Smartville Volcanic complex
Smartville Volcanic complex
Late to Middle Jurassic
Mafic to intermediate plutonic and volcanic rocks. Intrudes the Slate Creek terrane, Shingle Springs complex (YSSS) near Folsom Lake (Folsom dike swarm of Saleeby, 1982). Zircon U-Pb ages of ~160-162 Ma from volcanic rocks in this unit have been reported (McJunkin and others, 1979; Saleeby and others, 1989b), but at least part of the unit is at least slightly older than the oldest (~165 Ma) intruding pluton (unit Gph). Structurally (and perhaps depositionally) overlies and(or) intrudes the Clipper Gap Formation (unit YACG) near Higgins Corner (Day and others, 1985; Day and Bickford, 2004). Includes several named granitic and gabbroic plutons [from north to south: Swedes Flat (unit Gsf), San Juan Ridge (Gsj), Pilot Peak (Gpp), Banner Grange (Gbg), and Pine Hill (Gph)]. Interpreted as a rifted volcanic arc.