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Vishnu Schist

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Journal Article
Journal: Geology
Published: 01 December 2010
Geology (2010) 38 (12): 1099–1102.
...Owen P. Shufeldt; Karl E. Karlstrom; George E. Gehrels; Katherine E. Howard Abstract U-Pb dating of 1035 detrital zircons from 12 spatially distributed samples of the Paleoproterozoic Vishnu Schist (Arizona, United States) reveals a bimodal 207 Pb/ 206 Pb age probability diagram with peaks at 1.8...
FIGURES
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Compiled Vishnu Schist U-Pb-Hf data show that the Vishnu Schist was derived from an Archean craton characterized by extensive crustal reworking at ca. 1.8 Ga, ca. 2.5 Ga, and ca. 3.2 Ga. DM—depleted mantle; CHUR—chondritic uniform reservoir.
Published: 01 September 2015
Figure 10. Compiled Vishnu Schist U-Pb-Hf data show that the Vishnu Schist was derived from an Archean craton characterized by extensive crustal reworking at ca. 1.8 Ga, ca. 2.5 Ga, and ca. 3.2 Ga. DM—depleted mantle; CHUR—chondritic uniform reservoir.
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Comparison and synthesis of new and previous Vishnu Schist detrital zircon U-Pb age data. (A) Composite age probability plot taken from Shufeldt et al. (2010). (B) New detrital zircon ages obtained for this study. (C) New composite age probability plot with all current Vishnu Schist detrital zircon ages. (D) Age probability plots of Vishnu Schist detrital zircon samples arranged by river mile (OS0878–1 = Owen Shufeldt [2008], river mile 78), normalized as in Figure 5. Results from Shufeldt et al. (2010) are filled light gray; new results obtained in this study are filled black. See also Table DR1 for detrital zircon age data (see text footnote 1).
Published: 01 September 2015
Figure 6. Comparison and synthesis of new and previous Vishnu Schist detrital zircon U-Pb age data. (A) Composite age probability plot taken from Shufeldt et al. (2010) . (B) New detrital zircon ages obtained for this study. (C) New composite age probability plot with all current Vishnu Schist
Journal Article
Journal: GSA Bulletin
Published: 01 September 2015
GSA Bulletin (2015) 127 (9-10): 1391–1410.
...Figure 10. Compiled Vishnu Schist U-Pb-Hf data show that the Vishnu Schist was derived from an Archean craton characterized by extensive crustal reworking at ca. 1.8 Ga, ca. 2.5 Ga, and ca. 3.2 Ga. DM—depleted mantle; CHUR—chondritic uniform reservoir. ...
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Journal Article
Journal: GSA Bulletin
Published: 01 September 1996
GSA Bulletin (1996) 108 (9): 1149–1166.
...Bradley R. Ilg; Karl E. Karlstrom; David P. Hawkins; Michael L. Williams Abstract Paleoproterozoic supracrustal rocks of the Upper Granite Gorge are divided into three mappable units: the Rama, Brahma, and Vishnu Schists, here collectively named the “Granite Gorge Metamorphic Suite.” The Brahma...
Journal Article
Journal: Geosphere
Published: 21 April 2021
Geosphere (2021) 17 (3): 786–803.
... parts of the orogen. The 91-Mile peridotite exhibits spectacular cumulate layering. Contacts with the surrounding Vishnu Schist are interpreted to be tectonic, except along one margin, where intrusive relations have been interpreted. Assemblages include olivine, clinopyroxene, orthopyroxene, magnetite...
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Plate-tectonic cartoons illustrating possible scenarios for the depositional setting of the Vishnu Schist and lithospheric formation in the Grand Canyon region. Cartoons are drawn approximately to scale; however, crustal thickness is exaggerated. Both models meet at ca. 1740 Ma (E) when the tectonic history of the Grand Canyon region is well constrained by the work of Ilg et al. (1996), Hawkins et al. (1996), and Dumond et al. (2007). (A) Pre–1750 Ma there exists no Yavapai-type crust in the region. The Mojave arc is evolving as early as 1780 Ma. (B) Deposition of the Vishnu Schist during final convergence between the newly formed Yavapai arc and Mojave Province. Vishnu Schist is deposited across both provinces (and at least in part on the Elves Chasm Gneiss) from 1750 to 1740 Ma in a trench-fill sequence receiving most of its sediment from the Mojave Province, plus a cratonic source. (C) Alternatively, pre–1750 Ma the Yavapai and Mojave Provinces are already joined. While no >1750 Ma Yavapai crust exists in the Grand Canyon region, older Yavapai crust exists to the northeast in Colorado. (D) The Vishnu Schist is deposited across both provinces in a back-arc basin after the juxtaposition of older Yavapai crust against Mojave. (E) By 1740 Ma, the arc has migrated such that calk-alkaline plutons begin to intrude the Vishnu Schist. Thrust stacking imbricates Vishnu turbidites with arc plutons, and a shallow S1 foliation develops. The Crystal shear zone (Csz) manifests as a boundary between Mojave and Yavapai crust. Arc plutons continue to intrude the Vishnu Schist until ca. 1710 Ma. (F) From 1710 to 1690 Ma, the transect undergoes protracted crustal shortening during the Yavapai orogeny, a penetrative subhorizontal fabric (S2) is developed throughout the transect, and the Crystal shear zone is transposed into this orientation. The transect is intruded by crustal melts, but no longer by calk-alkaline plutons, suggesting that the arc has either migrated or terminated. By 1700 Ma, the transect resides at midcrustal levels. The box straddling the Mojave-Yavapai boundary shows the cross section of Figure 14 at 1700 Ma.
