Determining Grain Deformation in a Thin Section

Author: Olivia Wylie | Major: Geology and Physics | Semester: Spring 2024

My name is Olivia Wyllie. I just finished my junior year at UArk, and am a part of the J.

William Fulbright College of Arts and Sciences. I am a double major, majoring in Geology and

Physics. My mentor is Dr. Dumond, and he is a part of a geosciences department.

The goal of my research is to constrain mechanisms of formation and evolution of the

lower continental crust; a subject that is highly debated among geologists. There is a consensus

that to begin formation of the lower crust, melts of the mantle must rise to the boundary between

the crust and the mantle. Beyond this, how the crust forms and evolves is still considered a

mystery. To address this, my research involves analyzing mainly grains of garnet, but also

clinopyroxene and hornblende, in thin sections from the Athabasca granulite terrain. The terrain

is a part of the Canadian Shield where the lower continental crust is exposed at the surface, with

minimal deformation.

This semester, I’ve looked for evidence of strain and ultra-high temperature (UHT) metamorphism in the

garnet, clinopyroxene, and hornblende in my samples, which indicates a rock is from the lower continental crust.

I’ve selected a handful of thin sections with the clearest indicators, and on my trip to the terrain this summer,

I’ll sample the areas where those thin sections were collected. Further sampling will allow me to send samples for bulk

geochemical analysis and isotopic dating, and the data I’ll receive from those procedures will

allow me to geophysically model lower crustal conditions. From this modeling and the

aforementioned data, I’ll be able to determine what processes occured as the lower crust formed

and developed.I’ve always been interested in tectonics and crustal development, so when I was looking

for a research mentor, I specifically looked for professors whose work was relating to those

topics. I noticed through UArk’s website that one of my previous professors, Dr. Dumond, was

researching formation and evolution of the continental crust. He had previously taught my

structural geology class; which I enjoyed greatly. I reached out through email, and he sent me his

proposal and scheduled a meeting for us to discuss the project. I found it fascinating, and soon

after began my research under him.

The biggest challenge I’ve faced as an undergraduate researcher is balancing research and

classes. I didn’t have time to be in my mentor’s lab as often as I wanted, and it could be hard to

find the motivation after a long day of classes to get myself to the lab. The best thing for me to

counter this was coming up with a schedule that I worked out with my mentor for what day and

time I was going to be in the lab each week. Having a schedule I could follow helped me get

motivated and prevented me from procrastinating in my research.

I’m very grateful to have had this research opportunity, and can’t wait for my trip this

summer and to resume my research next fall.