Date File Created Name of Creator 6/17/2009 Sheryl Singerling GeoRef Data 2008-110001 DN GeoRef TI "Chronology of pluton emplacement and regional deformation in thesouthern Sierra Nevada Batholith, California" AU "Saleeby, Jason B; Ducea, M N; Busby, Cathy J; Nadin, Elisabeth S;Wetmore, P H" AF "California Institute of Technology, Division of Geological andPlanetary Sciences, Pasadena, CA, United States (USA)" AF "Utah State University, United States (USA); University of Arizona atTucson, United States (USA); University of California, Santa Barbara,United States (USA); University of South Florida, United States (USA)" MT "Ophiolites, arcs, and batholiths; a tribute to Cliff Hopson" ED "Wright, James E; Shervais, John W" AF "University of Georgia, Department of Geology, Athens, GA, UnitedStates (USA)" CF "Ophiolites, batholiths, and regional geology; a session in honor ofCliff Hopson; Geological Society of America 2005 Cordilleran Sectionmeeting, San Jose, CA, United States, April 29-May 1, 2005" SO "Special Paper - Geological Society of America, vol. 438, pp.397-427,2008" IS 0072-1077 CD GSAPAZ IB 9.78081E+12 PB "Geological Society of America (GSA), Boulder, CO, United States (USA)" DE absolute age; alkaline earth metals; Bear Valley; California;Cretaceous; dates; deformation; emplacement; Erskine Canyon Sequence;faults; geochemistry; intrusions; isotope ratios; isotopes; KernCanyon Fault; magmatism; Mesozoic; metals; nesosilicates;orthosilicates; plutons; Sierra Nevada; Sierra Nevada Batholith;silicates; Sr-87/Sr-86; stable isotopes; strontium; tectonics; U/Pb;United States; zircon; zircon group AB "Cretaceous plutonic rocks of the southern Sierra Nevada batholithbetween latitudes 35.5 degrees N and 36 degrees N lie in a strategicposition that physically links shallow, subvolcanic levels of thebatholith to lower-crustal (-35 km deep) batholitnic rocks. Thisregion preserves an oblique crustal section through the southernSierra Nevada batholith. Prior studies have produced large U/Pb zircondata sets for an aerially extensive region of the batholith to thenorth of this area and for the lower-crustal rocks of the Tehachapicomplex to the south. We present a large set of new U/Pb zircon agedata that ties together the temporal relations of pluton emplacementand intra-arc ductile deformation for the region. We define fiveinformal intrusive suites in the area based on petrography, structuralsetting, U/Pb zircon ages, and patterns in initial (super 87) Sr/(super 86) Sr (Sr (sub 1) ). Two regionally extensive intrusivesuites, the 105-98 Ma Bear Valley suite and 95-84 Ma Domelands suite,underlie the entire southwestern and eastern regions of the studyarea, respectively, and extend beyond the limits of the study area. Athird regionally extensive suite (101-95 Ma Needles suite) cuts outthe northern end of the Bear Valley suite and extends for an unknowndistance to the north of the study area. The Bear Valley and Needlessuites are tectonically separated from the Domelands suite by theproto-Kern Canyon fault, which is a regional Late Cretaceous ductileshear zone that runs along the axis of the southern Sierra Nevadabatholith. The 105-102 Ma Kern River suite also lies west of theproto-Kern Canyon fault and constitutes the subvolcanic plutoniccomplex for the 105-102 Ma Erskine Canyon sequence, an approximately2-km-thick silicic ignimbrite-hypabyssal complex. The 100-94 Ma SouthFork suite lies east of the proto-Kern Canyon fault. It recordstemporal and structural relations of high-magnitude ductile strain andmigmatization in its host metamorphic pendant rocks commensurate withmagmatic emplacement. Integration of t! he U/Pb age data with structuraland isotopic data provides insights into a number of fundamentalissues concerning composite batholith primary structure, plutonemplacement mechanisms, compositional variations in plutons, and thechronology and kinematics of regional intra-arc ductile deformation.Most fundamentally, the popular view that Sierran batholithic plutonsrise to mid-crustal levels ( approximately 20-15 km) and spread outabove a high-grade metamorphic substrate is rendered obsolete. Age andstructural data of the study area and the Tehachapi complex to thesouth, corroborated by seismic studies across the shallow-level SierraNevada batholith to