Published: 01 September 2015
Figure 15. Plate-tectonic cartoons illustrating possible scenarios for the depositional setting of the Vishnu Schist and lithospheric formation in the Grand Canyon region. Cartoons are drawn approximately to scale; however, crustal thickness is exaggerated. Both models meet at ca. 1740 Ma (E
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Google Earth images of portions of the west face of Frenchman Mountain. (A) Exposure of the Cambrian strata and the location of the Frenchman Mountain Dolostone (FMD) stratotype near East Lake Mead Boulevard. Vishnu Basement is the 1.7 Ga Vishnu Schist and associated granite. (B) The most easily accessed exposure of the FMD and associated units. Ss.—Sandstone.
Published: 23 March 2023
Figure 10. Google Earth images of portions of the west face of Frenchman Mountain. (A) Exposure of the Cambrian strata and the location of the Frenchman Mountain Dolostone (FMD) stratotype near East Lake Mead Boulevard. Vishnu Basement is the 1.7 Ga Vishnu Schist and associated granite. (B
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Field photo of the Zoroaster pluton showing one of many screens of Vishnu Schist included within the pluton.
Published: 01 September 2015
Figure 13. Field photo of the Zoroaster pluton showing one of many screens of Vishnu Schist included within the pluton.
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U-Pb-Hf isotopic data from zircons separated from 1.78 to 1.74 Ga Mojave Province plutonic rocks shown in white (Wooden et al., 2012) compared to the Vishnu Schist. DM—depleted mantle; CHUR—chondritic uniform reservoir.
Published: 01 September 2015
Figure 12. U-Pb-Hf isotopic data from zircons separated from 1.78 to 1.74 Ga Mojave Province plutonic rocks shown in white ( Wooden et al., 2012 ) compared to the Vishnu Schist. DM—depleted mantle; CHUR—chondritic uniform reservoir.
Image
Google Earth image of the west face of Frenchman Mountain showing the entire Cambrian section as well as a portion of underlying crystalline basement rocks (consisting of the 1.7 GA Vishnu Schist and associated granite). The canyon left of center in this image contains the stratotype. Inset: Frenchman Mountain, looking north from the exposure east of East Bonanza Road. Ls—Limestone; Ss.—Sandstone.
Published: 23 March 2023
Figure 11. Google Earth image of the west face of Frenchman Mountain showing the entire Cambrian section as well as a portion of underlying crystalline basement rocks (consisting of the 1.7 GA Vishnu Schist and associated granite). The canyon left of center in this image contains the stratotype
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Paired U-Pb-Hf isotopic data for all supracrustal lithologies in Grand Canyon. Each diamond represents a zircon with paired U-Pb and Lu-Hf isotopic data. DM—depleted mantle of Vervoort and Blichert-Toft (1999); CHUR—chondritic uniform reservoir of Bouvier et al. (2008). Sample K12–79.6R is of the Rama Schist (shown in red); all other data are Vishnu Schist. Below are normalized detrital zircon age probability plots of grains for which we have obtained Lu-Hf isotopic data.
Published: 01 September 2015
–79.6R is of the Rama Schist (shown in red); all other data are Vishnu Schist. Below are normalized detrital zircon age probability plots of grains for which we have obtained Lu-Hf isotopic data.
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Synthesis of all U-Pb-Hf data from plutonic and detrital samples in Grand Canyon. Vishnu Schist is shown in blue, plutons east of the Crystal shear zone (Csz) in green, and plutons west of the Crystal shear zone in red. The dramatic difference in plutonic zircons is apparent. Paradoxically, the plutonic data suggest a suture across the shear zone, but the detrital zircon data do not. DM—depleted mantle; CHUR—chondritic uniform reservoir.
Published: 01 September 2015
Figure 11. Synthesis of all U-Pb-Hf data from plutonic and detrital samples in Grand Canyon. Vishnu Schist is shown in blue, plutons east of the Crystal shear zone (Csz) in green, and plutons west of the Crystal shear zone in red. The dramatic difference in plutonic zircons is apparent
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207Pb/ 206Pb age histograms and age probability plots of older grains (older than 2.2 Ga). A: Vishnu Schist samples. B: Wyoming craton. C: Gawler craton of Australia. D: South China craton. E: North China craton. F: Antarctica. G: Siberian craton. Data were compiled from igneous zircon crystallization ages and detrital zircon from ca. 1.7 Ga and older metasedimentary rocks. See Table DR3 (see footnote 1) for all compiled ages and references.
