of a Multi-Disciplinary Data Facility for the Earth Science Community, Step-1Institutional PI on Collaborative research with Columbia University, Lamont Doherty Earth Observatory(LDEO).

  • NSF OCE Marine Geochemistry and Geophysics (2018-2019)
    IEDA 2016-2021: Operation of a Multi-Disciplinary Data Facility for the Earth Science Community-Step 2 Institutional PI Collaborative research with Columbia University, Lamont Doherty Earth Observatory (LDEO).

Chondrule heating/flash melting:Experiments simulating alkali (Na, K) volatilization during chondrule formation.

Chassigny meteorite:Provides evidence for: ponding at the base of the Martian crust, high pressures; dissolved magmatic volatiles (Cl, F, OH) from analysis of apatite; and fluid migration and water loss .

Low pressure degassing:Experiments simulating differential degassing of H2O, Cl, F, and S and their effects on lunar apatite volatile abundances.

Constraints from High-Pressure Experiments: Phase equilibria experiments on anorthitic megacrysts and their melt inclusions in plagioclase ultraphyric basalts (PUBs).

Temperature and Time Constraints on Dissolution and Fe-Mg Exchange between Relict Forsterite and Chondrule Melt: Implications for Thermal History of Chondrules.

contact: Dept. of Geology and Geological Engineering, 501 E. Saint Joseph St., SDSMT, Rapid City, SD 57701
phone: (605)394-2461 / fax: (605)394-6703 / email: