The Pikes Peak batholith, Colorado front range, and a model for the origin of the gabbro—anorthosite—syenite—potassic granite suite

Barker, Fred G.; Wones, David R.; Sharp, William N.; Desborough, George A.

doi:10.1016/0301-9268(75)90001-7

Cited by 270 publications

(108 citation statements)

References 32 publications

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“…This argument is well comparable not only with the results from the feldspar Pb isotope data on the Dalongshan granitoids by Zhang (1988), but also with the positive ENd(T) values of +2.7 to +3.3 for the Archean am phibolites from the eastern Hebei Province by Huang et al (1986) and Jahn et al (1987). Re cent works on anoroganic granites suggest that they may form from primary magmas produced by partial melting of relatively anhydrous lower crustal source rocks (e.g., Barker et al, 1975;Collins et al, 1982;Anderson, 1983;Jackson et al, 1984). Furthermore, if the formation of lower crust was related to the extraction of sialic upper crustal material from the primitive man tle, the U-Pb isotope data of the Dalongshan granitoids lend support to the assumption by Jahn et al (1987) based on the Sm-Nd isotope data of the Archean amphibolites that the ex istence of the sialic crust can be looked back before 4 Ga ago.…”

Section: Discussionsupporting

confidence: 89%

Early archean inheritance in zircon from Mesozoic dalongshan granitoids in the Yangtze Foldbelt of Southeast China.

Zhang

Zheng²,

Maogong

et al. 1990

Geochem. J.

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Section: Discussionsupporting

confidence: 89%

Early archean inheritance in zircon from Mesozoic dalongshan granitoids in the Yangtze Foldbelt of Southeast China.

Zhang

Zheng²,

Maogong

et al. 1990

Geochem. J.

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“…Several genetic models have been proposed to interpret the formation of syenites, which mainly include: (1) partial melting of crustal rocks in a closed system at pressures typical of the base of over-thickened crust (Huang and Wyllie, 1986;Deng et al, 1998;Tchameni et al, 2001), (2) partial melting of mantle peridotites with subsequent differentiation (Bailey, 1987;Whalen et al, 1996;Conceicão et al, 2000;Litvinovsky et al, 2002;Wang et al, 2005;Yang et al, 2005), (3) fractional crystallization of alkali basalt magma (Parker, 1983;Middlemost, 1985;Brown and Becker, 1986;Thorpe and Tindle, 1992) or fractionation caused by silicate liquid immiscibility (Rajesh, 2003), and (4) magma mixing processes, particularly mixing of basic and silicic melts with subsequent differentiation of the hybrid liquid (Barker et , 1975;Sheppard, 1995;Zhao et al, 1995;Wickham et al, 1995;Vernikovsky et al, 2003). In doing so, it is important to have an integrated study of major elements, trace elements and ragiogenic isotopes in continental igneous rocks in order to decipher the nature of their sources (e.g., Zhang, S.-B.…”

Section: Petrogenesis Of Weiya Quartz Syenite Weiya Quartz Syenite: Cmentioning

confidence: 99%

Sr, Nd and O isotopic characters of quartz syenite in the Weiya magmatic complex from eastern Tianshan in NW China: Melting of the thickened juvenile lower crust

Zunzhong²,

et al. 2010

Geochem. J.

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New Sr-Nd-O isotopic data are reported for the early Triassic (early Indosinian) Weiya quartz syenite from eastern Central Tianshan, northwestern China, with the aim of documenting its possible source(s), constraining its petrogenesis and discussing its tectonic implications. Whole-rock Rb-Sr isochron of the Weiya quartz syenite rock yielded an age of 246.5 ± 4.8 Ma, which is well consistent with zircon SHRIMP U-Pb age. Additionally, the rock exhibits positive ε Nd (t) value (+1.36 to +1.66), medium I sr (0.7088 to 0.7090), "normal" δ 18 O value (6.9 to 8.1‰) and young Nd model ages (T DM = 0.88 to 0.91 Ga). Combined with their petrogaphic and geochemical characters, the Weiya quartz syenite is suggested to have been generated by partial melting of juvenile lower crust rocks at high temperature. The partial melting is attributed to intra-continental subduction, which resulted in thickening of the continental crust, delamination of the lithosphere root, underplating of mantle-derived magma and subsequent regional extension. Heat from underplated mantle magma caused melting of the overlying lower crustal rocks and consequent generattion of the quartz syenitic liquid. It is supposed that the intra-continental subduction was induced by tectonic conversion from the Paleo-Asian subduction-collision system to the Paleo-Thethys regime during the latest Permian or earliest Triassic in the eastern Tianshan.

