@article{oai:nagoya.repo.nii.ac.jp:00001444, author = {ZEN, Ja Hu and SUWA, Kanenori}, journal = {The Journal of earth and planetary sciences, Nagoya University}, month = {}, note = {Autoclastic rocks are produced in a shallow-level subvolcanic setting by cryptoexplosive activity. In many localities around southeastern China, autoclastic subvolcanic rocks were formed between the late Jurassic and the early Cretaceous. In the Tonglu volcanic basin, three comagmatic stages of volcanic rock have been exposed by deep denudation. First stage rocks consist of rhyolites and rhyodacites and are distributed along the margins of the basin. Third stage hypabyssal intrusions consist of aegirine-riebeckite bearing quartz monzonitic porphyry, and occupy the central basin. Between these stages, autoclastic adamellite porphyry occurs, a subvolcanic rock with porphyritic texture. Autoclastic adamellite porphyry contains "pearlitic" overgrowths around orthoclase phenocryst. The overgrowths contain quartz intergrown with orthoclase that is optically continuous with the host phenocrysts. Pearlitic overgrowths also occur around porphyritic plagioclase, quartz and hornblende. Overgrowths around plagioclase contain mostly plagioclase or orthoclase, with lesser quartz. Overgrowths around quartz phenocrysts are predominantly quartz, with lesser amounts of orthoclase. Overgrowths around hornblende phenocrysts are mostly composed of hornblende with lesser quartz and orthoclase. In general, the pearlitic overgrowths have compositions that are intermediate between the phenocrysts and the groundmass. The overgrowths may therefore represent reaction textures that developed in an autoclastic environment., 国立情報学研究所で電子化したコンテンツを使用している。}, pages = {31--43}, title = {Autoclastic subvolcanic rocks in the Tonglu basin, Zhejiang Province, China : a description of "pearlitic border" textures in an adamellite porphyry}, volume = {49}, year = {2002} }