| 花岗质岩石的交代结构构造及其成因意义 |
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| 引用本文：董申葆,贺高品.1987.花岗质岩石的交代结构构造及其成因意义[J].地球学报,9(2):71-82. |
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| 中文摘要:交代结构构造在花岗岩的结构构造中占有重要地位,它们的出现与花岗岩形成过程的挥发组分有关。本文详述了花岗质岩石中主要造岩矿物的各种交代结构构造的特点及其在不同阶段结构变化系列。花岗岩的交代结构可分为二种成因类型。混合交代和岩浆交代类型,二者在交代结构的表现上有所不同,并可形成一系列交代结构演化系列,它们大致与变质作用经混合岩化作用发展成为岩浆结晶作用的阶段相符合,可分为下列几种主要交代结构类型:由变质作用的镶嵌结构变为混合岩化作用的交代镶嵌和镶嵌交代结构并通过片麻交代结构发展成为岩浆交代的半自形交代结构,后 |
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| THE CLASSIFICATION OF METASOMATIC REPLACEMENT FABRICS OF GRANITIC ROCKS AND ITS GENETIC SIGNIFICANCE |
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| Abstract:Metasomatism plays an important role in the formation of granitic rocks, and is generally considered as one of the most important criteria in identifying its migmatic origin. However, metasomatism exists also as an important factor in magmatic ones, although its significance has long been argued.The evidence of metasomatism in granitic rocks is exhibited by the app-earence of corrosion fabrics and replacement of minerals at the expense of old ones as the result of metasomatic alteration of pre-existing metamorphic rocks or earlier products of newly-born magmas in the course of anatexis.There is a marked tendency showing the successive replacement changes of minerals, especially the alkali metasomatism of plagioclase in the course of anatectic formation of granites of various genetic types. Different kinds of replacemenn fabrics of potassium metasomatism with respect to plagioclase have been demonstrated and discussed.As a whole, the replacement fabrics from the migmatization to the initiation of anatextic melts and finally to the emergence of magma may constitute a replacement fabrics series which may be classified as:1 ) Replacement mosaic texture, mostly developed in Migmatic agglomera-tis recrystallzation stage;2 ) Mosaic replacement texture,developed mainly in migmatization stage;3 ) Replacement gneissic texture, mostly developed with the connection of the formation of migmatic granites;4 ) Hypidiomorphic replacement texture, mainly developed in the mag-matic granites of contamination type.It seems that the appearence of metasomatism in granitic rocks is caused by the volatile constituents involved in the anatexitic process. In fact, crustal rocks could be transformed into autochthonous migmatic granites by means of pore fluids; they could be evolved into different types of migtna plutons by the emplacement of volatile-bearing migma either; and if the volatile constituents ane present in the magma system, there may also occur some replacement pheonomenon known as hypidiomorphic replacement texture or replacement Kporphyroblastic texture in granitic batholithes. |
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