A reconnaissance U-Pb study of detrital zircon in sandstones of peninsular California and adjacent areas

Gastil, R. Gordon; Girty, Melissa S.

doi:10.1130/spe279-p135

Cited by 7 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Multigrain U-Pb analysis of detrital zircons in the Julian Schist and related units in southern California, however, are interpreted as mixtures of late Paleozoic and early Mesozoic grains, together with a blend of Precambrian zircons averaging ca. 1540 Ma (Gastil et al, 1988;Gastil and Girty, 1993).…”

Section: Plate-tectonic Setting Of Jurassic Magmatismmentioning

confidence: 96%

Jurassic peraluminous gneissic granites in the axial zone of the Peninsular Ranges, southern California

Shaw¹,

Todd²,

Grove

2003

Tectonic Evolution of Northwestern Mexico and the Southwestern USA

View full text Add to dashboard Cite

The Peninsular Ranges batholith of southern California and Baja California, México, is well recognized as a prime example of an I-type Cretaceous batholith. Often overlooked, however, is a volumetrically signifi cant amount of pre-Cretaceous gneissic granite in the axial zone of the batholith. New U-Pb zircon age data confi rm that the metaluminous and peraluminous plutonic bodies were emplaced during the middle Jurassic. Also reported in this paper is a Jurassic U-Pb age for a metaluminous (I-type) tonalite-quartz diorite pluton that is spatially related to the peraluminous suites. This result suggests that other unrecognized Jurassic I-type plutons may also be present in the batholith.Within San Diego County, Todd and Shaw (1985) recognized and mapped two suites of strongly deformed gneissic granites and migmatites. One is peraluminous (Harper Creek suite) while the other is transitional between metaluminous and peraluminous (Cuyamaca Reservoir suite). These rocks bear a striking resemblance to deformed and, in places, migmatitic, peraluminous (S-type) examples from the Lachlan fold belt and New England batholith of eastern Australia. The gneissic granite suites are known to extend north along the axial zone of the Peninsular Ranges batholith and cover an area at least 45 km wide by 150 km long. To the south, rocks of similar type are known to extend into Baja California, México, for at least 300 km. Chemical and isotopic studies of these Jurassic suites confi rm that they meet the criteria necessary to defi ne them as S-type and transitional I-to S-type, respectively. However, unlike the majority of Lachlan fold belt S-type granites that are high level and often associated with their volcanic equivalents, the Peninsular Ranges batholith suites were emplaced at much deeper levels, possibly as much as 11-16 km. The Harper Creek suite, of S-type gneissic granodiorite-tonalite plutons and associated Stephenson Peak migmatitic schist and gneiss facies, is strongly peraluminous and contains biotite, cordierite, sillimanite, abundant graphite, and ilmenite. It has elevated δ 18 O up to +20 per mil, initial 87 Sr/ 86 Sr ratios (Sr i ) to 0.713, a high aluminum saturation index, and Na 2 O/K 2 O ratios that overlap those of the Lachlan fold belt S-type granites. The Cuyamaca Reservoir suite contains gneissic granodioritetonalite plutons, transitional between metaluminous and moderately peraluminous (Ito S-type), containing reduced biotite, subaluminous amphibole, orthopyroxene, titanite Shaw, S.E.,

show abstract

Section: Plate-tectonic Setting Of Jurassic Magmatismmentioning

confidence: 96%

Jurassic peraluminous gneissic granites in the axial zone of the Peninsular Ranges, southern California

Shaw¹,

Todd²,

Grove

2003

Tectonic Evolution of Northwestern Mexico and the Southwestern USA

View full text Add to dashboard Cite

show abstract

“…The zircons have an inherited Precambrian component (Gastil and Girty, 1993). North of El Arco, an orthogneiss unit in the Sierra San Pedro Martir yielded an U-Pb age of 164.4 ± 1.2 Ma with a Precambrian inherited component (Schmidt, 2000).…”

Section: Evidence Of Jurassic Magmatismmentioning

confidence: 99%

“…Furthermore, different age determinations of El Arco rocks have been used in studies and interpretations of the Mesozoic tectonic evolution of northwest Mexico and Baja California (i.e., Gastil et al, 1975Gastil et al, , 1981Rangin, 1978b;Gastil and Miller, 1984;Radelli, 1989;Gastil and Girty, 1993;Wetmore et al, 2003). However, the age of El Arco porphyry copper deposit is poorly constrained, with K-Ar dates ranging from 93 to 138 Ma.…”

Section: Introductionmentioning

confidence: 97%

Re–Os and U–Pb geochronology of the El Arco porphyry copper deposit, Baja California Mexico: Implications for the Jurassic tectonic setting

Valencia

Barra

Weber

et al. 2006

Journal of South American Earth Sciences

View full text Add to dashboard Cite

“…Volcaniclastic rocks that contain Tithonian Buchia and a fl ow or dike that yielded a U-Pb zircon age of about 152 Ma originally were assigned to the Santiago Peak Volcanics (Balch et al, 1984), but probably are correlative with the Bedford Canyon Formation (Wetmore et al, this volume). Detrital zircons suggest Late Proterozoic and Paleozoic to early Mesozoic sources and may have been derived from igneous rocks of these ages in Arizona and northwestern México (Gastil and Girty, 1993).…”

Section: Basinal Assemblage (Bedford Canyon Complex)mentioning

confidence: 99%

Geology and tectonics of the Baja California Peninsula and adjacent areas

Sedlock¹

2003

Tectonic Evolution of Northwestern Mexico and the Southwestern USA

View full text Add to dashboard Cite

A reconnaissance U-Pb study of detrital zircon in sandstones of peninsular California and adjacent areas

Cited by 7 publications

References 0 publications

Jurassic peraluminous gneissic granites in the axial zone of the Peninsular Ranges, southern California

Jurassic peraluminous gneissic granites in the axial zone of the Peninsular Ranges, southern California

Re–Os and U–Pb geochronology of the El Arco porphyry copper deposit, Baja California Mexico: Implications for the Jurassic tectonic setting

Geology and tectonics of the Baja California Peninsula and adjacent areas

Contact Info

Product

Resources

About