The genesis and mineralization significance of Guanyintang high Ba-Sr granitic intrusive rocks in the central section of the Taihang Mountains

A series of high Ba-Sr granitoids, developed in the Taihang Mountains region, are associated with a large amount of metal mineralization. To analyze their genesis is of great significance for studying the crust-mantle interaction and the evolution of its corresponding magmatic mineralization system in the destruction process of the North China Craton. This study takes the Guanyintang intrusion in the central section of the Taihang Mountains as an example to conduct zircon U–Pb geochronological, lithogeochemical, and genetic mineralogical researches of its different rocks. The research results show that main components of the Guanyintang intrusion are quartz monzonite, granodiorite, with minor diorite as the marginal phase of the intrusion. The compositions of dikes associated with the intrusion are consistent with those of main components of the Guanyintang intrusion. The diorite was formed at 125.2 Ma. Three measured ages for porphyritic quartz monzonite, granodiorite, and porphyritic granodiorite are 124.6 Ma, 129.9 Ma, and 130.33 Ma, respectively. The Lu-Hf isotopic characteristics of zircons indicate that the Guanyintang intrusion was formed by the mixture of acidic magma produced by the partial melting of ancient crust and basic magma produced by the partial melting of lithospheric mantle. Characteristics of the zoning texture of orthoclase indicate that the Guanyintang high Ba-Sr granitoid was formed by the mixture of the granitic magma in the magma chamber and the mantle derived magma which were intruded into the acidic magma chamber in multiple pulsations.