Outcrop and Grain-Scale Strain analysis of the Tuttle Lake Formation in the Mount Tallac Region; Desolation Wilderness Area, El Dorado County, California
Poster Number
1
Format
Poster Presentation
Faculty Mentor Name
Kurtis Burmeister
Faculty Mentor Department
Earth and Environmental Sciences
Abstract/Artist Statement
Preliminary analysis of the relationship between grain and outcrop-scale fabrics within exposures of the Tuttle Lake Formation in the Mount Tallac region suggests that more strain is accumulated at microscopic scales than previously suspected. Furthermore, the results of our strain analysis suggest the relationship between the magnitude of strain accumulated is proportional to proximity to igneous intrusions. The Tuttle Lake Formation is a thick unit of cross-bedded volcaniclastic breccia and conglomerate that is cut and deformed by numerous igneous intrusions, including at least five different dike sets and a pluton. We conducted detailed, three dimensional fabric analyses on samples from the Tuttle Lake Formation to examine the relationship between strain magnitudes and igneous contacts. Specifically, we prepared three, mutually perpendicular petrographic thin sections from samples collected during the summer 2014 field season. Photomicrographs of these thin sections were then used with the EllipseFit computer program (Vollmer, 2015) to conduct a normalized Fry analysis. The results of our analysis illustrate the magnitude and orientation of strain fabrics within the Tuttle Lake Formation and provide a basis for understanding how these fabrics evolved. An improved understanding of the strain history of the Tuttle Lake Formation will lead to a better understanding of the geologic evolution of the central Sierra Nevada.
Location
DeRosa University Center, Ballroom
Start Date
25-4-2015 2:00 PM
End Date
25-4-2015 4:00 PM
Outcrop and Grain-Scale Strain analysis of the Tuttle Lake Formation in the Mount Tallac Region; Desolation Wilderness Area, El Dorado County, California
DeRosa University Center, Ballroom
Preliminary analysis of the relationship between grain and outcrop-scale fabrics within exposures of the Tuttle Lake Formation in the Mount Tallac region suggests that more strain is accumulated at microscopic scales than previously suspected. Furthermore, the results of our strain analysis suggest the relationship between the magnitude of strain accumulated is proportional to proximity to igneous intrusions. The Tuttle Lake Formation is a thick unit of cross-bedded volcaniclastic breccia and conglomerate that is cut and deformed by numerous igneous intrusions, including at least five different dike sets and a pluton. We conducted detailed, three dimensional fabric analyses on samples from the Tuttle Lake Formation to examine the relationship between strain magnitudes and igneous contacts. Specifically, we prepared three, mutually perpendicular petrographic thin sections from samples collected during the summer 2014 field season. Photomicrographs of these thin sections were then used with the EllipseFit computer program (Vollmer, 2015) to conduct a normalized Fry analysis. The results of our analysis illustrate the magnitude and orientation of strain fabrics within the Tuttle Lake Formation and provide a basis for understanding how these fabrics evolved. An improved understanding of the strain history of the Tuttle Lake Formation will lead to a better understanding of the geologic evolution of the central Sierra Nevada.