Petrogenesis of Transitional Large Igneous Province: Insights From Bimodal Volcanic Suite in the Tarim Large Igneous Province
Zhiguo Cheng, Zhaochong Zhang, Zhenchao Wang, Fangyue Wang, Qian Mao, Lijuan Xu, Shan Ke, Huimin Yu, M. Santosh
Abstract
Abstract The Tarim large igneous province (TLIP) corresponds to a transitional large igneous province based on the high proportion of felsic rocks, classifying between mafic and silicic large igneous provinces. Here we investigate a bimodal suite including trachydacite, rhyolite, and basanite from the Northern Tarim Uplift using petrological, geochemical, stable, and radiogenic isotopic techniques with a view to understand the formation of the TLIP. Our study reveals a multistage origin involving multiple components, although the various rock suites are genetically linked and formed under a rift incubation setting related to mantle plume. The low δ 26 Mg values (−0.48‰ to −0.71‰), Fe/Mn > 60, FC3MS (FeO T /CaO‐3*MgO/SiO 2 ) > 0.65, and high TiO 2 contents (4.45–4.93 wt.%) of basanite from this suite suggest formation through partial melting of carbonated eclogite formed by recycled oceanic crust. The thick lithosphere beneath the Tarim Craton promoted extensive interaction between the underplated basaltic magmas and crust‐derived magmas leading to the formation of multistage magma chambers. Geochemical and mineralogical studies suggest that the trachydacite experienced a mixing, assimilation, storage, and hybridization process, whereas the rhyolite was produced by fractional crystallization from the associated mantle‐derived magma with significant crustal contamination. The abundance of amphibole in the trachydacite suggests a hydrous parental magma with H 2 O content in the range of 2.75 to 4.05 wt.%. Our results suggest that hydrous crustal components contributed significantly in the formation of voluminous felsic rocks of the TLIP.