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Description
Previous investigators utilized a petrologically-based provenance-discrimination model to interpret the source of siliciclastic sandstone turbidites within the post-Cambrian and preUpper Devonian Red Hill unit of the Shoo Fly Complex, northern Sierra Nevada, California. The results of this work indicated an average framework composition of Q94,f'4L1. In addition, some quartz framework grains displayed abraded syntaxial overgrowths. On the QFL provenance-discrimination diagram of W. R. Dickinson and colleagues, point-counted samples from the Red Hill unit plot mostly in the continental interior provenance. Thus, I, as well as several previous workers,interpret the source of sandstones within the Red Hill unit to have been old upper continental crust located along or somewhere within the interior of North America. In order to determine whether or not the chemically-based provenance-discrimination model produces an interpretation that is consistent with the petrologically-based discrimination model of W. R. Dickinson and colleagues, five samples of quartz-rich sandstone collected from the Red Hill unit were analyzed for major, trace, and REE. The average AI2 O}/Ti02 ratio based on this work is 16.4 .± 1.4. The average Th/U ratio is 5.6 .± 0.8. Moreover, the five analyzed samples of sandstone display LREE enriched and slightly HREE fractionated chondrite-normalized REE patterns with an average Euanomaly of 0.67 .:t 0.06. These results are consistent with the petrological results obtained by previous workers and thus indicate that both the petrologically- and chemically-based provenancediscrimination models yield internally consistent results when applied to siliciclastic sediments derived from the interiors of continents.
