Age and provenance of the fluvial Goldstein Peak unit Diane Clemens-Knott, Department of Geological Sciences, California State University, Fullerton, Fullerton, CA 92834 To study the extent to which new forearc basins are filled with purely arc-derived sediment, we have dated ≈60-100 zircons from each of 22 samples of the Early Cretaceous Goldstein Peak formation (GP), the Early Cretaceous (?) Gravelly Flat Formation, as well as older metamorphic rocks that might have provided zircons to the GP rivers and the forearc basin of the Mesozoic Sierra Nevada arc. Comparison of detrital zircon dates from the Goldstein Peak formation (bottom curve) with older metasediments to determine sediment provenance Shoo Fly 4 n=20
GP, CB samples (this study) Others: Memeti (2009); Harding et al. (2000)
Shoo Fly 3 n=22
Shoo Fly 2 n=20
Shoo Fly 1 n=30
Strawberry Mine n=97 Upper Wood Canyon Fm n=95 Carrera Quartzite n=94 FVF n=95 CB-110 n=81 Goldstein Peak n=279
0
200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400
Age (Ma)
sampling the Early Cretaceous (?) Gravelly Flat Formation This year, CSUF undergraduates sampled the Gravelly Flat formation, the stratigraphically lowest formation in the Great Valley Group (San Joaquin basin). Detrital zircon data will be used to (1) determine a quantitative estimate of the maximum age of deposition; and (2) test the study’s hypothesis that fluvial GP protoliths carried arc detritus into California’s Great Valley forearc basin.
zapping zircons at the U of A Laserchron lab