the north, indicate that felsic batholithic rocksare continuous down to at least approximately 35 km paleodepths andthat the shallower-level plutons, when and if they spread out, do soabove steeply dipping primary structures of deeper-level batholith.This steep structure reflects incremental assembly of the lower crustby multiple magma pulses. Smaller pulses at deeper structural levelsappear to be more susceptible to having source isotopic andcompositional signatures modified by assimilation of partial meltproducts from metamorphic framework rocks as well as previouslyplated-out intrusives. Higher-volume magma pulses appear to rise tohigher crustal levels without substantial compositional modificationsand are more likely to reflect source regime characteristics. Thereare abundant age, petro-graphic, and structural data to indicate thatthe more areally extensive intrusive suites of the study area wereassembled incrementally over 5-10 m.y. time scales. Incrementalassembly involved the emplacement of several large magma batches ineach ( approximately 50 km (super 2) -scale) of the larger plutons,and progressively greater numbers of smaller batches down to a myriadof meter-scale plutons, and smaller dikes. The total flux ofbatholithic magma emplaced in the study area during the LateCretaceous is about four times that mod eled for oceanic-island arcs.Integration of the U/P! b zircon age data with detailed structural andstratigraphic studies along the proto-Kern Canyon fault indicates thateast-side-up reverse-sense ductile shear along the zone was operatingby ca. 95 Ma. Dextral-sense ductile shear, including a small reversecomponent, commenced at ca. 90 Ma and was in its waning phases by ca.83 Ma. Because approximately 50% of the southern Sierra Nevadabatholith was magmatically emplaced during this time interval,primarily within the east wall of the proto-Kern Canyon fault, thetotal displacement history of the shear zone is poorly constrained.Stratigraphic relations of the Erskine Canyon sequence and itsrelationship with the proto-Kern Canyon fault suggest that it wasponded within a 102-105 Ma volcano-tectonic depression that formedalong the early traces of the shear zone. Such structures are commonin active arcs above zones of oblique convergence. If such is the casefor the Erskine Canyon sequence, this window into the early history ofthe ""proto-Kern Canyon fault"" could preserve a remnant or branch ofthe Mojave-Snow Lake fault, a heretofore cryptic hypothetical faultthat is thought to have undergone large-magnitude dextral slip inEarly Cretaceous time. The changing kinematic patterns of theproto-Kern Canyon fault are consistent with age and deformationalrelations of ductile shear zones present within the shallow-levelcentral Sierra Nevada batholith. and with those of the deep-levelexposures in the Tehachapi complex. This deformational regimecorrelates with flat-slab segment subduction beneath the southernCalifornia region batholithic belt and resultant tilting and unroofingof the southern Sierra Nevada batholith oblique crustal section. Theseevents may be correlated to the earliest phases of the Laramideorogeny." LA English FE "References: 96; illus. incl. 1 table, geol. sketch maps" PY 2008 PT Serial; Conference document; Analytic CP United States (USA) LL "Latitude:N353000,N354500 Longitude:W1180000,W1183000" CL 03 Geochronology; 16 Structural geology CY "GeoRef, Copyright 2008, American Geological Institute." UD 200819 DO 10.1130/2008.2438(14) AN 2008-110001 JV 438 JP 397-427 Sample Data Item Age Max_age Min_age LatDD LongDD Loc_prec Rock_Class Rock_Type Location_Name Sample_Description Collected_by Material State Units Ma Ma Ma DD DD DD Method 1 1 1 2 2 Sample Name E2 105.4 106.4 104.4 35.588 118.437 0.001 rhyolite volcanic Erskine Canyon quartz-alkali feldspar porphyry metarhyolite groundmass hornfelsic Saleeby and others whole rock California E3 105.1 105.7 104.5 35.589 118.433 0.001 rhyolite volcanic Erskine Canyon "quartz porphyry rhyolitic lapilli tuff, groundmass hornfelsic" Saleeby and others whole rock California E4 104 104.3 103.7 35.587 118.43 0.001 rhyolite volcanic Erskine Canyon "quartz porphyry rholitic tuff, fine stretched lapilli groundmass hornfelsic" Saleeby and others whole rock California E5 102.2 102.8 101.6 35.479 118.632 