Research Article

Nature and Evolution of the Ore-Forming Fluids from Nanmushu Carbonate-Hosted Zn-Pb Deposit in the Mayuan District, Shaanxi Province, Southwest China

Table 2

A summary of fluid inclusion data for the Nanmushu Zn-Pb deposit.

Stage IStage IIStage III

Host mineralQSp(a)QDolSp(b)CalBrtQ
FIs size (μm)31861164042042031441648
Vapor (vol.%)5305305405201040525530520
Counts of FIAs617343430432128
(°C) of type I inclusions−31.3−20.7−58.7−34.7−21.3–51.6–51.3–20.8
(°C) of type I inclusions−27.2−21.3–37.0
(°C) of type I inclusions−9.4−2.4−7.6−3.8−10.3−2.8−8.3−1.2−9.4−3.6−11.9−2.8−15.4−1.8−6.9−1.2
(°C) of type I inclusions (mean)171340225314186264152265183276107202123187149195
Mean of (°C)239283223205238152165166
Salinity (wt.% NaCl equivalent)4.313.36.211.24.714.32.012.25.913.33.015.93.119.02.110.4
Salinity (wt.% NaCl + CaCl2 equivalent)6.611.611.614.8
Bulk density (g/cm3)0.730.960.750.920.850.980.840.980.840.950.921.030.911.040.900.99
Homogenization styleL + V → LL + V → LL + V → L
Laser Raman spectroscopic analysis of compositionH2O, CH4H2O, CH4, BitumenH2O, CH4, C4H6, Bitumen
Dominant aqueous-salt speciesH2O-NaClH2O-NaCl-CaCl2  ±  MgCl2H2O-NaCl-CaCl2  ±  MgCl2

, first melting temperature; , melting temperature of hydrohalite; , melting temperature of final ice; , total homogenization temperature; Brt, barite; Cal, calcite; Dol, dolomite; Q, quartz; Sp(a), fine-grained sphalerite from hydrothermal stage I; Sp(b), coarse-grained sphalerite from hydrothermal stage II; Notes. Salinity (wt.% NaCl equivalent) estimated by final ice melting temperature () of type I inclusions (Bodnar, 1993) [13]; Salinity (wt.% NaCl + CaCl2 equivalent) estimated by , , and of type I inclusions by using the Software Package Fluids (Steele-MacInnis et al., 2010) [16]. Bulk density of type I inclusions estimated using the equations of Bodnar (1993) [13]. Dominant aqueous-salt species concluded on the basis of and the microthermometry behavior of fluid inclusions.