He W.,China University of Geosciences |
Yu X.,China University of Geosciences |
Mo X.,China University of Geosciences |
He Z.,Yunnan Geology and Mineral Resources Co. |
And 3 more authors.
Acta Petrologica Sinica | Year: 2012
The Beiya gold-polymetallic ore field is one of the typical deposits related to the Jinshajiang-Ailaoshan alkali-rich intrusion of the Cenozoic Period, and it is also a magmatic-hydrothermal metallogenesis system related to alkali-rich intrusion during the Himalaya epoch. Based on the recent extensive researches and field investigations, this article systematically studies and concludes the genetic of various ore types, the relationship between mineralization, alkali-rich porphyries and the genesis of iron ore. In the ore field, four types of gold-polymetallic deposits have been recognized, there are porphyry-type Cu-Au mineralization, skarn-type Fe-Au-Cu-Pb-Zn mineralization, breccia-type Fe-Au-Pb-Zn deposits and hydrothermal Au-Ag-Pb-Zn mineralization in wallrock. Among the fours type of gold-polymetallic deposits, skarn and hydrothermal type are the most important metallogenesis. The whole-rock geochemical dating of quartz syenite porphyry shows that it belongs to potassic alkali-rock. And the LA-ICP-MS U-Pb age are defined as sample WDS-1 (31.5 ±1. 1 Ma), sample HNT-1 (31.34 ±0.73 Ma). The quartz syenite porphyry which is shoshonitic series, not only provides a rising force and heat, but also acts as the main source and carrier for the ore-forming material and mineralization fluid. As a result, it builds a porphyry body-centered continuous porphyry-hydrothermal system, which is made of porphyry-type, skarn-type, hydrothermaltype, and various weathered-sedimentary-type deposits. The progress of forming the quartz syenite porphyry and ores was accompanied by the strong magmatic activity in the Sanjiang metallogenic belt, and the crust-mantle reaction made an important contribution to the mineralization and diagenesis in Beiya area. A large number of iron ore are produced along the contact between the alkali-rich porphyry and surrounding rock. It is found that the native iron ore accounts for 30. 08% of magnetite and siderite accounts for 24. 68%. Most of the magnetites which assume tabular forms and polysynthetic twin are the illusion of hematite. According to research, magnetite and siderite is the metasomatism product of the iron-bearing skarn in the alkaline environment. When the H + concentration in Hydrothermal is decreases, hematite will be reduced to magnetite. It is the illusion of hematite when magnetite retains the crystal forms of hematite. The analyses show that the ore-forming fluids and the skarn mineralization last for a long time, which may be one the most important reason for the accumulation of that abundant metal.
He W.Y.,China University of Geosciences |
Mo X.X.,China University of Geosciences |
Yu X.H.,China University of Geosciences |
He Z.H.,Yunnan Geology and Mineral Resources Co. |
And 4 more authors.
Acta Petrologica Sinica | Year: 2013
The Beiya gold-polymetallic deposit lies in the middle of the Cenozoic Jinshajiang-Ailaoshan alkali-rich intrusion belt in the western Yunnan Province. It is a representative ore deposit in studying Himalaya epoch mineralization and shows bright future for further prospecting. The first highly precise dating of the rock-forming and mineralization in Beiya gold-polymetallic deposit is provided in this paper. The U-Pb LA-ICP-MS dating of the zircon from Hongnitang quartz syenite porphyry yields an age of 36. 48 ± 0. 26Ma. Re-Os dating of molybdenite separated from the skarn ore bodies gives a model age of 36. 87 ± 0. 76Ma. These ages suggest that the mineralization in the Beiya gold-polymetallic deposit is genetically associated to the quartz syenite porphyry. The Re contents of molybdenite indicate that the ore-forming materials are derived from mantle and crust. Based on the same ages of the rock-forming and mineralization in Beiya gold-polymetallic deposit and other deposits in jingshajiang-Ailaoshan metallogenic belt, it is proposed that these deposits all occurred under the background of India-Eurasia collision when the tectonic regime changing make the thickened lower crust and upper mantle melt partially.
Resources prediction geo-chemical method in deep area for old orefield-a case study of Chengmenshan copper deposit about copper deep area resources prediction, Jiujiang County, Jiangxi Province, China
Gong P.,Hubei University |
Gong M.,Hubei University |
Xiong R.,Hubei University |
Zhao B.,Hubei University |
And 6 more authors.
Geological Bulletin of China | Year: 2010
In order to improve resource base and guarantee long-term development for old mines, resources predicting and calculating for deep area are imperative under current situation. This paper has researched into Chengmenshan copper (Cu) deposit about Cu deep resources prediction, Firstly certain Cu-enriched geological body has been selected as research target, then by applying fitted function and three-dimension (3D) geological visualization modeling, principles and detailed process by means of integral planar metal quantity and 3D geological body block method are discussed. Two methods has been managed to calculate resources in the range from 0m to -500 m (the first space range) and -500 m to -1000 m (the second space range) in depth respectively. Both of them are feasible for the first space and the results are quite similar compared with the results by traditional method, while 3D block method is preferable for the second space. In conclusion, when the ore cut-off grade index is 0.3% and 0.2% respectively, by using the second method, corresponding results are 57.970×104t and 137.580×104t; besides, deep resources are mainly concentrated in layer-like Cu-enriched pyrite (namely No. I ore body).