I- and S-type granites in the Lachlan Fold Belt

Chappell, B. W.; White, A. J. R.

doi:10.1130/spe272-p1

Cited by 439 publications

(385 citation statements)

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“…The Daju felsic plutons do not contain aluminous minerals such as muscovite, tourmaline, cordierite, and garnet, and have a magmatic mineral assemblage with plagioclase, amphibole, and biotite (Figure 2f). Coupled with the negative correlation between P 2 O 5 and SiO 2 (supporting information Figure S5), and low A/ CNK values of 1.02 ( Figure 6), this suggests that they are I-type granites (Barbarin, 1999;Chappell & White, 1992Clemens et al, 2011), which is consist with the previous studies about the Gangdese batholiths Wen et al, 2008;Zhu et al, 2011). I-type granitoids can be produced by partial melting of hydrous, calc-alkaline to high-K calc-alkaline, mafic to intermediate metamorphic crustal rocks (Roberts & Nions (1991).…”

Section: Daju Granitoids and Their Enclavessupporting

confidence: 85%

Slab Breakoff of the Neo‐Tethys Ocean in the Lhasa Terrane Inferred From Contemporaneous Melting of the Mantle and Crust

Huang

Zeng

et al. 2017

Geochem Geophys Geosyst

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Oceanic slab breakoff significantly affects the thermal regime of the lithosphere during continental collision. This often triggers extension‐related mafic magmatism and crustal melting. It is generally accepted that the Neo‐Tethyan lithosphere subducted beneath the southern Lhasa Subterrane, resulting in the formation of the Gangdese magmatic arc. However, the timing of slab breakoff is still disputed, due to a lack of evidence for extension‐related mafic magmatism. In this study, we provide comprehensive age, element and Sr–Nd–Hf isotopic data of mafic dikes, felsic intrusions, and enclaves from the Daju area, southern Lhasa Subterrane. The timing of mafic dikes and granitoids are contemporaneous at circa 57 Ma. The mafic dikes are characterized by high Th/U, and Zr/Y ratios, their geochemistry indicates an intraplate affinity rather than arc magmas. Furthermore, the mafic dikes show strongly variable igneous zircon ɛHf(t), and lower whole‐rock ɛNd(t) than granitoids. This evidence suggests that the mafic dikes represent asthenosphere‐derived melts contaminated by various degrees of ancient lithosphere. However, the granitoids were directly derived from the juvenile lower crust. Given the abrupt decrease in the convergence rate between India and Asia, and the surface uplift and sedimentation cessation in the southern Lhasa Subterrane in the early Cenozoic, the occurrence of synchronous mafic dikes and granitoids is best explained by a slab breakoff model. The occurrence of intraplate‐type magmas likely corresponds to the magmatic expression of the initial stage of Neo‐Tethyan slab breakoff. The slab breakoff concept also explains the onset of the magmatic “flare‐up” and crustal growth after 57 Ma.

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Section: Daju Granitoids and Their Enclavessupporting

confidence: 85%

Slab Breakoff of the Neo‐Tethys Ocean in the Lhasa Terrane Inferred From Contemporaneous Melting of the Mantle and Crust

Huang

Zeng

et al. 2017

Geochem Geophys Geosyst

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“…This correlation is similar to the Early Cretaceous Kitakami area in Northeast Japan where granitoid magmatism and kurokoassociated volcanism occurred in an extensional environment (Sato et al, 2004a, b). It is also noticed that the oxidized Boggy Plain batholith (BP) is younger than the reduced S-type batholith in the same area (Gang Gang adamellite, Chappell et al, 1991;Hoskin et al, 2000), and this situation is consistent with secular variation of granitoid types in the circum-Japan Sea Foster and Gray (2000) in consideration of chronological and stratigraphical data for granitoid plutons (Chen & Williams, 1990;Williams, 1992Williams, , 2001Hoskin et al, 2000;Kemp et al, 2005), volcanic sequences related to volcanogenic massive sulfide (kuroko) deposits (Gulson, 1977;Glen, 1995) and intrusive or hydrothermally altered rocks related to porphyry Cu deposits (Carr et al, 1995;Perkins et al, 1995;Squire & Crawford, 2007). The I-type granitoids for which SHRIMP zircon ages are available are thought to be the oxidized type judging from the occurrence of accessory magnetite, although part of data for the Baga batholith (Bega) were obtained for mafic inclusions in granodiorite or tonalite (Chen & Williams, 1990).…”

Section: Fig 12 Distribution Of Tectonic Elements and Majormentioning

confidence: 99%

Sedimentary Crust and Metallogeny of Granitoid Affinity: Implications from the Geotectonic Histories of the Circum‐Japan Sea Region, Central Andes and Southeastern Australia

