Ryan Owen Sigat

My research focuses on the applications of low- to mid-temperature thermochronometers (i.e., fission track, (U-Th)/He, and Ar/Ar) on resolving deep-time thermal histories of Precambrian crystalline basement rocks in the US Upper Midwest. The two main questions that we attempt to solve are the timing and/or mechanism(s) for: 1) the formation of the Neoproterozoic Great Unconformity surface, and 2) the more recent, Late Paleozoic thermal resetting events.

I am also interested in exploring avenues for improving our understanding of the zircon (U-Th)/He thermochronometer. Although there has been significant advancements in this method over the past ~2 decades, several questions and limitations remain. Understanding the He diffusion kinetics of zircons across a wide range of radiation damage levels is important in ensuring accuracies in thermal history interpretations. In particular, I am interested in exploring He diffusion kinetics at high radiation damage levels through step-heating experiments. Additionally I am also interested in using nano-scale imaging techniques such as the atom probe tomography to capture the behavior and distribution of He particles in zircons and to observe the crystallographic structure of zircons at various damage levels. These characterizations are important steps in fully capturing the intricacies of He diffusivity for the zircon (U-Th)/He system.