Abstract:The hypothesis of "transportation zonation due to concentration differences of mineral particles" for vein type tungsten deposits holds mainly that the ore-forming materials, in the form of mineral particles 10-3~10-7 cm in size, are transported and then precipitated in the Jaminar metallogenic fluids, and that the distance of transportation is affected by the initial concentration differences of different mineral particles, i.e., those with high concentration are transported for a relatively short distance and precipitated earlier, while those with low concentration travel for a comparatively long distance and are separated out late. The author considers that ore-forming materials for vein type tungsten deposits of South China are mainly derived from granitic magma. It is quite impossible for wolframite and cassiterite to be moved to the ore-hosting fractures in the form of mineral particles in that they are hardly able to pass through the capillary holes which are equivalent to these particles in size. The field of flowing metallogenic fluids is a relatively closed fracture system with complicated geometric configuration, and during the ore-forming process, pressure, temperature and such properties of ore-forming fluids as viscosity, density and flow speed vary continuously. It is therefore conceivable that the Leiruo number of the ore-forming flowage is not a constant and that the flowage, in addition to the form of laminar flow, is characterized by local and overall evolutional variations whose process might be in the order of torrent-laminar flow-motionless. Wolframite partkles are considerably different from the media in density, and the laminar flow is unable to move the mineral particles on. Therefore, wolframite and other metallic minerals are crystallized out instead of being formed through accumulation of mineral particles carried by laminar flow as a result of collision with walls. The concentration difference theory defines the concentration as number of identically-sized mineral particles in unit volume of initial hydrothermal fluids. This definition is scientifically unacceptable, because no mineral particles occur in initial hydrothermal fluids, and hence the transportation zonation due to concentration differences of mineral particles derived from this definition is inconsistent with the practical situation of vein type tungsten deposits. It is obvious that the four component parts (mineral particles, Jaminar flow, concentration differences and transportation) making up the theory of transportation zonation due to concentration differences of mineral particles are not established on the solid theoretical and practical ground. This theory even has many methodological doubts. The author thus feels sure that the so-called "transportation zonation due to concentration differences of mineral particles” will be completely discarded.
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陈尊达.1986.略论脉钨矿床“矿物微粒浓差运离分带理论”之不能成立[J].矿床地质,5(2):45~52.1986.On The Untenability Of The Theory Of "Transportation Zonation Due To Concentration Differences Of Mineral Particles" For Vein Type Tungsten Deposit[J].Mineral Deposits5(2):45~52
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