Characteristics and Metallogenic Significance of Melt-Fluid Inclusions of Shanshenfu Granite in the Hongyan Area,Inner Mongolia

Mao Chen; LXinbiao; Chen Chao; Cao Mingyu; Gun Minshan; Liao Pengcheng; Jia Qiyuan

doi:10.3799/dqkx.2016.011

Abstract：This study investigates the characteristics of the fluid and its mineralization potential in magmatic-hydrothermal phase by the inclusions study of the Shanshenfu granite located in the Hongyan area,Inner Mongolia.The study shows that the inclu-sions of the Shanshenfu granite can be divideddevided into three types includingof melt inclusions,melt-fluid inclusions and flu-id inclusions.The presence of melt-fluid inclusions indicates that granitic magma has experiencedgot through magmatic-hydro-thermal transition stage,which is confirmed by the large changes in homogenization temperatures (from 281 ℃ to >550 ℃) and the salinities(from 1.1% NaCl eqv to >66.8% NaCl eqv)from rock center lithofaciesphase to edge lithofaciesphase.We use inclusion isochors of different homogenization temperatures and salinitiesy together with water-saturated solidus of granitic magma to estimate the temperatures and pressures of exsolved fluids.Considering that the three-phase inclusions containing CO 2 have a good limitation to the smallest emplacement pressure,we estimate that the smallest emplacement depth of Shansh-enfu granite of range 7.6-9.5 km,exsolution temperature and depth of range 580-700 ℃ and 6.0-14.9 km,respectively.La-ser-Raman characteristics of inclusions show that the solid phases of melt-fluid inclusions contain strong oxidation substances such as barite,azurite and hematite,which indicates the strong oxidation in magmatic-hydrothermal system that is very benefi-cial for Cu enriched in the exsolved fluids under the conditions of high-pressure,high-temperature and high-salinity.Combined with the wild in situ mineralized alteration characteristics,we conclude that the Shanshenfu area has good mineralization poten-tial to form magmatic-hydrothermal deposit of Cu.