Hastings Natural History Reservation

07 Jul, 05 PM - 08 Jul, 05 PM

U-Pb ages can be now measured on single crystals of zircons using multicollector ICP-MS. High-precision ages can be determined in-situ by laser ablation techniques, either on previously concentrated zircon fractions, or directly on thin sections. We can measure ages on spots as small as 20 microns. The technique has a precision similar to ion probe techniques but it is faster and cost-effective. This proposal seeks funding to help further develop the methodology (30%) and to apply it to a tectonic problem: resolving the age and provenance of metasedimentary framework rocks within the Salinian terrane, central California (70%). The technique development component consists of various tests for the magnitude of U-Pb fractionation in the instrument and better calibration of ablation rates. The application proposed here is a provenance study of the Sur Series, an extensive metasedimentary unit in central California. The origin and age of many framework rocks within the North American Cordilleran arcs (e.g. the California arc) remain unresolved because of high-grade metamorphic imprint during arc formation. Solving the provenance of the Sur Series can provide important constraints on the hypotheses of lateral translations along the continental margin and terrane accretion in the area. We test between three plausible original locations of the Sur Series: southern Sierra Nevada, southern Mexico, and northern California.

Visit #5545 @Hastings Natural History Reservation

Approved

Under Project # 4371 | Research

In-situ Zircon U-Pb Age Determination

faculty - University of Arizona

Reservation Members(s)

Mihai Ducea Jul 7 - 8, 2004 (2 days)
Group of 3 Faculty Jul 7 - 8, 2004 (2 days)

Reserve Resources(s) | Create Invoice

Bunk House Cottage 4 Jul 7 - 8, 2004