Nick Konovalchik '21

Research with Jeff Rahl, Summer 2019

This past summer, I was fortunate enough to spend part of the field season helping Dr. Jeff Rahl with his research on detrital zircon geochronology as well as paleostress analysis. I spent six weeks, two of which were in the field, working alongside Jeff and learning from him. His research explores the possibility of a past transcontinental drainage system as a mechanism for transporting sediment Westward from the Appalachian Mtns. The transcontinental drainage system was diverted by the uplift of the Ancestral Rocky Mtns about 325 ma, and the resulting basins began accumulating sediment. By studying the geochronology and thermochronology of the zircons and monazite present in these igneous and sedimentary rocks, we can make inferences about the provenance of these crystals. Through the grant that he received from the National Science Foundation, we were able to travel out to travel out West3 to do some field work and collect samples. We spent two weeks in the field, driving from W&L here in Lexington, VA to the Wichita Mtns. in OK, the Arbuckle Mtns. in OK, and the Sangre de Cristo Mtns. in NM.

We spent a lot of time on the road and hiking in the mountains equipped with a geologic map in search of specific rock formations to sample. We collected igneous bedrock from the mountains we visited, and sedimentary rocks from the surrounding basins for zircon and monazite dating. Back on campus for the remaining four weeks I worked with Jeff to help develop a method for separating zircon and monazite crystals. This would allow the crystals to be dated using U-Th/He decay, giving us the provenance. We also collected limestone samples to perform calcite twinning analysis on. I learned how to successfully measure a rock's strike and dip, a useful fieldskill and something that is crucial in paleostress analysis. Back at the lab, I used the wet saw to cut rock chips out of these samples so that they could be sent off to be cut into thin sections. We got to analyze some of these thin sections on the SEM using EBSD here at school. This experience introduced me to parts of the country that I have not yet had the opportunity to explore, and taught me valuable information/skills that will help me in my future in whatever field of geology I decide to go into. I especially enjoyed hiking Hermit's Peak in the Sangre de Cristo Mtns, which took us to an elevation of 10,000 feet with beautiful views of the New Mexican landscape.

Support provided by the Geology Department and the R. Preston Hawkins IV Geology Fund