摘要
矿物线理 这里还必须弄清早期火成线状排列与晚期构造发育之间的差异。 第一种矿物优选方位与析离体的形成及粘流有关。云母和钾长石巨晶产在析离体中或之上,并与之平行。 第二种矿物线理与其赋存的片理有关。其倾角一般很陡。
A mechanism leading to the zonation of granitic batholiths is proposed.Fundamentally, it is based on the common occurrence of mafic enclavesnear the margins of plutons, on the realization that these enclaves were ina magmatic condition at time of incorporation, and on the observation thatthey very often play an essential role in the formation of schlieren. Thelatter represent the shearing through convection of these blobs of maficmagma within the rising, and evolving pluton, which leads to progressivedispersal of the mafic material inwards until a threshold in temperatureand viscosity is reached. This type of zonation, which does not excludeothers, nor the simultaneous combination of several mechanisms of differen-tiation, would therefore be due to the mixing of two contrasted magmas,the mafic one, in the case of normal zonation, being injected marginally toform a failed ring-dyke. The two liquids may be derived from distinctsources, with far-reaching consequences.
关键词
花岗质
深成岩体
分带性
岩墙
granitoids
plutons
hybrids
convection / zoned batholiths
enclaves
schlieren
magma mixing
ring-dykes
