Buck Meadow intrusive suite
Buck Meadow intrusive suite
Jurassic, ~146-175 Ma
Occurs in southern Sierra Nevada, east of the north fork of the Kern River. Chiefly tonalite and granodiorite, with lesser gabbro and granite. Generally metamorphosed to upper amphibolite facies. This unit has yielded zircon U-Pb ages of ~146-175 Ma (Saleeby and Dunne, 2015; Clemens-Knott and Gevedon, 2025), consistent with a whole-rock Rb-Sr age of ~177 Ma (Ross, 1995). The unit as mapped also has an anomalous age of ~94 Ma in the northernmost part of the unit (Clemens-Knott and Gevedon, 2025) which is probably a body too small to map of the adjacent Mount Whitney Intrusive Suite (unit Gwh).  Major plutons: Sacatar Quartz Diorite, Summit gabbro, quartz diorite of Round Mountain, tonalite of Falls Creek, alaskite of Kern Peak, granodiorite of Church Dome, quartz diorite of Long Valley, granodiorite of Schaefer Meadow, granodiorite of Redrock Meadow, granodiorite of Monache Creek, granite of Haiwee Creek, and gabbro of Deer Mountain. As mapped, also includes the small granite of Noname Canyon, granite of Sand Canyon, and unnamed felsic bodies in the southeasternmost part of the unit, but the granite of Noname Canyon has a Rb-Sr age of ~81 Ma and the granite of Sand Canyon is tentatively correlated with the ~90 Ma granodiorite of Castle Rock, so these are inliers too small to map of the adjacent Cretaceous Owens Peak intrusive suite. On its eastern margin, intruded by Late Jurassic Independence Dike Swarm (unit Gid). Ross (1995) suggests that the hornblende K-Ar ages were reset at the time the dikes were intruded, and the undeformed ~148 Ma Long Valley pluton was also intruded at that time. The unit also has whole rock or hornblende K-Ar ages of ~145-146 Ma and a biotite K-Ar ages of ~81 and ~88 Ma which have been thermally reset by younger intrusions (Bergquist and others, 1982). Clemens-Knott and Gevedon (2025) suggest that the Summit Gabbro and the quartz diorite of Long Valley should be excluded from this unit and combined with the Osa Ring complex (unit Gido) into their Summit igneous complex.