Published: 01 December 2010
Figure 2. 207 Pb/ 206 Pb age histograms and age probability plots of older grains (older than 2.2 Ga). A: Vishnu Schist samples. B: Wyoming craton. C: Gawler craton of Australia. D: South China craton. E: North China craton. F: Antarctica. G: Siberian craton. Data were compiled from igneous
Journal Article
Journal: AAPG Bulletin
Published: 01 January 1961
AAPG Bulletin (1961) 45 (1): 95–97.
...Robert A. Hodgson The dial diagram ( Fig. 1 ) summarizing strike readings of all joints shows that the dominant directions of jointing are northeast and northwest and correspond rather closely with directions of faulting and schistosity in the Vishnu schist and with folding in the overlying...
FIGURES
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Chemostratigraphy and biostratigraphy of the Frenchman Mountain succession compared to the composite global reference curve. Durations of Cambrian stages at right are scaled linearly, whereas the Frenchman Mountain succession at left is scaled to rock thickness of the succession; the blue dashed lines indicate approximate tie points between stage boundaries and illustrate how excursions in the Frenchman Mountain section compare directly with global patterns. Key elements include the N5 and N6 excursions of Lin et al. (2019) in the upper Bright Angel and basal Muav Formations, respectively; a cryptic disconformity or condensed interval in the upper Muav; the global Drumian Carbon Isotope Excursion (DICE) at the base of the Frenchman Mountain Dolostone (FMD); and the Steptoean Positive Carbon Isotope Excursion (SPICE), which spans the FMD to Nopah Formation transition. Global curve at right is assembled from Chang et al. (2017), Saltzman et al. (2000), Zhu et al. (2004), and Peng et al. (2012), per Cramer and Jarvis (2020). Due to font size limitations, the trilobite zones between Peachella iddingsi and Mexicella mexicana and between Aphelaspis and Elvinia are not repeated from Figure 12. C refers to stable carbon isotope ratios in marine carbonate rocks. ROECE—Redlichiid-Olenellid Extinction Carbon isotope Excursion; Lyndon—Lyndon Limestone; Rampart—Rampart Cave Member of Muav Formation; Sanup—Sanup Plateau Member of Muav Formation; SC—Spencer Canyon Member of Muav Formation; Peach Springs—Peach Springs Member of Muav Formation; Kanab—Kanab Canyon Member of Muav Formation; G—Gateway Canyon Member of Muav Limestone; Havasu—Havasu Member of Muav Formation; Vishnu—Vishnu Schist; Tapeats—Tapeats Sandstone; Bright Angel—Bright Angel Formation; Muav—Muav Formation; Frenchman Mountain—Frenchman Mountain Dolostone; Nopah—Nopah Formation; Mtn. Spr.—Mountain Springs Formation; Sultan—Sultan Limestone; D—Dunderberg Shale; HS—Halfpint and Smoky members; Furon—Furongian Series; St—Steptoean Stage; Pai—Paibian Stage; Jiang—Jiangshanian Stage; Ser.—series.
Published: 23 March 2023
of Muav Formation; Peach Springs—Peach Springs Member of Muav Formation; Kanab—Kanab Canyon Member of Muav Formation; G—Gateway Canyon Member of Muav Limestone; Havasu—Havasu Member of Muav Formation; VishnuVishnu Schist; Tapeats—Tapeats Sandstone; Bright Angel—Bright Angel Formation; Muav—Muav Formation
Journal Article
Journal: AAPG Bulletin
Published: 01 November 1946
AAPG Bulletin (1946) 30 (11): 1899–1909.
... on the eastern side of the fault and the Tapeats sandstone rests directly on the Vishnu schists. 2. On the north side of the Colorado River, near the mouth of Bright Angel Canyon, where 1,500 feet of Unkar sediments are exposed below the Tapeats sandstone on the western side of the fault and the Tapeats...
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Journal Article
Journal: Geosphere
Published: 01 December 2016
Geosphere (2016) 12 (6): 1774–1794.
... in the Jerome Canyon sandstone. A distinctive population of similar-age zircons was also identified in ten samples of Vishnu Schist ( Ilg et al., 1996 ; Karlstrom et al., 2012 ) from ∼150 km to the north-northeast in eastern Grand Canyon, and in two samples of schist from western Grand Canyon ( Billingsley...
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Journal Article
Journal: GSA Bulletin
Published: 01 November 1951
GSA Bulletin (1951) 62 (11): 1331–1346.
...CHARLES A ANDERSON Abstract The older Precambrian rocks of Arizona include the Vishnu, Yavapai, and Pinal schists, all overlain unconformably by nonmetamorphosed younger Precambrian rocks. The older Precambrian schists, unnamed gneisses, and associated granitic masses crop out in many...
Published: 01 January 1978
DOI: 10.1130/MEM152-p341
... faults from Cataract Creek on the southwest to the Echo Cliffs on the northeast. Beyond the Echo Cliffs, the system continues northeastward to the vicinity of Monument Valley as a more diffuse, discontinuous zone of normal faults. The Bright Angel fault, Vishnu fault, and Eminence Break graben are among...