Provenance of Upper Triassic strata in southwestern North America as suggested by isotopic analysis and chemistry of zircon crystals

Riggs, Nancy R.; Barth, Andrew P.; González–León, Carlos M.; Jacobson, Carl E.; Wooden, Joseph L.; Howell, Evan R.; Walker, J. Douglas

doi:10.1130/2012.2487(02)

Cited by 24 publications

(57 citation statements)

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“…The ages of plutons in this southern arc segment correlate closely to the ages reported here for the SIS and Koip sequence ash-fl ow tuffs, but this segment may have been largely nonmarine, as plutons mostly intrude Paleoproterozoic cratonal basement. It seems likely that magmatism in both the northern and southern segments of the arc was ongoing by Middle Triassic time, and combining the plutonic, volcanic, and detrital zircon records suggests that magmatism probably commenced in both segments as early as earli- Dickinson and Gehrels, 2009;Riggs et al, 2009). The other known Triassic volcanic section, south of our study area, is the problematic section in the Mineral King pendant in the southern Sierra Nevada.…”

Section: Age and Tectonic Settingmentioning

confidence: 87%

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et al. 2011

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Granitic and volcanic rocks in the eastcentral Sierra Nevada, western UnitedStates, record the earliest stages of magmatism in the eastern Sierra Nevada magmatic arc, allowing us to examine magma sources and connections between plutonic and volcanic processes in the initial stages of arc construction. The Scheelite Intrusive Suite is one of the largest in the Sierra Nevada region, and is composed of the Wheeler Crest Granodiorite, granite of Lee Vining Canyon, and Pine Creek Granite. The Pb/U zircon ages from each unit of the suite suggest assembly between 226 and 218 Ma. The Scheelite Intrusive Suite is a high-K calcic or calc-alkalic suite, compositionally broadly similar to the nearby Late Cretaceous Tuolumne and John Muir Intrusive Suites, though plutons of the Scheelite Intrusive Suite are consistently Ca and Fe rich and lower in Na. Although Triassic granodiorites are isotopically quite similar to nearby Late Cretaceous intrusive suites, the trend toward more isotopically primitive granites is in contrast to the constant or more whole-rock radiogenic Sr trends observed in younger intrusive suites. Along the western margin of the Scheelite Intrusive Suite, the basal Mesozoic volcanic section in the Saddlebag Lake pendant includes silicic volcanic rocks that are in part coeval and potentially comagmatic with Triassic plutonic rocks. Widespread quartz-phyric ash-fl ow tuffs of Black Mountain, Saddlebag Lake, and Greenstone Lake yield Pb/U zircon ages of 232, 224, and 219 Ma, indicating that felsic ignimbrite volcanism commenced earlier and continued during emplacement of the 226-218 Ma Scheelite Intrusive Suite. Ash-fl ow tuffs are hydrothermally altered but have high fi eld strength element abundances and Nd isotopic compositions, suggesting affi nity to the relatively felsic parts of the Wheeler Crest Granodiorite and the granite of Lee Vining Canyon.

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Section: Age and Tectonic Settingmentioning

confidence: 87%

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et al. 2011

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“…This study aims to investigate if chemical abrasion can be applied to LA-ICP-MS U-Pb zircon geochronology to reduce discordance. Although the technique has previously been applied to a small number of LA-ICP-MS U-Pb zircon studies [23][24][25], this particular application has not been rigorously assessed. We test a modified chemical abrasion technique by applying an annealing-leaching treatment to zircon reference materials and a range of zircons of unknown age.…”

Section: +mentioning

confidence: 99%

Chemical Abrasion Applied to LA-ICP-MS U–Pb Zircon Geochronology

et al. 2014

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Zircon (ZrSiO 4 ) is the most commonly used mineral in U-Pb geochronology. Although it has proven to be a robust chronometer, it can suffer from Pb-loss or elevated common Pb, both of which impede precision and accuracy of age determinations. Chemical abrasion of zircon involves thermal annealing followed by relatively low temperature partial dissolution in HF acid. It was specifically developed to minimize or eliminate the effects of Pb-loss prior to analysis using Thermal Ionization Mass Spectrometry (TIMS). Here we test the application of chemical abrasion to Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) by analyzing zircons from both untreated and chemically abraded samples. Rates of ablation for high alpha-dose non-treated zircons are up to 25% faster than chemically abraded equivalents. Ablation of 91500 zircon reference material demonstrates a ca. 3% greater down-hole fractionation of 206 Pb/ 238 U for non-treated zircons. These disparities necessitate using chemical abrasion for both primary reference material and unknowns to avoid applying an incorrect laser induced fractionation correction. All treated samples display a marked increase in the degree of concordance and/or lowering of common Pb, thereby illustrating the effectiveness of chemical abrasion to LA-ICP-MS U-Pb zircon geochronology. OPEN ACCESSMinerals 2014, 4 504

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“…Iriondo and Arvizu (2009) and Riggs et al (2009) recognized the Permian magmatism in Sonora to be associated with initiation of subduction along the southwestern margin of Laurentia; younger Permian and Triassic plutons of southeastern California and western Arizona were recognized as subduction-related arc rocks (Barth et al, 1997;Barth and Wooden, 2006). According to the age of this arc (~ 275 -221 Ma, as noted before), it must have been formed contemporaneously with movement of the California-Coahuila …”

Section: Interpretation Of Tectonic Settingmentioning

confidence: 99%

“…A petrographic study carried out by Lindner (2013) on fluvial sandstone of the Antimonio and Río Asunción sequences (coupled with the ages of clasts and detrital zircons) suggests that their compositionally and texturally immature detritus should have been derived from and recorded the unroofing of the nearby Permo-Triassic arc that was located to the north of the basin. Similarly, Riggs et al (2012) established a geochemical link between detrital zircon grains in the El Antimonio and Barranca groups with Triassic plutonic suites of the Mojave Desert. Dickinson and Lawton (2001) recognized a distinction between the Permo-Triassic and Jurassic arcs, suggesting a hiatus of arc magmatism during Middle Triassic time.…”

Section: Introductionmentioning

confidence: 99%

“…Also, igneous clasts dated from the Antimonio and Río Asunción formations range in age from ca. 280 to 240 Ma (Riggs et al, 2009(Riggs et al, , 2010Lindner, 2013 The tectonic setting of the El Antimonio basin has been proposed to be a fore-arc basin (Stanley and González-León, 1995;González-León, 1997a;Lucas et al, 1999;González-León et al, 2005). The Lower Jurassic (Hettangian-Sinemurian-Toarcian) Sierra de Santa Rosa Formation records deeper-water depositional environments and increased rates of sedimentation regarding to the Antimonio and Río Asunción formations .…”

Section: Introductionmentioning

confidence: 99%

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