Collaborative Research: How are Rhyolites Generated? Evaluating Models for the Volcanic-plutonic Connection in the Searchlight Magmatic System, Nevada

Stanford University, Stanford CA

Investigators

Abstract

Eruptions of high-silica rhyolite magma are explosive, violent, and potentially extremely hazardous events. However, questions of how, under what conditions, and over what timescales the magma bodies that source these eruptions are assembled remain debated. Resolving these issues is critical for understanding a variety of magmatic and crustal processes, ranging from the geochemical stratification of the crust to monitoring the volcanoes that source such dangerous eruptions for future hazards. A significant challenge to answering these questions lies in the difficulty in documenting the physical (e.g., temperature, pressure) and geochemical conditions in magmatic systems through time. Geophysical measurements on modern volcanoes can provide 'snapshots' of a magmatic system, but they cannot shed light on long-term changes that occur over tens of thousands to millions of years. One way to bridge this gap is to study ancient volcanoes where faulting and erosion have exposed both the material that erupted from the volcano and the un-erupted material that comprises the roots of these systems within the Earth's crust. Used in combination, these extrusive and intrusive deposits can be a powerful tool to understand longer-term processes. This project aims to investigate one such ancient volcano near Searchlight, Nevada (USA). More specifically, the PIs will produce a high-resolution (<50,000 years) temporal record spanning the magmatic system's 1-2 million year lifetime, with which they will establish the history of magma emplacement in the crust, geochemical trends, and the relative timing of the eruption(s). To do this, the researchers will utilize high-precision U-Pb zircon geochronology, whole-rock and mineral geochemistry and barometry, and thermal models. This record will shed light on the timescales over which magmas accumulate and are stored within the Earth's upper crust, the processes that occur in and affect the magma body prior to eruption, and potential eruption triggers. Funding will also support two postdoctoral researchers (1 female), research opportunities for undergraduate students at Princeton and Northeastern Universities, and participation in Princeton University's Teachers as Scholars program, which introduces local K-12 teachers to the Earth sciences and helps them in building science curricula for use in their classrooms. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.