Soldier Pass Intrusive Suite
Soldier Pass Intrusive Suite
Late and Middle Jurassic, ~148-196 Ma
Crops out in the Inyo Mountains. Chiefly granodiorite and quartz monzonite. Major plutons in the study area: Paiute Monument Quartz Monzonite, Pat Keyes pluton of the Hunter Mountain Quartz Monzonite, Santa Rita Flat pluton, granite of French Spring (Ross, 1967b; 1969; Dunne and Walker, 1993; Dunne and others, 1998). Intrudes and overlaps in age with the Jurassic Sequence 4 of the White-Inyo Mountains Craton Margin Formations (unit I4), which are largely volcanic and volcaniclastic, so these plutons may be part of the same arc system. The youngest plutonic rocks of this unit are also coeval with the adjacent Independence Dike Swarm (unit Gid), but that unit extends far beyond the extent of the intrusive suite, so their proximity probably indicates the development of the dike swarm cutting through the final stages of the older arc regime. Zircon U-Pb ages from this unit range ~148-196 Ma (Chen, 1977; Chen and Moore, 1979; Dunne and Walker, 1993). This unit also has biotite K-Ar ages of ~123-157 Ma, hornblende K-Ar ages of ~156-178 Ma, and apatite fission track age of ~93 Ma (Kistler and others, 1965; Evernden and Kistler, 1970; Naeser and Dodge, 1969). This unit differs from the formally accepted definition of Bateman (1992) in age and extent based on the subsequent work cited above.