Joe P. Blaylock

The following is the abstract of my thesis project proposal for a Master of Science degree in geology from the Department of Geoscience at UNLV. This work is being funded by the Center for Volcanic and Tectonic Studies.

The recently proposed concept of polygenetic volcanism in Quaternary small volume basaltic centers suggests that models of monogenetic cinder cone formation are oversimplified. Polygenetic volcanic activity could have severe implications regarding the proposed geologic repository for high-level nuclear waste at Yucca Mountain, Nevada. The most recent Quaternary volcanic activity (Lathrop Wells and Crater Flat) has occurred within 10 km of Yucca Mountain. The Sunset Crater volcanic chain is similar to the Lathrop Wells and Crater Flat centers with respect to style and type of volcanism, age, structural control, and (possibly) having a polygenetic history, and therefore will be studied as an analog site. The study of analogs of volcanoes near Yucca Mountain is important because recurring volcanism will more likely occur at or near the sites of the youngest eruptions.

The Sunset Crater volcanic chain, comprised of four vents forming a volcanic chain 10 km long oriented N60W and three associated flows, is in eastern part of the San Francisco volcanic field, Arizona. This study will primarily use geochemical data to interpret the petrogenesis of the Sunset Crater volcanic chain. Major, trace and rare-earth element, and isotope data will be obtained from approximately 50 samples that will be strategically collected to produce a representative suite. Studies such as this will aid in the development/assessment of volcanic hazard models applied to the proposed nuclear waste repository.