Yuba Rivers pluton
Yuba Rivers pluton
Late Jurassic, ~154-162 Ma
Biotite-hornblende tonalite and granodiorite grading northward into pyroxene diorite and gabbro southeast of Lake Oroville. This unit has zircon U-Pb ages of ~154-162 Ma (Edelman and others, 1989; Saleeby and others, 1989b; Day and Bickford, 2004; Rotberg, 2008), as well as a hornblende K-Ar age of ~146 Ma and a biotite K-Ar age of ~143 Ma (Evernden and Kistler, 1970).