Qihan Shen provided a review of the text, as follows: Rong and Wang recently released their 162 page-text to the Internet. This text is an atlas, in which the authors stressed the exposition of metasomatic textures and their formation mechanisms than other atlases both at home and abroad. The metasomatism of various minerals, including albite, K-feldspar, muscovite, biotite, quartz, beryl, calcite, apatite, etc., is systematically discussed with clear, colored, microscopic pictures and explanations. As a new attempt and development, the authors advanced both hetero-oriented and co-oriented patterns of mono-mineral replacement in granites. The hetero-oriented replacement pattern includes the albitization and the K-feldspathization occurring at grain boundary of plagioclase with K-feldspar and of two K-feldspars, the muscovitization and biotitization at grain boundary of K-feldspar with mica and of two biotites, etc.
The co-oriented replacement pattern includes mainly the deanorthitization of plagioclase, co-oriented albitization of K-feldspar, co-oriented muscovitization and chloritization of biotite, etc. The classification of mineral replacement reflecting the objective facts is of important significance. The authors elaborated systematically on the formation mechanism of mineral replacement, its genetic hypotheses, the passage for hydrothermal fluids, the replacement mechanism (dissolution-precipitation and ion-exchange), etc.
Myrmekite is the most visible texture in granite. So far there are six genetic hypotheses about its formation mechanism, including nibble replacement.
After quoting extensively to discuss the possibilities and contradictions of the other hypotheses, the authors prove that myrmekite is actually formed from
K-feldspar replaced by Na plus Ca-bearing fluid, forming the replacive plagioclase leaning against a feldspar crystal either plagioclase or K-feldspar.
As the SiO2 content needed to compose replacive plagioclase is less than that contained in the replaced K-feldspar, the surplus SiO2 remaining in situ produces the vermicular quartz grains. The book was drafted by Prof. Jiashu Rong on the basis of ample material collected by all means after his retirement with the encouragement given by Prof. Lorence Collins. Rong hopes that his knowledge and judgement obtained in his study on metasomatic textures in granites reflect the objective situation. However, whether it is a perfect reflection requires practical inspection and extensive review by all experts on the line. There might be different viewpoints about some phenomena for our further discussion and in-depth study before we get a scientific explanation.
The research on metasomatic textures in granites is a supplement for igneous petrography. Moreover, it is of valuable reference to the study of formation mechanism of granite. The senior author hoped that the book would be published as soon as possible, so as to promote an intensive communication and a deeper study on the subjects involved.
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