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“…The late-stage plutons form 10% of the exposed PPB and are located within and marginal to the main stage of the batholith. They include two chemical series, one with a potassic trend, dominantly granitic and the other with a sodic trend, dominantly syenitic (Barker et al, 1975;Wobus, 1976;Wobus and Anderson, 1978). Rocks of the sodic series include syenite, quartz syenite and fayalite-and sodic amphibole-bearing granites; minor gabbro is also present.…”

Section: Pikes Peak Batholithmentioning

confidence: 99%

“…Representative analyses of biotites and amphiboles in the PPB are given in Barker et al (1975) and Giambalvo (1993). Shannon et al (1997) give representative analyses of biotites and amphiboles occurring in the RBG.…”

Section: Mineral Chemistrymentioning

confidence: 99%

Petrogenesis of Mid-Proterozoic granitic magmas: examples from central and west Texas

Smith

Barnes

Shannon

et al. 1997

Precambrian Research

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Circa 1.1 Ga granitic magmatism in Texas was manifested as two compositional groups: (1) the 1.12 Ga Red Bluff granitic suite in west Texas; and (2) 1.12-1.07 Ga granites of the Llano uplift of central Texas. Both suites share some characteristics typical of 'anorogenic' granites (e.g. potassium-and iron-rich bulk compositions, Fe-rich hydrous silicates, emplacement conditions involving low oxygen fugacities and water contents) and exhibit similar isotopic characteristics. However, rock associations, mineral chemistries, and trace element compositions of the two suites are distinct and no single petrogenetic model for the two suites is possible.The Red Bluff granitic suite includes cogenetic syenites, quartz syenites and granites; transitional ferrobasaltic dikes are also present. In contrast, syenitic and mafic rocks are not associated with the Llano granites. The Llano granites contain biotite and calcic amphibole with lower Fe/(Fe+Mg) ratios compared to those occurring in the Red Bluff rocks. Alkali amphiboles (e.g. arfvedsonite) occur in the Red Bluff granites but not in the Llano granites. The Red Bluff granitoids are characterized by high FeO T /MgO ratios, high (Na2O+K2O), high concentrations of HFSE and rare earth elements (REE), and other features typical of A-type, 'within-plate' granites [e.g. the Pikes Peak batholith (PPB)]. The Llano granites are geochemically distinct with generally higher P2O5 and Sr, lower Na2O, FeO T /MgO, Zr, Y and REE, and much lower Ta and Nb. Nd isotopic data overlap between the two granite suites and have 'juvenile' signatures. However, trace element data suggest different petrogeneses for the two suites. The Red Bluff suite is interpreted as having a direct derivation from mantle sources via extended fractional crystallization of basaltic parental magmas, with minor crustal assimilation. The Llano granites appear to represent anatectic melts derived from slightly older, juvenile crustal sources; some melts underwent fractional crystallization controlled by feldspar and accessory minerals.The petrology and geochemistry of ~1.1 Ga granites in Texas indicate that they should not be considered as part of a single 'anorogenic' magmatic event. The Red Bluff granitic suite was emplaced into a shelf sequence, north of the Grenville Front, within a broad zone characterized by mild extension. In contrast, Llano granites are late-stage intrusions emplaced into multiply deformed and metamorphosed crust, south of the Grenville Front, during or after waning stages of Grenville orogenesis.

show abstract

The Pikes Peak batholith, Colorado front range, and a model for the origin of the gabbro—anorthosite—syenite—potassic granite suite

Cited by 270 publications

References 32 publications

Early archean inheritance in zircon from Mesozoic dalongshan granitoids in the Yangtze Foldbelt of Southeast China.

Early archean inheritance in zircon from Mesozoic dalongshan granitoids in the Yangtze Foldbelt of Southeast China.

Sr, Nd and O isotopic characters of quartz syenite in the Weiya magmatic complex from eastern Tianshan in NW China: Melting of the thickened juvenile lower crust

Petrogenesis of Mid-Proterozoic granitic magmas: examples from central and west Texas

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