Department of Earth and Planetary Sciences


Geochemistry

Chemical, thermodynamic, and kinetic characterization of geologic materials in high- and low-temperature systems, using radiogenic and stable isotopes, organic geochemistry, experimental mineralogy, and elemental analysis. Some examples of current research by our faculty in Geochemistry are shown below. Visit the faculty members’ pages through the above links to get more information about research in Geochemistry at UT.

Meteorite analysisCosmochemistry

Hap McSween is involved with on-going studies of the chemistry of Martian rocks and soils, as determined by the APXS instrument on the Mars Exploration Rovers and by the Gamma-Ray Spectrometer on the Mars Odyssey orbiter, as well as from Martian meteorites.  The figure below is taken from a recent Science paper summarizing these data.  He has also been investigating how ratios of elements that can be analyzed with the Gamma-Ray and Neutron Detector on the Dawn spacecraft can be used to identify various kinds of HED meteorites.  This information will be critical in interpreting GRaND spectra from the Dawn mission to asteroid Vesta.  Dr. McSween is also involved in studies of the chemical compositions of chondritic meteorites.

Mineral Alteration

Dr. Labotka, in collaboration with Dr. D. Cole, Oak Ridge National Laboratory, has been studying experimentally the combined cation exchange of K and Na and the isotope exchange of O18 and O16 in alkali feldspar to determine the mechanism of mineral alteration. The image at left shows both the O-isotope–exchanged (nanoSIMS ion image) and K-exchanged (EMP x-ray image) rim on a grain of Amelia albite. The feldspar was reacted with a 2 m KCl solution, in which the solvent was H2O18.

Images

sill sillWhole-rock and Isotope Geochemistry;
P-T Conditions in Metamorphic Rocks

Bob Hatcher studies the geochemistry of major, minor, trace, and rare-earth elements in metamorphosed basalts and granitic rocks to provide clues about the tectonic environments in which they formed.  Using the USGS-Stanford Sensitive High-Resolution Ion Microprobe (SHRIMP) instrument, he is able to determine  the U-Pb ages of complex zircons from granitic and unmetamorphosed to metamorphosed sedimentary rocks.  In addition, Bob employs various thermometers on the UTK electron microprobe to determine the P-T conditions of metamorphism also entails.

 



 

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