Grant Funds at Work

Yoshinobu & Barnes Receive Grant to Study Histories of Galice & Mariposa Basins

9.13.2021 | College of Arts & Sciences

Aaron Yoshinobu and Cal Barnes, both professors in the Department of Geosciences, have recently received a grant from the National Science Foundation (NSF) for their research project, “Testing models for the Late Jurassic Nevadan Orogeny: Age, provenance, and structural evolution of the Galice and Mariposa basins, Oregon and California.”

The $368,003 grant will allow them, in collaboration with Kathleen Surpless of Trinity University in San Antonio, to improve geologists' understanding of how the North American continental margin in southern Oregon and northern California developed.

Their work will take them not only to the West Coast but also back in time, so to speak, to study the geologic processes that occurred in the region during the age of the dinosaurs, an estimated 160 to 145 million years ago, they say.

Yoshinobu and Barnes describe this western margin as geologically very active, with alternating periods of widespread volcanic activity punctuated by periods of compressional deformation (folding and faulting) and the potential for mountain building. A record of this activity is preserved in sediments shed from the continental margin and nearby volcanic regions.

Specifically, they'll be comparing two distinct sedimentary sequences. One occurs in far northern California and southwestern Oregon, an area known as the Galice basin. The other lies in the foothills of the Sierra Nevada in California's gold country, also called the Mariposa basin.

Their research will encompass both field and lab work as they compare the geologic histories of both sedimentary sequences and then test whether the histories are geologic equivalents or whether they formed in different ways.

Field work will involve detailed mapping and sampling of selected areas of each basin along with analysis of the history of rock deformation.

When they return to the lab, they'll begin with characterization of the sediments deposited in each basin through detailed microscopic examination followed by separation of dense minerals. Among these dense minerals, zircon is particularly important because it can be radiometrically dated, thereby indicating the ages, and potential locations, of sediment sources.

Other dense minerals will be analyzed for their trace element contents, which will assist in identifying specific source regions. The combined data will be used to determine whether the two basins were geologically similar, and to test conflicting theories of their origins.

The grant, which began Sept. 1, 2021, and is estimated to run through August 31, 2024, will benefit students as well. Graduate and undergraduate geology students from Texas Tech University will join undergraduates from Trinity University as they take part in hands-on research.