Sato

2012

Resource Geology

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Metallogeny of granitoid affinity was reviewed from the aspect of geotectonic history of the continental crust, particularly of the genesis of sedimentary crust involved in magmatism. The redox state of granitoids and related mineralization shows a remarkable contrast between the east and west sides of the Pacific Rim, but if examined closely, the reduced-type and oxidized-type granitoid provinces are juxtaposed in three regions: the circum-Japan Sea region, the central Andes, and the Lachlan Fold Belt in southeastern Australia. Comparative study of these regions revealed that the reduced-type magmatism associated with Sn mineralization generated in thick sedimentary crust which formed in three geotectonic environments: (i) accretionary terrane along a subduction zone (e.g. Jurassic East Asia), (ii) continental rift (e.g. Early Paleozoic Andes), and (iii) mega-fan (e.g. Early Paleozoic southeastern Australia). A collisional orogen can provide large amounts of clastic sediment to these environments. The age gap between the magmatism and sedimentation varies depending on the tectonic evolution of individual regions. Thin sedimentary crust may not play an essential role for the reduced-type magmatism. The oxidized-type magmatism associated with porphyry Cu and other mineralization generated in the crust which was initially carbon-free igneous crust or modified from sedimentary crust by magmatism. Subduction-related basaltic magmas are relatively oxidized, and may enhance fO 2 conditions of granitoid activity. Repeated magmatism in a monotonous convergent margin may be favorable for porphyry Cu mineralization as exemplified in the eastern Pacific Rim.

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“…It is well documented that peraluminous granites can be produced by partial melting of crustal rocks with dominant pelitic components (Clemens and Wall, 1981;Todd and Shaw, 1985;Stuckless, 1989). The HHLG contains muscovite and biotite, high SiO 2 , K 2 O/Na 2 O ratio, Rb, normative corundum, molar A/CNK ratio mostly >1 with low Nb/Th ratios, Sr content and high FeO tot /MgO ratios in biotite which are characteristic of their derivation from crustal materials (Chappell and White, 1992;Abdel-Rahman, 1994;Frost et al, 2001). The enrichment of LREE and depletion of HREE in the HHLG are more or less coincident with typical crustally derived granitoids (Holtz et al, 1989;Rogers and Greenberg, 1990).…”

Section: Source and Melting Processesmentioning

confidence: 99%

Microstructural and geochemical studies of Higher Himalayan Leucogranite: implications for geodynamic evolution of Tertiary Leucogranite in the Eastern Himalaya

Singh¹,

Singh²

2013

Geol. J.

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The Higher Himalayan Leucogranites (HHLG) intruded into the high grade rocks of the Higher Himalayan Crystallines (HHC) in Arunachal Himalaya of the Eastern Himalaya, yield distinctive field data, petrography, microstructures, geochemical and mineral chemistry data. The Arunachal HHLG are characterized by the presence of two micas; normative corundum; high contents of SiO2 (67–78 wt.%), Al2O3 (13–18 wt.%), A/CNK (0.98–1.44) and Rb (154–412 ppm); low contents of CaO (0.33–1.91 wt.%) and Sr (19–171 ppm), and a high ratio of FeO(tot)/MgO in biotite (2.54–4.82). These distinctive features, along with their strong depletion in high field strength elements (HFSE), suggest their affinity to peraluminous S‐type granite generated by the partial melting of crustal material. Geothermobarometric estimations and mineral assemblages of the HHC metapelites confirm that the HHLG were probably generated in the middle crust (~20 km) and the produced melts intruded the HHC in the form of sills/dykes. Microstructurally, the HHLG shows high temperature deformation features including chessboard extinction in quartz and cuspate/lobate grain boundaries between quartz and feldspars (plagioclase and K‐feldspar). The deformation microstructures suggest that the HHLG was deformed under early high temperature ductile deformation conditions. These fabrics were subsequently superimposed by later brittle deformation features associated with decreasing temperatures during the exhumation of the HHLG towards shallow structural levels at the time of Himalayan orogeny. Copyright © 2013 John Wiley & Sons, Ltd.

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I- and S-type granites in the Lachlan Fold Belt

Cited by 439 publications

References 58 publications

Slab Breakoff of the Neo‐Tethys Ocean in the Lhasa Terrane Inferred From Contemporaneous Melting of the Mantle and Crust

Slab Breakoff of the Neo‐Tethys Ocean in the Lhasa Terrane Inferred From Contemporaneous Melting of the Mantle and Crust

Sedimentary Crust and Metallogeny of Granitoid Affinity: Implications from the Geotectonic Histories of the Circum‐Japan Sea Region, Central Andes and Southeastern Australia

Microstructural and geochemical studies of Higher Himalayan Leucogranite: implications for geodynamic evolution of Tertiary Leucogranite in the Eastern Himalaya

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