Extraction of Chlorine in Sand Samples in the Canadian Rockies
Himani Yadav joined the Schoenbohm Lab as a PhD student in 2022 after completing her BSc, MSc and M. Tech degrees in India.
Her PhD research focuses on understanding the landscape evolution of the Southern Canadian Rocky Mountains that were formed ~80 million years ago and have been extensively reshaped by river and glacial erosion since then. With the aim to quantify the rate of change of this landscape, Himani's project is measuring the average erosion rates of various rivers across the Rockies by using cosmogenic isotopes that are produced by nuclear interactions of minerals with cosmic radiations.
When minerals are exposed to cosmic radiation, they accumulate varying amounts of isotopes based on the duration of exposure and depth. In Himani's case, she is measuring the concentration of Chlorine-36 (36Cl) that is known to be produced by cosmic radiation exposure in rocks and sediments, and it is the depth of the river that is highly relevant. As the production of the isotopes decreases with depth, it is the surface dependency that is crucial to infer information about the landscape. For example, in a slowly eroding landscape (vice versa for fast erosion), a sand grain will spend more time in the production window and will therefore have higher concentrations of cosmogenic isotope. To this end, she collected 22 river sand samples during two field seasons, which were later used for the extraction of 36Cl as part of her visit in Switzerland.
The processing of river sand to extract 36Cl isotopic concentrations was done in collaboration with Prof. Naki Akcar at the Surface Exposure Dating Laboratory at the Department of Earth Sciences, University of Bern, which required two separate visits: in November-December 2024 and January-February 2025. The funds provided by the CPS Research Visit Fellowship, with the support from the Vice Dean, Graduate’s Office, helped cover some of the travel costs between Toronto and Switzerland. Himani is grateful for the opportunity to participate in this research visit fellowship as the visits were essential for her PhD completion.
The chemical processing had two stages: 1) 36Cl separation from river sand - done at Surface Exposure Dating Laboratory, Department of Earth Sciences, University of Bern; b) 36Cl measurement - performed at the Accelerator Mass Spectrometer facility at Department of Physics, ETH Zurich, Switzerland.
During the visit, Himani greatly benefited from Prof. Akcar's one-on-one training for the isotope extraction method that is extremely relevant for her discipline. She also learnt other essential laboratory skills such as exercising lab safety protocols, working carefully with high concentration and lethal acids, chemical disposal procedures, and working in a dark room. Moreover, she also got an opportunity to interact with global researchers which fostered adaptability, flexibility, and exposure to new research perspectives - all of which are essential to enrich her graduate research experience.
The overall visit experience enhanced Himani's appreciation for UTM's and CPS' support programs such as travel funds, mental health and wellness resources, interdisciplinary colloquium talks, summer socials among other great initiatives. She feels motivated to be more participative and involved in departmental activities and she is happy to give back to her community by sharing her knowledge and experiences with incoming graduate students in the department.
