People

Faculty

Professor Jay Banner (banner@jsg.utexas.edu) – Fred M. Bullard Professorship in Geological Sciences; Distinguished Teaching Professor; Clean Lab PI and TIMS Lab Co-PI

Website

Banner’s research and teaching interests center on Earth surface processes with the goal of understanding the interactions that occur between the atmosphere-land-ocean systems, and how these interactions are preserved in the geologic record. Avenues of investigation include the origin and evolution of carbonate rocks, groundwater, surface water, and the oceans. These subjects are explored using a range of approaches that include field studies, petrography, isotope and trace element geochemistry, geochronology, and modeling. Examples of research projects using these approaches are studies of cave deposits as records of the links between climate change and hydrology, studies of carbonate rocks as records of the chemistry of ancient oceans, and studies of modern aquifers in urbanizing environments.


Professor John Lassiter
(lassiter1@jsg.utexas.edu) – Leonidas T. Barrow Centennial Chair in Mineral Resources; Peter T. Flawn Centennial Chair in Geology; Clean Lab PI and TIMS Lab Co-PI

Website

Dr. Lassiter’s research focus is on the application of isotope and trace element geochemistry to fundamental problems of the Earth’s origin and evolution, including but not limited to: Structure and chemical evolution of the mantle and crust; Origin of mantle plumes and nature of plume/lithosphere interaction; Generation and segregation of magma; Origin and chemical evolution of continental lithosphere; Chemical fluxes in constructive and destructive tectonic environments. Current areas of interest include the role of crust and lithospheric mantle recycling in the generation of mantle chemical heterogeneity, the origin and distribution of water and other volatile elements in the Earth’s interior, and the thermal and chemical evolution of the Earth’s core and core/mantle boundary.

Managers

Dr. Aaron Satkoski (satkoski@jsg.utexas.edu) – TIMS Lab Manager

As lab manager Aaron maintains a functioning clean lab and thermal ionization mass spectrometer.  He works with faculty, researchers and students to help them process samples through the lab and obtain publishable data.

His research focuses on the developing new analytical techniques using the TIMS and MC-ICP-MS.  As well, he also works to unravel the history of the early Earth by examining the initiation of plate tectonics; crust formation and evolution; isotopic evolution of seawater as it relates to redox and crustal weathering through time.

 

 

Dr. Staci Loewy (sloewy@jsg.utexas.edu) – MC-ICP-MS Lab Manager

As laboratory manager, Staci maintains the MC-ICP-MS lab and clean labs. Aaron and I work with UT faculty, students, and visitors to acquire publishable data to achieve their research needs. We develop new analytical techniques as needed, train users to conduct their own research, and complete analyses for contract work.

Staci’s new research focuses on developing analytical methods using multiple high sensitivity Daly detectors in the Nu Plasma 3D multi-collector ICP mass spectrometer and on adapting U-Th dating techniques, commonly used in carbonate rocks, to date ostrich egg shells found in archeological sites. Staci’s on-going research focuses on crustal evolution and supercontinent reconstruction. Staci’s interests are not linked to a particular isotope system or period of geologic time. She seeks collaborations where I may employ my isotope expertise to address an interesting problem and then employ whichever methods are necessary to answer the questions.

 

Students

Daniel Villanueva – PhD Student –

Daniel’s interested in understanding the offset in isotopic compositions between MORB (more radiogenic) and abyssal peridotites (less radiogenic), especially observed in the Os and Hf systems. If MORB are partial melts from the residual abyssal peridotites, this unexpected isotopic difference may be due to a radiogenic component in the source of MORB.  In addition, Os and Pb isotopic heterogeneity in peridotites has also been documented to scales as small as a hand sample, where interstitial sulfide grains are more radiogenic than included sulfides.  Through the Os and Pb isotopic study of single-grain sulfides in both MORB and abyssal peridotites, coupled with other isotopic systems in silicates of peridotites and MORB glass, he will be able to evaluate what the nature of the radiogenic component(s) is for both MORB and peridotites and if it is a common component for both rock types.

The results will be important to better understand both MORB petrogenesis and the composition of the upper mantle.

 

 

Evan Ramos – PhD Candidate –

Evan’s research focuses on fluid-rock interactions in the crust and its consequences for the geologic carbon cycle. A central objective of his PhD research is to refine our understanding of Li isotopes, from modern to geologic timescales, as a means to more effectively probe silicate weathering and other Earth surface processes. His research often combines field work, analytical geochemistry (O, C, Li isotopes of water and sediments), and numerical modeling to solve these problems.

 

 

 

George Segee-Wright – PhD Student –

George’s research focuses are the recycling of volatile elements from the lithosphere into the mantle and the distribution of volatiles in the mantle. He is currently working to determine the fate of halogens that are subducted past the volcanic front by measuring the halogen content of subduction-modified subcontinental mantle xenoliths. Additionally, he is interested in measuring the volatile content of ocean island basalts to better constrain the volatile content of various mantle reservoirs.