ORIGIN AND STRUCTURAL CONTROLS OF XIAOBAN GOLD DEPOSIT, FUJIAN PROVINCE

Xiaoban gold deposit,as an altered fractured rock type,is situated in central Fujian Provincewhere metamorphic rocks of Middle Proterozoic Mayuan Group are widely distributed The ore-controlling structure of the deposit are low-angle faults-the detachment faults in the northwest of Puyang metamorphic core complex The low-angle faults are important impounding structure Their shape,attitude,scale and distribution control over those of the gold orebodies and the mechanical property over the mineralization-alteration type The ore-controlling structure also plays an important rule of geochemical interface in course of gold mineralization Information from sulfur, lead and strontium isotopes and REE characteristics shows that the source materials of the deposit were derived mainly from metamorphic rocks and subordinately from magma Isotopic dating made on Rb-Sr isochron age of altered mineral from the deposit indicates that the mineralization occurs in early Yanshanian And inclusion study indicates both magmatic and meteoric water sources for the ore fluid Based on these facts in combination with an analysis on regional structural evolution and the role played by structure in controlling ore geneses,a new conclusion can be drawn that Xiaoban gold deposit is a medium-low-temperature magmatic hydrotermal deposit controlled by lower-angle faults(detachment faults).