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一般认为,糜棱岩中较大的长石晶体是原生大长石晶体的残余.这些原生大长石晶体粒度的缩减要比基质中晶体粒度的缩减更小.大长石晶体称为残碎斑晶.本文所举实例是苏格兰西北部Eribll湖附近Moine逆冲断层带的糜棱岩中斜长石晶体里复杂的环带现象,这种现象揭示了变形过程中晶体的生长情况,也就是变斑晶的生长情况.该区糜棱岩的原岩是长英质的Lewisian片麻岩,它包含的矿物(以含量多少为序)有石英、斜长石、微斜长石、白云母和绿泥石.以石英和斜长石为主的基质的平均粒度为30μm;而斜长石变斑晶的直径可达200μm;微斜长石直径为50—500μm,在个别的糜棱岩标本中可
It is generally accepted that the larger feldspar crystals in the mylonites are the remnants of the native feldspar crystals.The size reduction of these primary feldspar crystals is smaller than the reduction of the grain size in the matrix.The big feldspar crystals are called " The example here is the complex zonation of plagioclase crystals in the mylonites of the Moine thrust belt near Lake Eribll in northwestern Scotland, which reveals the growth of crystals during deformation, that is, Phytoporphyrotropy The origin of mylonites in this area is feldspathic Lewisian gneiss, which contains minerals (in order of their content) quartz, plagioclase, plagioclase, muscovite And chlorite.The average particle size of the matrix composed mainly of quartz and plagioclase is 30μm, the diameter of plagioclase plagioclase is up to 200μm, the diameter of microcline is 50-500μm, Specimens can be