Triassic Appinite from the Qinling Orogen (Central China): Hydrous Melting of Depleted Mantle Wedge in Post-Collision Stage

Mantle wedge melting and the formation of hydrous mafic melts in collision orogenic belts have great significance for crustal related granitic magmatism, which can provide key messages about crustal–mantle interaction convergent margin. This paper reported Late-Triassic appinite (212 ± 2 Ma), is closely associated with granites. The large euhedral hornblende crystals indicate a water-rich feature. displays low SiO2 (46.55% to 50.44%) contents, high MgO (7.62 10.76%) Cr Ni Mg# values 61 75. It also insignificant Eu anomalies (Eu*/Eu = 0.91 0.93), Sr (596 676 ppm) contents moderate Sr/Y (34 40) ratios; these features are similar those Sanukite formed by mantle wedge. Its depleted zircon Lu-Hf isotopic composition (εHf(t) +0.97 +18.21) indicates source. Zircons display extremely Ti-in temperatures (>1000 °C) oxygen fugacity, indicating high-temperature condition. In combination its typical arc-like trace element geochemistry (depletion Nb, Ta Ti), it proposed that this represents derived from sub-arc occurrence has further understanding Triassic magmatism potential magmatic metal ore deposits Qinling belt.