The types, composition and physico-chemical conditions of primary fluid inclusions were researched. The results show that the primary fluid inclusions contain vapor and liquid phase type （Type I）, daughter mineral-b...The types, composition and physico-chemical conditions of primary fluid inclusions were researched. The results show that the primary fluid inclusions contain vapor and liquid phase type （Type I）, daughter mineral-bearing type （Type II） and pure liquid phase type （Type III）. The compositions of vapor are mainly H20 and CO2 with a tiny amounts of CH4 and H2; the liquid phase mainly contains Mg2＋, Ca2＋, Na＋, K＋, CI- and SO]-, and w（Na＋）/w（K＋）〉l; the homogenization temperatures of the primary fluid inclusions can be divided into 190-250 ℃, 250-340 ℃ and 360-420 ℃, corresponding to the salinities of 4%-9%, 9%-14%, and 14%-20.43% （NaC1 equivalent mass fraction）, respectively. The mineralization process can be divided into three episodes： the silicatization stage, the quartz-sulfide stage, and the carbonatization stage, and all of them are associated with the ore-forming hydrothermal fluid activity. The origin of the hydrothermal fluid is from magrnatic water mainly, and later it mixes with the groundwater and meteoric water, which lead to the decrease of temperature and salinity. The decrease of salinity, temperature and pressure are the main causes of the metallogenic elements unloading and enriching in the favorable position.展开更多
Sipingshan gold deposit is gold-bearing sillcalite in type. There only exist a few kinds of sulfide in the ore and it is lower in content. The gold degree is lower. Au is closely related to the Ag, Cu, Pb, As and Hg e...Sipingshan gold deposit is gold-bearing sillcalite in type. There only exist a few kinds of sulfide in the ore and it is lower in content. The gold degree is lower. Au is closely related to the Ag, Cu, Pb, As and Hg elements. The upper sillealite has Eu and Ce negative anomaly, and the lower sillealite has Eu positive anomaly, however, the hot spring cemented breccia and rhyolite porphyry have Eu negative anomaly; the S isotope component has deep-seated magmatic sulfur and terrestrial sulfate characteristic; and the Ph isotope has the character of the mixture origin of crust and mantle that is mainly dominated by Pb in the orogenic beh. The oreforming tluid temperature is 180℃-244℃ , characterized by magmatie hydrothermal and meteoric water; and the ore-forming age is 87 Ma. The deposit was formed by the metallogenic fluid in the tectonic fault zone overtlowing near the earth＇ s surface and leading to the metallogenic funetion and the metallogenic substar,ee deposition.展开更多
Using Fourier transform infrared spectroscopy(FTIR),we measured water contents in quartz and feldspar for four kinds of felsic rocks,i.e.,undeformed granite,banded granitic gneiss,fine-grained felsic mylonite,and fine...Using Fourier transform infrared spectroscopy(FTIR),we measured water contents in quartz and feldspar for four kinds of felsic rocks,i.e.,undeformed granite,banded granitic gneiss,fine-grained felsic mylonite,and fine-grained quartz-mica schist,collected from Pengguan Complex and Kangding Complex in the Longmenshan tectonic zone,Sichuan,China.The absorbance spectra suggest that water in coarse-grained quartz and feldspar of undeformed granite and banded granitic gneiss occurs mainly as hydroxyl in crystal defects,and water in most of fine-grained quartz and feldspar of felsic mylonite is molecular water in inclusions and liquid-type water in grain boundaries,but in some cases it still occurs as hydroxyl in crystal defects.Water content of quartz in undeformed granite is 0.001 wt%-0.009 wt %,and that of feldspar 0.005 wt%-0.02 wt%.The banded granitic gneiss shows water contents of 0.002 wt%-0.011 wt% in quartz and 0.012 wt%-0.036 wt% in feldspar.Quartz ribbon and feldspar ribbon in fine-grained felsic mylonite show that their water contents are similar to those of coarse-grained quartz and feldspar in granite,0.002 wt%-0.011 wt%,and 0.004 wt%-0.02 wt%,respectively.Water contents of fine-grained quartz and feldspar are respectively 0.004 wt%-0.02 wt% and 0.012 wt%-0.06 wt%.Water content of quartz in fine-grained quartz-mica schist is 0.007 wt%-0.15 wt%.Water-bearing minerals display much higher water contents than those of nominally anhydrous minerals,and the percentage of water-bearing minerals in felsic rocks increases with the strain of rocks.These new data indicate that hydroxyl in crystal defects has basically not been released during the shear deformation,and on the contrary,the increase in molecular water in inclusions and liquid-type water in grain boundaries as well as water-bearing minerals after shear deformation leads to a significant increase of the water content in deformed rocks.Based on data of creep tests,it is inferred here that the fine-grained mylonites with more water have much lower strength than that of the weakly deformed coarse-grained rocks in the middle crust,and this indicates that trace amount of water significantly helped develop the ductile shear zone.展开更多
