Zircon Lu–Hf isotopic compositions of metaluminous and peralkaline A-type granitic plutons of the Emeishan large igneous province (SW China): Constraints on the mantle source J. Gregory Shellnutt a, * , Christina Yan Wang b , Mei-Fu Zhou c , Yueheng Yang d a Academia Sinica, Institute of Earth Science, 128 Academia Road Sec. 2, Nankang, Taipei 11529, Taiwan b Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China c Department of Earth Sciences, The University of Hong Kong, Hong Kong SAR, China d State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China article info Article history: Received 22 May 2008 Received in revised form 30 November 2008 Accepted 30 December 2008 Keywords: Zircon Lu–Hf isotope A-type granite Peralkaline Metaluminous Panxi region SW China abstract Permian A-type granitoids of the Emeishan large igneous province (ELIP) in the Panxi region, SW China, are predominantly peralkaline and metaluminous in composition. In situ zircon Hf isotopic compositions along with whole rock trace element and Nd isotopic data are used to examine the probable source char- acteristics of these A-type granitic plutons. Zircons from the Baima and Taihe peralkaline plutons have weighted average eHf (T) values of +8.7 ± 0.4 and +9.2 ± 1.0, whereas the Woshui and Huangcao metalumi- nous plutons have differing eHf (T) values (+8.6 ± 0.2 and +5.8 ± 0.3, respectively). Previous studies have suggested that the plutons were derived by differentiation (e.g. fractionation or partial melting) of mafic magmas from an enriched mantle source similar to oceanic island basalt with little or no contribution from the crust (eNd (T) = +1.3 to +3.2, Zr/Nb = 0.9–14.4, Rb/Nb = 0.1–8.4 and Th/Ta = <4.0). Therefore, we interpret the Hf isotopic data of the Baima, Taihe, Woshui and Huangcao plutons to be indicative of the Emeishan mantle plume. The similar zircon eHf (T) values of the Woshui and Baima plutons indicates that spatially and temporally associated peralkaline and metaluminous A-type granitic rocks can origi- nate from the same mantle source without crustal assimilation. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction The petrogenesis of A-type granitoids is controversial (Collins et al., 1982; Eby, 1992; Frost and Frost, 1997; Goodge and Vervoort, 2006; Bonin, 2007). Peralkaline granitoids are almost synonymous with A-type characteristics, whereas metaluminous and peralumi- nous are less likely to be so (King et al., 1997). Temporally and spa- tially associated peralkaline and metaluminous A-type granitic plutons are common within the continental crust although the individual rock types usually have mutually exclusive petrogenetic histories (Poitrasson et al., 1995; Frost and Frost, 1997; Shellnutt and Zhou, 2007). Spatial, temporal and geochemical evidence sug- gest that some peralkaline granitic rocks can form by fractionation of mantle-derived mafic parental rocks (Bonin, 2007; Shellnutt et al., in press). However, peralkaline rocks may have chemical characteristics (e.g. negative Nb anomaly and elevated 87 Sr/ 86 Sr) indicative of metasomatized lithospheric mantle or continental crust (Turner et al., 1992; Kemp et al., 2005; Yang et al., 2006). On the other hand, metaluminous granitic rocks are commonly thought to be derived from a mixed (crust + mantle) source (Poitrasson et al., 1995; Schmitt et al., 2000; Kemp et al., 2005; Bonin, 2007). The Late (260 Ma) Permian Emeishan large igneous province (ELIP) in SW China contains numerous A-type granitic plutons associated with layered mafic intrusions which host magmatic Fe–Ti–V oxide deposits (Zhou et al., 2002; Shellnutt and Zhou, 2007; Zhong et al., 2007). The plutons in the ELIP mainly occur in the Panxi region and are mostly peralkaline and metaluminous in composition. The peralkaline plutons contain hypersolvus feldspar, Fe–Na-rich pyroxene and amphibole, have high Ga/Al ratios and high field strength elements and negative Eu/Eu * values, all of which are characteristic of A-type granitic rocks (Loiselle and Wones, 1979; Whalen et al., 1987; Bonin, 2007). The metalumi- nous plutons are similar to the peralkaline plutons in having hypersolvus feldspar and high Ga/Al ratios, but they are poor in Th, U, Zr and Hf and have positive Eu/Eu * values. Previous Sr–Nd isotopic studies of the ELIP granitoids have suggested that the two types of plutons originated from the same mantle source (Shellnutt and Zhou, 2007, 2008). However, granitic rocks, espe- cially peralkaline rocks, may be susceptible to isotopic disturbance and thus the Rb–Sr and Sm–Nd isotopic system may not be well suited for characterizing their sources (Vervoort et al., 1996; 1367-9120/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.jseaes.2008.12.003 * Corresponding author. E-mail addresses: jgshelln@earth.edu.tw, gshellnutt@hotmail.com (J. Gregory Shellnutt). Journal of Asian Earth Sciences 35 (2009) 45–55 Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jaes