| 攀西地区白马和红格层状岩体分异特征的数学地质论证 |
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| 引用本文：.1984.Geomathematic Evidence For The Differentiation Nature Of The Baima And Hongge Layered Intrusive Bodies In Panxi Area, Sichuan Province[J].Mineral Deposits,3(3):67~75 |
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| Geomathematic Evidence For The Differentiation Nature Of The Baima And Hongge Layered Intrusive Bodies In Panxi Area, Sichuan Province |
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| Abstract:The vanadium-bearing titanomagnetite deposits in Panxi area are gigantic in size, and there have been mainly two different hypotheses on the origin of ore-bearing basic-ultrabasic masses and the metallogenic mechanism. Some geologists argue for the magmatic crystallization differentiation —igneous accumulation, whereas others favor the injection of late magma. It is reasonable to suppose that the former argument should be supported by systematic variations in petrochemical compositions and some other parameters in downward succession, and that no such variations might be observed if the latter claim could hold water. In order to seek a solution to these disputes, the authors have made some statistical calculations in such aspects as spatial distribution of chemical elements and mi7ierals, variation regularity of rock-forming temperatures and oxygen fugacities, and the relations between distance of sample from the top of the major ore bed and the chemical com position. The resulting data show the presence of a close connection between the sequence of accumulation of elements in the rock masses and the weight of those elements: in spatial distribution, heavy elements and minerals are concentrated in lower portion and light ones in upper portion rock-forming temperatures and fugacities decrease progressively from the bottom upward; chemical compositions of the rock masses also show systematic variations in upward direction with the gradual increase in acidities and the gradual decrease in basicities and ore-forming constituents such as TFe, TiO2, V2O5 and Cr2O3. In addition to these overall regular variations, the rock masses exhibit evidently three huge accumulation cycles with the boundaries in accordance with what has been recorded in the field. Spatial distribution of elements and minerals in each cycle resembles their overall distribution in the whole rock mass. Gravity has caused the concentration of heavier elements, such as iron, titanium and vanadium, in the lower part of each cycle to form ores. An investigation into the Baima, Xingjie and Batoushang intrusive masses shows that perfect differentiation, well-developed layered structure and the action of gravity are all factors favorable for ore deposition. All these phenomena point to the characteristics of geologic bodies produced by crystallization differentiation and action of gravity during the cooling of magma. Rhythmic cycle might have been the result of the intermittent supply of some cognate materials prior to the cooling and consolidation of the magma. The Baima and Hongge basic-ultrabasic rock masses and the vanadium -bearing titanomagnetite deposits contained in them are hence products of magmatic crystallization differentiation-igneous accumulation. |
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