基金Project(200911007-04) supported by the Special Funds for Scientific Research of Land and Natural Resources, ChinaProject (2007CB411405) supported by the National Basic Research Program of ChinaProject(20109901) supported by the National Crisis Office of China
文摘The types, composition and physico-chemical conditions of primary fluid inclusions were researched. The results show that the primary fluid inclusions contain vapor and liquid phase type （Type I）, daughter mineral-bearing type （Type II） and pure liquid phase type （Type III）. The compositions of vapor are mainly H20 and CO2 with a tiny amounts of CH4 and H2; the liquid phase mainly contains Mg2＋, Ca2＋, Na＋, K＋, CI- and SO]-, and w（Na＋）/w（K＋）〉l; the homogenization temperatures of the primary fluid inclusions can be divided into 190-250 ℃, 250-340 ℃ and 360-420 ℃, corresponding to the salinities of 4%-9%, 9%-14%, and 14%-20.43% （NaC1 equivalent mass fraction）, respectively. The mineralization process can be divided into three episodes： the silicatization stage, the quartz-sulfide stage, and the carbonatization stage, and all of them are associated with the ore-forming hydrothermal fluid activity. The origin of the hydrothermal fluid is from magrnatic water mainly, and later it mixes with the groundwater and meteoric water, which lead to the decrease of temperature and salinity. The decrease of salinity, temperature and pressure are the main causes of the metallogenic elements unloading and enriching in the favorable position.
文摘Sipingshan gold deposit is gold-bearing sillcalite in type. There only exist a few kinds of sulfide in the ore and it is lower in content. The gold degree is lower. Au is closely related to the Ag, Cu, Pb, As and Hg elements. The upper sillealite has Eu and Ce negative anomaly, and the lower sillealite has Eu positive anomaly, however, the hot spring cemented breccia and rhyolite porphyry have Eu negative anomaly; the S isotope component has deep-seated magmatic sulfur and terrestrial sulfate characteristic; and the Ph isotope has the character of the mixture origin of crust and mantle that is mainly dominated by Pb in the orogenic beh. The oreforming tluid temperature is 180℃-244℃ , characterized by magmatie hydrothermal and meteoric water; and the ore-forming age is 87 Ma. The deposit was formed by the metallogenic fluid in the tectonic fault zone overtlowing near the earth＇ s surface and leading to the metallogenic funetion and the metallogenic substar,ee deposition.
基金supported by National Natural Science Foundation of China(Grant No.40972146)State Key Laboratory of Earthquake Dynamics(Grant Nos. LED2009A01,LED2008A03)
文摘Using Fourier transform infrared spectroscopy(FTIR),we measured water contents in quartz and feldspar for four kinds of felsic rocks,i.e.,undeformed granite,banded granitic gneiss,fine-grained felsic mylonite,and fine-grained quartz-mica schist,collected from Pengguan Complex and Kangding Complex in the Longmenshan tectonic zone,Sichuan,China.The absorbance spectra suggest that water in coarse-grained quartz and feldspar of undeformed granite and banded granitic gneiss occurs mainly as hydroxyl in crystal defects,and water in most of fine-grained quartz and feldspar of felsic mylonite is molecular water in inclusions and liquid-type water in grain boundaries,but in some cases it still occurs as hydroxyl in crystal defects.Water content of quartz in undeformed granite is 0.001 wt%-0.009 wt %,and that of feldspar 0.005 wt%-0.02 wt%.The banded granitic gneiss shows water contents of 0.002 wt%-0.011 wt% in quartz and 0.012 wt%-0.036 wt% in feldspar.Quartz ribbon and feldspar ribbon in fine-grained felsic mylonite show that their water contents are similar to those of coarse-grained quartz and feldspar in granite,0.002 wt%-0.011 wt%,and 0.004 wt%-0.02 wt%,respectively.Water contents of fine-grained quartz and feldspar are respectively 0.004 wt%-0.02 wt% and 0.012 wt%-0.06 wt%.Water content of quartz in fine-grained quartz-mica schist is 0.007 wt%-0.15 wt%.Water-bearing minerals display much higher water contents than those of nominally anhydrous minerals,and the percentage of water-bearing minerals in felsic rocks increases with the strain of rocks.These new data indicate that hydroxyl in crystal defects has basically not been released during the shear deformation,and on the contrary,the increase in molecular water in inclusions and liquid-type water in grain boundaries as well as water-bearing minerals after shear deformation leads to a significant increase of the water content in deformed rocks.Based on data of creep tests,it is inferred here that the fine-grained mylonites with more water have much lower strength than that of the weakly deformed coarse-grained rocks in the middle crust,and this indicates that trace amount of water significantly helped develop the ductile shear zone.
