Van Tuyl Lecture: Kurtis Burmeister, University of the Pacific
April 18, 2019 @ 4:00 pm - 5:00 pm
Kurtis Burmeister, University of the Pacific
241 Berthoud Hall, 4-5PM
Topic: Welcome to Jurassic Arc: Insights from a Remarkably Preserved Sierra Nevadan Remnant
Abstract: The Sierra Nevada are best known for breath-taking exposures of granitic rocks in places like Yosemite Valley, Kings Canyon, and the Tahoe Basin. These rocks are part of the Sierra Nevada batholith, which is part of a massive granitic backbone that spans much of the length of western North America. These granitic rocks offer us interesting glimpses into how pulses of intensive igneous activity built the Sierra Nevada batholith during the Mesozoic. However, earlier chapters in this geologic story are often difficult to unravel because processes associated with batholith emplacement tend to obliterate preexisting rocks. Fortunately, these preexisting rocks are preserved in a few isolated locations throughout the Sierra Nevada. The rarity of these exposures is significant, because the relationships they preserve provide our only basis for understanding the timing and mechanisms behind the earliest states in the geologic evolution of this region. The Mt Tallac roof pendant near South Lake Tahoe is one of the largest and best exposed of these exposures, and contains a portion of a Jurassic volcanic arc. Over the past several years, undergraduate students working with Dr Burmeister applied a variety of techniques, including geologic mapping, petrography, geochemistry, strain analysis, and paleomagnetic analysis in the Mt Tallac pendant to begin to resolve the details associated with what appears to be a very rapidly evolving arc… and one that is surprisingly undeformed given its geologic history.