Tests Of Homogenization Temperature And Volatile Content Of Melt Inclusions

Melt inclusion is droplet of natural magma captured in the process of mineral growth which is the ideal specimen in the research on magmatic evolution. The research on the content of the volatile in the magma is significant to understand the magmatic evolution and ore-forming process. This paper reviews the research progress of the volatile in the melt inclusion in recent years, and employing high temperature mi-crothermometry, electron probe and Raman spectrum tests the homogenization temperature and water content of melt inclusion contained in quartz phenocrysts sampled from Qiushuwan porphyry Mo-Cu deposit in Henan, Caijiaying Pb-Zn deposit and Xiaosigou porphyry Cu-Mo deposit in Hebei. The lithofacies observation shows: the melt inclusions in Caijiaying Pb-Zn deposit are developmental, most of them are crystalline melt inclusions and melt inclusion bearing bubble is rare; the melt inclusions in Qishuwan porphyry Mo-Cu deposit and Xiaosigou porphyry Cu-Mo deposit are poor and most of them are crystalline melt inclusions, among which there are melt-fluid inclusions in Xiaosigou porphyry Cu-Mo deposit. High temperature microthermometry experiment obtain that: the capture temperature of the melt inclusions in Qishuwan porphyry Mo-Cu deposit is 1100℃and formed in the process of in-situ immiscibility after the homogeneous magma being captured; the melt inclusions in Xiaosigou porphyry Cu-Mo deposit formed in heterogeneous capture process of the magma in immiscible phase, because when the temperature is 1100℃, the melt inclusion is not homogenization yet. Electron probe analysis indicates that the components of the melt inclusions are different between these three deposits: the component of the melt inclusions in Caijiying Pb-Zn deposit is pollenite-phonolite, the component of the melt inclusions in Xiaosigou porphyry Cu-Mo deposit is trachyte- trachydacite; the component of the melt inclusions in Qishuwan porphyry Mo-Cu deposit is rhyolite. Raman spectrum detect the water contents in the melt inclusion from Caijiaying Pb-Zn deposit, Xiaosigou porphyry Cu-Mo deposit and Qiushuwan porphyry Mo-Cu deposit are 1.20-13.94wt% (average 5.07 wt%), 0.28-7.21wt% (average 1.95wt%) and 0.58-20.85wt% (average 7.27wt%) respectively. 0.58-20.85wt% (average 7.27wt%) respectively. The range of water content coincides with that of acid magma. Therefore, the ore-forming magmas in Caijiaying Pb-Zn deposit, Xiaosigou porphyry Cu-Mo deposit and Qiushuwan porphyry Mo-Cu deposit are medium-acid silicate melt with high water content. According to the impact of water content in magma on intrusion depth, this paper speculate the order of intrusion depth for deep to shallow in these three deposits is: Xiaosigou porphyry Cu-Mo de-posit, Caijiaying Pb-Zn deposit and Qiushuwan porphyry Mo-Cu deposit.