The geological investigation of the Dachang ore field was carried out in detail, and the geological characteristics of the deposits, consisting of the Tongkeng and Dafulou deposits, were observed and researched system...The geological investigation of the Dachang ore field was carried out in detail, and the geological characteristics of the deposits, consisting of the Tongkeng and Dafulou deposits, were observed and researched systematically. It suggests that the mineralization types of Changpo ore are composed of cracking vein, thin vein, bedded vein and thin vein-net vein disseminated types. The cracking vein ore is usually lens-shaped in the vertical direction. The thin vein ore is always characterized by a stable trend and tendency. The bedded ore always occurs along the strata in the way of filling and metasomatism in the fracture system. In terms of Bali-longtoushan ore, it is characterized by complicated mineral components and a variety of minerals. More generally, ore textures consist of the anhedral-subhedral shapes and thin particle, and secondary with the interstitial texture, solid solution separation texture, dissolution texture, corona texture, and crushing texture, yet ore structures include the massive, veinlet, disseminated, banded, miarolitic, biological residual and brecciated structure. In addition, the sulfur isotopes of the metal sulfide were analyzed. The results show that the δ34S values of Tongkeng ore range from-0.30% to 1.38% with more dispersed characteristics, yet in terms of Dafulou ore, the δ34S values are from-0.15% to 0.22% which are characterized by more focused. This indicates that the sulfur isotope composition has large difference between the different deposits. The sulfur isotope values of the Dafulou ore are concentrated relatively, yet are dispersed for the Tongkeng ore. Likewise, there are also divergences of sulfur isotopes for the different minerals. The sulfur isotope values of pyrrhotine are dispersed, yet are homogeneous for pyrite. In short, the divergence of the sulfur isotope is reflected in both the different deposits and minerals, all of these may account for the difference of sulfur sources.展开更多
For revealing the ore sources of the Dachang tin?polymetallic ore deposit, the lead isotopes were analyzed systematically by using the single minerals of sulphides, including pyrite, pyrrhotite, sphalerite, and galena...For revealing the ore sources of the Dachang tin?polymetallic ore deposit, the lead isotopes were analyzed systematically by using the single minerals of sulphides, including pyrite, pyrrhotite, sphalerite, and galena. Then, the mineral sources and their characteristics were discussed based on the classical lead isotope discriminating model. The results show that the lead isotope ratios of206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb range from 17.478 to 18.638, 15.440 to 15.858, and 37.556 to 39.501, respectively. According to Zartman lead model, the ore lead contains the upper crust composition; however, the granite does not provide all ore leads, and other material sources exist. Obviously, the ore deposit belongs to the result of the combined effect of crust?mantle. The source rocks are characterized by a certain degree of similarity with the island arc material. Moreover, its distant origin in the upper and lower crusts may be related to the subduction island arc material or oceanic crust. The mantle-derived material may have a certain status in the source region. Meanwhile, based on the lead isotope three-dimensional topology projection vectors, the ore leads are concentrated in zoneA, which indicates the characteristics of Yangtze lead isotope province and a possible genetic relationship with Yangtze block.展开更多
The Qujiashan manganese deposit is located in the Longmen-Daba fold belt along the northern margin of the Yangtze Block. The layered ore bodies are distributed within the purple-red calcareous shale. Qujiashan is a hi...The Qujiashan manganese deposit is located in the Longmen-Daba fold belt along the northern margin of the Yangtze Block. The layered ore bodies are distributed within the purple-red calcareous shale. Qujiashan is a high-grade w(MnO)=8.92% to 18.76%) manganese deposit with low-phosphorus w(P2O5)=0.08% to 0.16%) content. It also has a low total REEs contents(with an average of 101.3×10-6), and has inconspicuous Ce(0.81 to 1.29) and Eu(1.00 to 1.25) anomalies. lg(Ce/Ce*) values are from-0.02 to 0.11. The ores have high SiO2/Al2O3 and Al/(Al + Fe + Mn) ratios. In figures of Fe–Mn–[(Ni+Cu+Co)×10] and lgU–lgTh, all samples show that hydrothermal exhalative fluids played an important role during mineralisation. The δ13CPDB and δ18OSMOW values of eight ore samples are from-20.7‰ to-8.2‰(with an average of-12.4‰) and from 14.3‰ to 18.7‰(with an average of 17.0‰), respectively. These carbon and oxygen isotopic features indicate that hydrothermal fluids derived from deep earth are participation in the metallogenic process, which is also supported by high paleo-seawater temperatures varying from 47.08 to 73.98 °C. Therefore, the geological and geochemical evidences show that the Qujiashan deposit formed from submarine exhalative hydrothermal sedimentation.展开更多
