Linking crustal deformation with its thermal structure, from fault spacing to strain rates

Abstract

The strength of the crust—both continental and oceanic—is fundamentally controlled by its thermal structure. That is, warmer crust is weaker and vice versa. This simple characteristic dictates how the crust deforms, including deformation geometry and rates. In this talk, I explore two case studies on this topic. First, we have observed a striking correlation between strike-slip fault spacing and brittle-crust thickness in various continental settings (i.e., central Asia, western US, New Zealand), analog sandbox models, and even icy satellites. Brittle-crust thickness is controlled by geothermal gradient, and we discuss the impacts of this thermal gradient on controlling fault geometries. Second, in the North American Basin and Range Province widespread volcanism precedes short-lived (~1 Myr) fast intracontinental extension. We examined one of these coupled magmatic-extension systems, and explore the hypothesis that fast extension rapidly advects hot rocks to cool the upper crust. Efficient crustal cooling strengthens the crust and slows further fast extension. Simple modeling of this negative feedback matches the observed geologic record. Feedbacks between deformation and thermal structure are important for continental evolution.

Biography

Andrew Zuza is an Assistant Professor at the University of Nevada, Reno and received his PhD from UCLA and BS from Cornell University. He is a field-based structural geologist focused on studying crustal deformation. Andrew and his research group are currently working on several intriguing continental dynamics issues, including crustal thickening during orogenic plateau development and subsequent collapse, the crust’s thermal structure in modern and ancient settings and how this affects deformation rates and styles, and tectonic reconstructions of western North America and central Asia. Andrew teaches structure and field methods courses at UNR, including the capstone summer field course.

ResearchGate: https://www.researchgate.net/profile/Andrew_Zuza

Google Scholar: https://scholar.google.com/citations?user=CvGEH7UAAAAJ&hl=en&oi=ao

Venue

This seminar will be held using the video conferencing software, Zoom. If you would like the link, please email sees.seminars@uq.edu.au