COMPLEXLY INTERLEAVED PERMIAN TO MID-CRETACEOUS VOLCANO-SEDIMENTARY ROCKS IN THE MINERAL KING PENDANT, SOUTHERN SIERRA NEVADA, CALIFORNIA INDICATE MULTIPLE DEFORMATIONS PRIOR TO AND SYNCHRONOUS WITH CRETACEOUS BATHOLITH EMPLACEMENT

The Mineral King pendant is an elongate, 15-km long, NW-striking assemblage of late Pz to mid-Cretaceous metavolcanic and metasedimentary rocks that forms a steeply dipping wall rock screen between large mid-Cretaceous plutons of the Sierra Nevada batholith.

On-going structural studies and new U/Pb zircon ages indicate five volcano-sedimentary packages: (1) Permian arkosic and volcanoclastic sandstones with detrital zircon ages of ~266 Ma; (2) Late Triassic (~236 to 214 Ma) siliceous hornfels, calcsilicate hornfels and marble with interleaved andesite; (3) Early Jurassic (~196 to 171 Ma) dacite and rhyolite tuff, and quartz biotite and calcsilicate schists; (4) Early Cretaceous (140 to 135 Ma) voluminous rhyolite tuffs; and (5) middle Cretaceous (<117 to 100 Ma) small plutons and felsic volcanic rocks. The pendant is bounded by two large plutons of the Sierra Nevada batholith, the Granodiorite of Castle Creek (98 Ma) and the Granite of Coyote Pass (99 Ma).

Volcanic and sedimentary units are metamorphosed to greenschist facies and characterized by variably developed, NW-striking, steeply dipping, flattening foliation and steeply NW-plunging stretching lineation. Dated stratigraphic packages are discontinuous and complexly interleaved, and are interpreted to be structurally imbricated by a combination of km-scale tight to isoclinal folding and cryptic thrust(?) faulting, accentuated by pervasive flattening and vertical extension. Deformation post-170 to pre-135 Ma is indicated by angular discordance between 135 Ma rhyolite tuffs and older units, whereas vertical tilting and isoclinal folding of 135 Ma tuffs indicates post-135 Ma contractional deformation. Tilting, flattening and vertical extension at ~100 Ma are indicated by vertically-dipping rhyolite tuffs with ages ranging from 105 to ~100 Ma, extensively boudinaged pegmatite dikes dated at 107 Ma, and isoclinally folded aplite dikes dated at 98 Ma (Sisson and Moore, 2013). Close juxtaposition of rhyolite tuffs deposited subaerially at ~100 Ma and large granitic plutons crystalized at ~11 km depth at 98 Ma (Klemetti et al., 2013) suggests very rapid downward displacement of Mineral King pendant rocks during upward emplacement of granitic plutons.