0.001 rhyolite volcanic Erskine Canyon "tectonitic quartz-feldspar porphyry lapilli tuff stretched pumice lapilli up to 50 cm length, schistose groundmass" Saleeby and others whole rock California E6 104.5 105.2 103.8 35.827 118.443 0.001 dacite volcanic Erskine Canyon "plagioclase porphyry dacite breccia, groundmass hornfelsic" Saleeby and others whole rock California E7 106.5 109.9 103.1 35.708 118.431 0.001 rhyolite volcanic Erskine Canyon quartz porphyry rhyolite. finely phyllonitic groundmass Saleeby and others whole rock California K1 105 105.3 104.7 35.875 118.456 0.001 granite plutonic Kern River k-feldspar-plagioclase-biotite porphyritic granite with fine-grained groundmass Saleeby and others whole rock California K2 104.3 104.8 103.8 35.77 118.485 0.001 granite plutonic Kern River mildly K-feldspar porphyritic granite Saleeby and others whole rock California K3 104 105.8 102.2 35.682 118.443 0.001 granite plutonic Kern River k-feldspar porphyritic protomylonitic granite Saleeby and others whole rock California K4 104.4 106.1 102.7 35.615 118.436 0.001 granite plutonic Kern River k-feldspar porphyritic granite Saleeby and others whole rock California K5 103.2 104 102.4 35.787 118.57 0.001 granite plutonic Portuguese Pass coarse-grained biotite granite Saleeby and others whole rock California K6 102.8 103.3 102.3 35.527 118.102 0.001 granite plutonic Bodfish Canyon coarse-grained biotite granite Saleeby and others whole rock California K7 102.5 103 102 35.498 118.399 0.001 granite plutonic Saddle Springs Road medium-grained hornblende biotite diorite comingled with granite Saleeby and others whole rock California K8 103.1 104 102.2 35.825 118.462 0.001 granite plutonic Baker Point "dacitic porphyry dike rock, fine biotite and alkali feldspar phenocrysts" Saleeby and others whole rock California B1 101.8 102.2 101.4 35.478 118.733 0.001 diorite plutonic Bear Valley Springs medium-grained hornblende diorite Saleeby and others whole rock California B2 101 101.3 100.7 35.507 118.687 0.001 tonalite plutonic Bear Valley Springs "hornblende-biotite tonalite, uncharacteristically poor in mafic enclaves" Saleeby and others whole rock California B3 100.1 100.8 99.4 35.351 118.571 0.001 tonalite plutonic Bear Valley Springs "foliated hornblende-biotite tonalite, rich in flattened mafic inclusions " Saleeby and others whole rock California B4 101.5 101.9 101.1 35.395 118.435 0.001 tonalite plutonic Bear Valley Springs "foliated-biotite hornblende tonalite, rich in flattebed mafic enclaves" Saleeby and others whole rock California B5 102.6 106.5 98.7 35.75 118.585 0.001 tonalite plutonic Bear Valley Springs coarse-grained mafic biotite tonalite Saleeby and others whole rock California B6 108.9 110.2 107.6 35.436 118.517 0.001 tonalite plutonic Bear Valley Springs foliated biotite tonalite with sparse mafic enclaves Saleeby and others whole rock California B7 113.2 114.2 112.2 35.451 118.589 0.001 tonalite plutonic Bear Valley Springs hornblende-biotite tonalite gneiss Saleeby and others whole rock California B8 98.4 98.6 98.2 35.454 118.734 0.001 tonalite plutonic Mount Adelaide coarse-grained biotite tonalite with sparse mafic inclusions Saleeby and others whole rock California B9 100.1 100.4 99.8 35.575 118.566 0.001 granodiorite plutonic Poso Flat coarse-grained biotite tonalite with sparse mafic inclusions Saleeby and others whole rock California B10 100.2 100.7 99.7 35.603 118.648 0.001 granodiorite plutonic Poso Flat coarse-grained biotite granodiorite poor in mafic inclusions Saleeby and others whole rock California N1 100.9 101.9 99.9 35.666 118.588 0.001 granodiorite plutonic Alder Creek medium-grained hornblende-biotite granodiorite Saleeby and others whole rock California N2 100.6 101 100.2 35.975 118.473 0.001 granodiorite plutonic Brush Creek mafic hornblende granodiorite with abundant mafic inclusions Saleeby and others whole rock California N3 98.5 99 98 35.826 118.6 0.001 tonalite plutonic Dunlap Meadow medium-grained hornblende-biotite tonalite Saleeby and others whole rock California N4 98.3 98.7 97.9 35.852 118.626 0.001 granodiorite plutonic Pine Flat medium-grained hornblende-biotite granodiorite Saleeby and others whole rock California N5 98.3 101.9 94.7 35.669 118.486 0.001 granodiorite plutonic Alta Sierra fine-grained