Types And Analyses Of Inclusions In Quartz

Quartz is the most common mineral in nature,crystal clear of gemstone grade quartz-the interior of crystal usually contains a wide variety of inclusions,crystal inclusions contain rich geochemical information,so the study of the crystal inclusions is very meaningful.In this paper,through the observation of gem microscope,the petrographic observation of fluid inclusions,the temperature measurement of fluid inclusions,the laser Raman spectroscopy of fluid inclusions,the electron probe of rutile solid inclusions and the geochemical characteristics of fluid inclusions,the formation mechanism of fluid inclusions in the crystal and the genesis of the crystal deposits were discussed.The results and conclusions are as follows:The main development of fluid inclusions in hair crystal and green ghost crystal are gas-liquid two-phase inclusions,containing CO₂ inclusions and pure CO₂ inclusions,the size of the inclusions is mostly 10⁵0?m.Laser Raman experiments show that the characteristic peaks of the solid inclusions in the crystal appear at 609cm-1,696cm-1 and 679cm-1,corresponding to the rutile and chlorite.The composition of the fluid inclusions is mainly H₂O and CO₂,out of H₂S and CH₄ gas,indicating the formation of high oxygen fugacity environment.Petrographic studies show that there are two fluid effects in the hair crystal,and there are three fluid interactions in the green ghost crystal.Fluorescence of the fluid inclusions shows that the uniform temperature range of the fluid inclusions in the hair crystal is 130¹90?,and the uniform temperature range of the fluid inclusions in the green ghost crystal is 165³15?.The results show that the salinity of the inclusions in the hair crystal is 15²1%,which belongs to the high salinity fluid.The salinity of the fluid inclusions in the green ghost crystal is 2¹5%,which means a wide range of salinity,the fluid composition is more complex.The gas phase composition in the hair crystal sample is mainly H₂O.The cation of the liquid phase is mainly Na⁺ and the ore-forming system is a low salinity H₂O-NaCl system.The gas composition of the W-type inclusions in the green ghost crystal sample is H₂O,the C-type inclusions are mainly CO₂,and the cation of the liquid phase is mainly Na+,and the ore-forming system is low-salinity H₂O-CO₂-NaCl system.The trace elements of rutile in the crystal sample are determined by electron probe,and the Nb and Cr contents indicate that the source area of rutile is metamorphic mudstone.According to the uniform temperature in the crystal sample,the hair crystal contains two fluids,the green ghost contains three fluids.It is inferred from the fluid inclusions of different periods that the early ore-forming fluids are high-temperature fluids during the crystallization of the green ghost crystal,due to the boiling effect of immiscible fluid,resulting the separation of gas and liquid phase in the crystal and promoting the separation of CO₂ and H₂O,thus forming W-type and C-type two different fluid inclusions,the second phase of ore-forming fluid is the medium temperature fluid,contains a lot of CO₂;The crystallization process of the hair crystal has two stages of saline solution fluid into the system.After crystal crystallization is completed,the tectonic movement causes the crystal to appear lattice defects,where the fluid enters and produces a series of secondary characteristics.The sample crystal deposit is a medium-low temperature low pressure and high salinity hydrothermal type crystal deposit,which is closely related to the multi-stage ore-forming fluid.