基金Project(41202051)supported by the National Natural Science Foundation of ChinaProject(2012M521721)supported by China Postdoctoral Science FoundationProject(CSUZC2013021)supported by the Open-End Fund for the Valuable and Precision Instruments of Central South University,China
文摘The geological investigation of the Dachang ore field was carried out in detail, and the geological characteristics of the deposits, consisting of the Tongkeng and Dafulou deposits, were observed and researched systematically. It suggests that the mineralization types of Changpo ore are composed of cracking vein, thin vein, bedded vein and thin vein-net vein disseminated types. The cracking vein ore is usually lens-shaped in the vertical direction. The thin vein ore is always characterized by a stable trend and tendency. The bedded ore always occurs along the strata in the way of filling and metasomatism in the fracture system. In terms of Bali-longtoushan ore, it is characterized by complicated mineral components and a variety of minerals. More generally, ore textures consist of the anhedral-subhedral shapes and thin particle, and secondary with the interstitial texture, solid solution separation texture, dissolution texture, corona texture, and crushing texture, yet ore structures include the massive, veinlet, disseminated, banded, miarolitic, biological residual and brecciated structure. In addition, the sulfur isotopes of the metal sulfide were analyzed. The results show that the δ34S values of Tongkeng ore range from-0.30% to 1.38% with more dispersed characteristics, yet in terms of Dafulou ore, the δ34S values are from-0.15% to 0.22% which are characterized by more focused. This indicates that the sulfur isotope composition has large difference between the different deposits. The sulfur isotope values of the Dafulou ore are concentrated relatively, yet are dispersed for the Tongkeng ore. Likewise, there are also divergences of sulfur isotopes for the different minerals. The sulfur isotope values of pyrrhotine are dispersed, yet are homogeneous for pyrite. In short, the divergence of the sulfur isotope is reflected in both the different deposits and minerals, all of these may account for the difference of sulfur sources.
基金Project(41202051)supported by the National Natural Science Foundation of ChinaProject(S2014GK3005)supported by Hunan Industrial Science and Technology Support Program+1 种基金Project(2012M521721)supported by China Postdoctoral Science FoundationProject(CSUZC2013021)supported by the Open-end Fund for the Valuable and Precision Instruments of Central South University,China
文摘For revealing the ore sources of the Dachang tin?polymetallic ore deposit, the lead isotopes were analyzed systematically by using the single minerals of sulphides, including pyrite, pyrrhotite, sphalerite, and galena. Then, the mineral sources and their characteristics were discussed based on the classical lead isotope discriminating model. The results show that the lead isotope ratios of206Pb/204Pb,207Pb/204Pb, and208Pb/204Pb range from 17.478 to 18.638, 15.440 to 15.858, and 37.556 to 39.501, respectively. According to Zartman lead model, the ore lead contains the upper crust composition; however, the granite does not provide all ore leads, and other material sources exist. Obviously, the ore deposit belongs to the result of the combined effect of crust?mantle. The source rocks are characterized by a certain degree of similarity with the island arc material. Moreover, its distant origin in the upper and lower crusts may be related to the subduction island arc material or oceanic crust. The mantle-derived material may have a certain status in the source region. Meanwhile, based on the lead isotope three-dimensional topology projection vectors, the ore leads are concentrated in zoneA, which indicates the characteristics of Yangtze lead isotope province and a possible genetic relationship with Yangtze block.
基金Project(41663006)supported by the National Natural Science Foundation of ChinaProject(1212011220725)supported by the Geological Survey Project of the China Geological Survey
文摘The Qujiashan manganese deposit is located in the Longmen-Daba fold belt along the northern margin of the Yangtze Block. The layered ore bodies are distributed within the purple-red calcareous shale. Qujiashan is a high-grade w(MnO)=8.92% to 18.76%) manganese deposit with low-phosphorus w(P2O5)=0.08% to 0.16%) content. It also has a low total REEs contents(with an average of 101.3×10-6), and has inconspicuous Ce(0.81 to 1.29) and Eu(1.00 to 1.25) anomalies. lg(Ce/Ce*) values are from-0.02 to 0.11. The ores have high SiO2/Al2O3 and Al/(Al + Fe + Mn) ratios. In figures of Fe–Mn–[(Ni+Cu+Co)×10] and lgU–lgTh, all samples show that hydrothermal exhalative fluids played an important role during mineralisation. The δ13CPDB and δ18OSMOW values of eight ore samples are from-20.7‰ to-8.2‰(with an average of-12.4‰) and from 14.3‰ to 18.7‰(with an average of 17.0‰), respectively. These carbon and oxygen isotopic features indicate that hydrothermal fluids derived from deep earth are participation in the metallogenic process, which is also supported by high paleo-seawater temperatures varying from 47.08 to 73.98 °C. Therefore, the geological and geochemical evidences show that the Qujiashan deposit formed from submarine exhalative hydrothermal sedimentation.
