Abstract: Four types of primary fluid inclusions developed in quartz that intergrowth with goldbearing pyrite in the Linglong gold deposit, namely, Ⅰ aqueous two-phase; Ⅱ carbon dioxide-bearing three-phase; Ⅲ carbon dioxide and Ⅳ only liquid aqueous phase, respectively. The laser Roman spectroscopic analysis for composition and the microthermometric study of fluid inclusions indicate that: ①type Ⅰa fluid inclusions, in which the vapor volumes occupy 10%-15%, their homogenization temperature is 162.7-235.6℃, salinity is 4.65%-7.59% NaCl, the average composition of vapor phase is 96.48 mol% H₂O and 2.4 mol% CO₂; ② type Ⅰb fluid inclusions, in which the vapor volumes occupy 30%-45% , their homogenization temperature is 266.9-349.2℃, salinity is 10.8%-13.4% NaCl, the average composition of vapor phase is 69.75 mol% H₂O and 24.74 mol% CO₂; ③ type Ⅱ fluid inclusions, with a wide range of 20%-90% for the carbon dioxide volumes in fluid inclusions, their homogenization temperature is 193.5-321.6℃, salinity is 2.9%-5.3% NaCl, the average composition of the carbon dioxide phase is 27.72 mol% H₂O and 70.60 mol% CO₂. Comprehensive study of compositional and microthermometric analysis of fluid inclusions leads to the conclusion that fluid mixing between meteoric water-derived and mantle-derived hydrothermal solutions existed in the metallogenetic process of Linglong gold deposit. The former are mixed with CO₂-rich fluids separated from mantle-derived solutions and then captured at different ratios formed type Ⅱ fluid inclusions; whereas mixed with CO₂-unsaturated fluids which was the remnants of mantle-derived solutions after CO₂ separation, could be captured to form type Ⅰb fluid inclusions. The changes in physico-chemical conditions of ore-forming solutions resulted from two kinds of fluid mixing have great significances to gold mineralization.

Key words: Linglong gold deposit of Shandong Province, fluid mixing, microthermometry of fluid inclusion, Laser Roman spectroscopic analysis of composition