Mantle source of tephritic porphyry in the Tarim Large Igneous Province constrained from Mg, Zn, Sr, and Nd isotope systematics: Implications for deep carbon cycling

• DOI: 10.1130/b35902.1
• Publication Date: 2021-06-15T18:02:47Z
• Authors: Weiliang Kong; Zhaochong Zhang; Zhiguo Cheng; Bingxiang Liu; M. Santosh; Bowen Wei; Shan Ke; Lijuan Xu; Xingchao Zhang
• Keywords: Amphibole; Peridotite; Phenocryst; Fractional crystallization (geology)

Abstract The nature and source of magmatism associated with large igneous provinces (LIPs) remain disputed. Here we investigate the role recycled materials that contributed to mantle heterogeneity in Tarim Large Igneous Province (TLIP) China through integrated Zn–Mg–Sr–Nd isotopes a rare tephritic rock suite. Sr–Nd [(87Sr/86Sr)i = 0.70368–0.70629; εNd(t) −0.25–4.64] δ26Mg values (−0.23‰ −0.34‰) porphyries are consistent normal origin. In contrast, whole pyroxene phenocrysts yield δ66Zn +0.28‰ +0.46‰ +0.30‰ +0.39‰, which slightly heavier than those terrestrial (+0.16 ± 0.06‰) mid-oceanic-ridge basalts (MORBs) (+0.27 0.05‰). We exclude possibility heavy Zn Wajilitag caused by magmatic processes such as fractional crystallization partial melting correlate isotopic features altered oceanic crust along magnesite source. porphyry displays trace-element patterns similar melts from natural hornblendite, especially hornblendite + peridotite. Additionally, geochemical characteristics enrichment Nb Ta, depletion K, high TiO2, constant Na2O/K2O ratios also suggest were derived an amphibole-bearing sedimentary carbonates. Our study provides insight into contribution subducted beneath TLIP highlights subduction deep carbon cycle slab-lithosphere-plume interaction generation LIPs.