DESOLATION WILDERNESS – Dr. Burmeister returned to the Grass Lake study area in the Desolation Wilderness Area of the Eldorado National Forest this summer. Located only a 2.5 mile hike out of the Fallen Leaf Lake trailhead, the Grass Lake study area is an ideal place conduct research on the early history of the Sierra Nevada. This year, Dr. Burmeister was joined by Allison Severson from Arizona State University. Alli is a graduate student specializing in economic geology, metamorphic petrology, and structural geology. Together, Dr. Burmeister and Alli made an incredible amount of progress in the study area. They documented at least 4 sets of mafic-intermediate intrusions and collected samples from each. Brittany Klemm ('14) hopes to prepare these samples for bulk geochemical analysis by Dr. Michael Stewart at the University of Illinois in Spring 2014. They also uncovered a complicated history of ductile and brittle faulting that appears to record deformation before and after exhumation of the Sierras. Finally, they mapped the contact relationships between the metamorphosed conglomerates of the Tuttle Lake Formation and the relatively younger plutons that truncate these rocks to the south. In addition to mapping, the pair also began to experiment with ways of conducting outcrop-scale strain analysis of the deformed conglomerates in the Tuttle Lake formation. Dai Wilson ('14) plans to explore the development of these methodologies during his senior year at Pacific.