| 评流行的岩浆热液成矿理论 |
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| 引用本文： | 张,旗.评流行的岩浆热液成矿理论[J].甘肃地质学报,2012(4):1-14. |
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| 作者姓名： | 张 旗 |
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| 作者单位： | 中国科学院地质与地球物理研究所，北京 100029 |
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| 基金项目： | 国家自然科学基金重大研究计划（91014001，90714007和90714011）项目资助的研究 |
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| 摘 要： | 流行的岩浆热液成矿理论认为，热液流体和成矿金属源于岩浆，岩浆能够分异和演化，在岩浆分异的晚期，热液达到过饱和而出溶，热液成矿在岩浆后期或期后，岩浆与热液矿床在空间上、时间上和成因上密切相关。笔者认为，上述成矿理论存在许多问题：首先，下地壳是缺水的，下地壳含水量大概不会超过1%，因此，花岗质岩浆是在缺水的条件下部分熔融的，富水条件下的熔融很少，花岗岩也很少是富水的。其次，花岗质岩浆黏性大，它既不能分离结晶也不可能演化。第三，当温度压力下降岩浆固结时，水大多以（OH）的形式进入造岩矿物，几乎没有多少自由水（游离水）被分离出来，野外也没有这样的证据。含矿热液主要来源于下地壳，只要有足够的热，下地壳变质岩中含结构水的矿物即可发生脱水反应释放出水。由于变质岩脱水熔融的温度低于花岗岩部分熔融的温度，因此，脱水熔融可以出现在花岗岩部分熔融之前，熔融的范围也远大于岩浆熔融范围。热液是以自由水的形式出现的，可以在下地壳内循环，富集成矿金属元素。花岗质岩浆部分熔融时也可以包含热液和成矿金属元素，这是毋庸置疑的，至于它是否各类岩浆热液矿床成矿金属的主要来源则是需要讨论的。笔者认为，流行的岩浆热液成矿理论只是一个猜想，与下地壳内发生的情况相去甚远，还不能算是成熟的理论。但是，不排除在花岗岩含水异常丰富的特殊情况下，该理论还有适用的部分。总之，流行的岩浆热液成矿理论不具有普遍的意义。
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| 关 键 词： | 岩浆 热液 水 下地壳 成矿理论 花岗岩 评论 |
Comment on the Popular Magmatic Hydrothermal Mineralization Theory |
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| ZHANG Qi.Comment on the Popular Magmatic Hydrothermal Mineralization Theory[J].Acta Geologica Gansu,2012(4):1-14. |
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| Authors: | ZHANG Qi |
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| Abstract: | The popular magmatic hydrothermal metallogenic theory assumed that hydrothermal and ore-bearing metal are produced from the magma by differentiation and evolution. In the late magmatic differentiation, hydrothermal can be soluble after reaching oversaturation and hydrothermal mineralization are taken place in the deuteric stage or postmagmatic stage. The magma and hydrothermal deposits are closely related in space, time and genesis. The author thinks that the theory has many problems. First of all, the lower crust is lack of water, the water content of the lower crust is probably not more than 1%, therefore, the partial melting of the granitic magma is probably produced under the condition of lack water rather than rich water, and the granite is rarely rich water. Secondly, the granitic magma cannot differentiated and evolved because of the high viscosity. Thirdly, when magma consolidation the temperature and pressure decrease, most of the water in the form of (OH) into rock-forming minerals, almost no much free water is isolated, also no such evidence found in field. The ore hydrothermal mainly comes from the lower crust. As long as there is enough heat, lower crust metamorphic rocks with the structure water mineral can happen dehydration melting. The temperature of dehydration melting is lower than that of partial melting of granitic magma, so the dehydration melting can happen earlier and the melting range is bigger. Hydrothermal in the form of free water is produced and circulated in the lower crust, and it also can enrich ore-bearing metal elements. Granitic magma can also include hydrothermal and ore-bearing metal elements when partial melting happens, as to whether it is the main source of all kinds of magmatic hydrothermal deposit metal elements is the matter that needs to discuss. What the lower crust inside happened is very different. Therefore, the popular magmatic hydrothermal metallogenic theory is just a conjecture, cannot be a mature theory. But, do not eliminate the special circumstances such as the granite is abnormal rich water, this theory is applicable. Anyway, the theory does not have universal significance. |
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