The preliminary study of the discrimination of ore-bearing and (ore)-(free) (rocks) in the Chongjiang copper deposit, Xizang
The preliminary study of the discrimination of ore-bearing and (ore)-(free) (rocks) in the Chongjiang copper deposit, Xizang
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发表时间：
2004
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通讯作者：
L. Bo;Liao Guang-ming
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作者：
L. Bo;Liao Guang-ming
西藏崇江铜矿床位于特提斯-喜马拉雅成矿域，被称为世界三大斑岩成矿域之一。在构造上，它位于冈底斯-念青塘拉构造带内冈底斯陆缘火山-岩浆弧的中部。由于含矿侵入岩与含矿围岩的相似性，用宏观检验或常规分析方法很难区分含矿斑岩和游离围岩。本研究采用热释光法和(颗粒)-(尺寸)统计两种分析方法。矿区岩石的热释光曲线既呈单峰分布，又呈双峰分布。矿化主要赋存于单峰状似斑状二长花岗岩中，矿化度越高，热释光总积分强度值越小。此外，高岭岩具有较高的热释光值，高岭化作用往往与成矿作用呈负相关。含矿斑岩的粒度曲线呈韵律变化，而含矿斑岩的粒度曲线呈渐变变化。由此可见，热释光值和石英(粒)粒度统计量均可作为识别成矿的标志。
The Chongjiang copper deposit, Xizang is located in the Tethys-Himalayan metallogenic domain known as one of three metallogenic domains of porphyry in the world. Tectonically, it lies in the middle part of the Gangdise epicontinental volcanic-magmatic arc within the Gangdise-Nyainqentanglha tectonic zone. It is (often) (difficult) to distinguish the (ore)-(bearing) porphyries and (ore)-(free) wall rocks with the aid of macroscopic examination or conventional analysis because of the similarities between (ore)-(bearing) intrusive rocks and (ore)-(free) wall rocks. Two analytical methods of thermoluminescence and (grain)-(size) statistics are used in this study. The thermoluminescence curves for the rocks in the mining district display both the unimodal and bimodal distribution. The mineralization occurs dominantly in the unimodal porphyroid adamellite, and the higher the mineralization degrees, the smaller the total integration intensity values of thermoluminescence. In addition, the gaolinized rocks have much higher values of thermoluminescence, and the gaolinization often has negative correlation with mineralization. The grain-size curves for the (ore)-(bearing) porphyries display rhythemic variation, while those for the (ore)-(free) rocks exhibit gradual changes. It can be seen that both the values of thermoluminescence and quartz (grain)-(size) statistics may be employed as the criteria for the recognition of mineralization.