Crystallization conditions of Wushi diorite-hornblende gabbros in Fogang granitoid complex,Guangdong Province

The Fogang granitoid complex is the largest Late Mesozoic batholith in Nanling region, and the Wushi diorite-hornblende gabbros are the most basic end-member of Fogang calc-alkaline series rocks. Both the Wushi diorite-hornblende gabbros and the surrounding granite-granodiorites belong to high-K calc-alkaline series. Based on a systematic comparison of different Al-in-hornblende geobarometers and hornblende-plagioclase geothermometers, the authors have proposed an improved temperature and pressure grid of Al-Ti in hornblende and applied it to estimating crystallization conditions of Wushi diorite-hornblende gabbros. Hornblendes in Wushi diorite-hornblende gabbros crystallized at 820±20℃ and 70～130 MPa, with a X-(H-2O) of 0.7±0.1. The hornblendes in surrounding granodiorites crystallized at 820℃ and 260 MPa.