1503_651674.pdf — page 17

Chen et al.: Metallogenic setting and material source of Caihong copper-lead-zinc polymetallic deposit 
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APPLIED ECOLOGY AND ENVIRONMENTAL RESEARCH 15(3): 651-674. 
http://www.aloki.hu ● ISSN 1589 1623 (Print) ● ISSN 1785 0037 (Online) 
DOI: http://dx.doi.org/10.15666/aeer/1503_651674 
 2017, ALÖKI Kft., Budapest, Hungary 
did not achieve fractionation equilibrium. Lamellar ores were formed in active 
epicontinental sea basin environment (Shan et al., 2009; Zheng and Chen, 2000). Due to 
the multi-source mechanism of seawater sulfate reduced sulfur as well as possible 
mixing process of magmatic sulfur and reduced sulfur, the unequilibrium relation 
among sulfur isotopes of this kind of symbiotic sulfide is very common in seafloor 
massive sulfide deposit(An et al., 2003; Zeng et al., 2007; Xue et al, 2011). The 
statistical analysis of sulfur isotope of more than 100 massive sulfide deposits shows 
that the sulfur of VMS type deposit has certain correlation with that of seawater in the 
same period. That is to say, the δ34S value of VMS type sulfide deposit is about 15% 
less than that of seawater sulfate (Sangster, 1983), and the sulfate of seawater in the 
same period is a possible sulfur source of these sulfide deposits (Zeng et al., 2007; Xiao 
and Ni, 2000). In this test, the δ34 S value of lamellar ore sulfide was between 4.37 and 
6.87‰. While, the δ34 S component range of marine sulfate in the late period of the 
Early Paleozoic Era was between 20‰ and 25‰ (Hoster, 1977; Rees et al., 1978), and 
the difference value in 15‰~18‰ existed. Therefore, the components of early lamellar 
ore sulfide isotope were likely formed under the mixing of the source of sulfide isotopes 
with low values and reduction of seawater sulfate with high values in unequilibrium 
condition. Ohmoto (1983) pointed that reduced seawater sulfate and magmatic sulfur 
were two main sources of sulfur in VMS deposit, and magmatic sulfur could be directly 
derived from magmatic exhalation. Therefore, volcanic magmatic sulfur (δ34S≈0), as the 
end member components with lowδ34 S values, was in consistent with metallogenic 
process and the data that δ34 S value of sulfide samples was between the δ34S values of 
magmatic sulfur and seawater sulfide. The δ34S value (4.32-6.75‰) of lamellar ore 
sulfide was very close to the δ34S value (5.2-7.2 ‰) of “Kuroko-type” VMS deposit 
(Ohmoto, 1983, 1996), which also implied that the source of two sulfurs might have 
similar fractional mechanism. 
Correspondingly, The variation range of δ34S value in hydrothermal vein type sulfide 
was narrow, the distribution interval of -4.37～+3.35‰ was distributed in tower form 
with mean value of ＋0.81‰. The characteristics above showed the characteristics of 
deep source magmatic sulfur (Jochen et al., 2002), which were different from the source 
of lamellar ore sulfide. The δ34S value order of hydrothermal vein ore sulfide doesn’t 
conform to the order in hydrothermal sulfide under fractionation equilibrium condition 
either (Shan et al., 2009), mainly manifested as the relatively low δ34S value of pyrite. It 
should be caused by the multi-stage fractionation of sulfide during the multi-
stage hydrothermal activities (Zhong et al., 2013; Long et al., 2015), conforming to 
existence of multi-stage quartz vein and calcite vein in the field. 
 
Ore-forming fluid source 
Hydrogen oxygen isotopes evidence 
O, H isotope composition of lamellar ore quartz and veined quartz are shown in 
Figure 11a. Two kinds of samples all have similar 18OH2O value (4.37-6.87), while D of 
lamellar quartz is larger than veined quartz. There are mainly two cognitions for the 
source of ore-forming fluids of massive sulfide deposits: seawater generates isotope 
exchange and forms the enriched 18O fluid (Beaty and Taylor, 1982; Barriga and 
Kerrich, 1984), or generates mixture of magmatic water and sea water (Yang and Scott, 
1996; Hou et al., 2001, 2003). The lamellar quartz sample points are near to left side of 
primary magmatic water range, and have the tendency of pointing at seawater