Sequence 4
Sequence 4
Jurassic
Volcanic and nonmarine volcaniclastic sedimentary rocks of the Inyo Mountains volcanic complex of Dunne and others (1998) and the unnamed Jurassic-Triassic volcanic and continental sedimentary rocks unit of Ross (1967a). Unconformably overlies the Union Wash Formation of Sequence 3 (Stone and others, 1991). Zircon U-Pb dates from the more volcanic middle part of the unit range from ~168-169 Ma, whereas those from the volcanic interbeds in the more sedimentary upper part of the unit range from ~148-163 Ma (Dunne and others, 1998). Intruded by dikes of the Independence Dike Swarm (unit Gid) and the granite of French Spring (part of unit Gsp) which has a zircon U-Pb age of ~148 Ma (Dunne and Walker, 1993).