| 玉龙某些中酸性侵入岩和火山杂岩中的熔融和流体包裹体 |
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| 引用本文：李荫清.1984.玉龙某些中酸性侵入岩和火山杂岩中的熔融和流体包裹体[J].地球学报,6(1):85-106. |
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| 中文摘要:<正> 玉龙铜(钼)矿带地处西藏东部,其大地构造单元属三江褶皱系金沙江优地槽褶皱带的青泥洞—海通复背斜带。区内发育有觉拥—德钦大断裂,构造线呈北西—南东向展布。沿觉拥—德钦大断裂带西侧分布有不同时代的侵入岩和火山杂岩。其中部分二长花岗斑岩体强烈蚀变,发育铜(钼)矿化,构成北南长约200公里、东西宽约70公里、闻名于世的玉龙斑岩铜(钼)矿带(图1)。 |
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| MELT AND FLUID INCLUSIONS IN SOME INTERMEDIATE-ACIDIC INTRUSIONS AND VOLCANIC COMPLEX IN THE YULONG COPPER (MOLYBDENUM) BELT |
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| Abstract:Rhyolites and monzonitic granite porphyries in the Yulong Copper (molybdenum) Belt contain melt inclusions of various types. Most of them are simple glass inclusions which consist of bubbles and glass, but some of them are poly-phasic glass inclusions which contain in addition such daughter minerals as Ti-biotite, titaniferous magnetite, zircon and aptite, or are crystalline melt inclusions which consist of crystalline materials and bubbles, or are devitrified glass inclusions which are derived from recrystallized glass. These melt inclusions are commonly developed in rhyolites, but relatively less in monzonitic granite porphyries, and even less in ore-bearing monzonitic granite porphyries that only contain a few crystalline melt and devitrified glass inclusions. However, the discovery of glass inclusions containing liquid (water) in quartz phenocrysts of barrent monzonitic granite porphyries is very important to the study of the physico-chemical condition of magmatic solidus. Homogenization temperatures of rnelt inclusions are estimated by means of heating-stage and quenching methods as 1000-1300℃ in rhyolites and 900-1150℃ in monzonitic granite porphyries. Because the sluggishness of solid materials would cause the inaccuracy, the duration of constant temperature for their homogenization temperature measurement must be kept for 4-24 hours. In order to reduce inaccuracy, it is better to measure smaller glass inclusions.The composition of glass and daughter minerals of melt inclusions was determined by the electron microprobe. The result shows that the mean composition of the primary magmas of rocks in this region is as follows: SiO2 63.10%, Al2O3 14.09%, TiO2 3.22%, FeO + Fe2O3 6.77%, MnO 0.09%, MgO 3.29%,CaO 0.40%,Na2O 1.16%, K2O 5.69%, and that they contain more TiO2 and MgO than the partial melt magmas from the sial do.These igneous rocks are rich in fluid inclusions, and especially in the ore-bearing monzonitic granite porphyries (and in the barrent porphyries near ore bodies), gaseous and liquid inclusions often coexist with high-saline inclusions which contain various daughter minerals. All of these indicates that copper (molybdenm) mineralization in this region resulted from repeated boiling of ore-bearing hydro thermal fluid. |
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