Revisiting the genesis of the adakite-like granitoids in collisional zones: water-fluxed melting of intermediate to felsic rocks with dilution by low Sr/Y phases

High Sr/Y granitoids in continental settings are sometimes erroneously regarded as the products derived from partial melting of thickened/delaminated mafic lower curst under relatively higher pressures (> 1.5 GPa) in a collisional orogenic setting.In fact, multiple magmatic processes in the trans-crustal magma system such as recycling of antecrysts, crustal assimilation, and fractional crystallization can create or modify primary 'adakitic' signature.As a result, the generation of adakitic magmas in continental settings remains controversial from a bulk-rock perspective.Here, we address the origin of adakitic plutonic rocks through geochemical and textural characterization of rock-forming minerals in the pyroxene-bearing, Zhuyuan granodiorite (West Qinling, China).The Zhuyuan granodiorite formed in a postcollisional setting, and primarily consists of resorbed orthopyroxene, three types of clinopyroxene, amphibole, two types of plagioclases, K-feldspar, biotite, and quartz.Type-1 Cpx has high XMg (70.0-81.7).Type-2 Cpx displays normal zoning and decreasing XMg (80.9 to 71.5) from the core to rim.Type-3 Cpx is reversely zoned, where the rims have higher XMg (75.5-86.9),Ni, Cr, suggesting a recharge event.Orthopyroxene has high Ni and Cr contents, as well as high XMg (80.9-82.8),indicative of antecrysts that grew in mafic magma reservoirs.The injection of magmas from different sources is supported by sieve-textured plagioclase and crystal size This is the peer-reviewed, final