biotite porphyritic granodiorite Saleeby and others whole rock California N6 97.4 98.9 95.9 35.976 118.569 0.001 granodiorite plutonic Peppermint Meadow medium-grained hornblende-biotite granodiorite Saleeby and others whole rock California N7 96.8 97.5 96.1 36.095 118.463 0.001 granodiorite plutonic Needles hornblende-biotite granodiorite with ductile deformation fabric Saleeby and others whole rock California N8 96 96.5 95.5 35.105 118.487 0.001 granodiorite plutonic Needles hornblende-biotite granodiorite Saleeby and others whole rock California N9 95.5 96.7 94.3 35.676 118.464 0.001 granodiorite plutonic Wagy Flat coarse-grained biotite granodiorite Saleeby and others whole rock California N10 95.9 97 94.8 35.426 118.42 0.001 granodiorite plutonic Wagy Flat coarse-grained biotite granodiorite Saleeby and others whole rock California S1 99.6 99.9 99.3 35.717 118.406 0.001 diorite plutonic Cyrus Flat poikilitic hornblende-hypersthene leucogabbro Saleeby and others whole rock California S2 99.3 100 98.6 35.982 118.359 0.001 granodiorite plutonic Sherman Pass coarse-grained hornblende-biotite leucogranodiorite Saleeby and others whole rock California S3 99 99.4 98.6 35.673 118.353 0.001 granodiorite plutonic Rabbit Island "medium-grained hornblende-biotite granodiorite, abundant mafic inclusions" Saleeby and others whole rock California S4 98.1 98.4 97.8 35.615 118.249 0.001 granodiorite plutonic Rabbit Island "medium-grained hornblende-biotite granodiorite, common mafic inclusions" Saleeby and others whole rock California S5 97 97.4 96.6 35.578 118.393 0.001 granodiorite plutonic Rabbit Island "medium-grained hornblende-biotite granodiorite, ductile deformation fabric" Saleeby and others whole rock California S6 94.9 95.7 94.1 35.563 118.147 0.001 granodiorite plutonic Rabbit Island "coarse-grained hornblende-biotite granodiorite, common mafic inclusions" Saleeby and others whole rock California S7 93.7 94.8 92.6 35.729 118.376 0.001 granodiorite plutonic Rabbit Island "medium-grained hornblende-biotite granodiorite, ductile deformation fabric" Saleeby and others whole rock California D1 95.2 96 94.4 35.848 118.349 0.001 granite plutonic Long Meadow medium-grained biotite granodiorite Saleeby and others whole rock California D2 94.7 95.1 94.3 35.709 118.416 0.001 granite plutonic Cannell Creek biotite granodiorite mylonite Saleeby and others whole rock California D3 93 94.5 91.5 35.701 118.235 0.001 granite plutonic Onyx fine-grained biotite-bearing granite Saleeby and others whole rock California D4 92.5 93.2 91.8 35.462 118.281 0.001 granodiorite plutonic Claraville k-feldspar porphyritic biotite granodiorite Saleeby and others whole rock California D5 91.9 92.3 91.5 35.38 118.342 0.001 granodiorite plutonic Claraville medium-grained biotite granodiorite-modest planar ductile deformation fabric Saleeby and others whole rock California D6 91.2 93.1 89.3 35.741 118.143 0.001 granodiorite plutonic Claraville k-feldspar porphyritic biotite granodiorite Saleeby and others whole rock California D7 90 91.9 88.1 35.791 118.05 0.001 granodiorite plutonic Claraville medium-grained biotite granodiorite Saleeby and others whole rock California D8 89.3 89.9 88.7 35.483 118.227 0.001 granodiorite plutonic Claraville medium-grained hornblende-biotite granodiorite Saleeby and others whole rock California D9 89.3 89.5 89.1 35.986 118.443 0.001 granite plutonic Castle Rock k-feldspar megacrystic biotite granodiorite protomylonitic Saleeby and others whole rock California D10 89 89.5 88.5 35.744 118.309 0.001 granite plutonic Castle Rock medium-grained biotite-granodiorite Saleeby and others whole rock California D11 87.1 87.5 86.7 35.857 118.407 0.001 granite plutonic Castle Rock "megacrystic k-felspar biotite granodiorite, mild ductile deformation fabric" Saleeby and others whole rock California D12 86.1 86.5 85.7 35.444 118.37 0.001 granodiorite plutonic Claraville leucogranite pegmatite Saleeby and others whole rock California D13 85.7 86.2 85.2 35.801 118.416 0.001 granite plutonic Goldledge leucogranite pegmatite mylonite Saleeby and others whole rock California D14 84.2 85.7 82.7 35.736 118.077 0.001 granite plutonic Claraville medium-grained biotite hornblende granite Saleeby and others whole rock California Method Data 1 U-PB6:ZIRC 77 2 TABLE 2008-110001