摘要
在中国东部的中生代断陷盆地中经常有大量次火山花岗斑岩类与陆相的中酸性火山岩共生,有时并与浅成侵入体共同构成火山侵入杂岩。其中有些次火山花岗斑岩的产状和结构比较特殊,对其成因有过长时间的激烈争论。
There is an autoclastic monzonitic granite-porphyry in the Tonglu volcanic basin of Zhejiang province. This rock has intruded into the boundary fault on the southern margin of the basin as an akmolith or stretches along the fault of central basin floor. There is a trasitional relation between it and the outside rhyodacitic rocks with same chemical composition. This rock exhibits the mortar texture. In its matrix, the characteristic texture of acidic hypabyssal rocks is seen to be common. As an outstanding feature, the rock without exception shows the peculiar "pearlitic edge" grown around the margin of crystalloclastic potash feldspars and it may be taken as a texture sign indicated that this rock has been crystallized under superepizonal environment. The structural state of these potash feldspars possesses the character of both volcanic and subvolcanic rocks. The chemical compositions of biobite and hornblende state clearly that the formation temperature of autoclastic monzonitic granite-por -phyry is lower than that of rhyodacitic volcanic rocks but formation pressure of the former is higher than the latter. Therefore it is a special variety of subvolcanic rock and was formed under the overlying strata of volcanic rocks or the extrusive phase and near the conduit of the magmas. This subvolcanic rock often occur in the composite caldere and in the volcanic dome inside the fault depression basin.
作者
王德滋
周金城
刘昌实
陈克荣
周新民
薛纪越
楚雪君
曾加湖
Wang Dezi;Zhou Jincheng;Liu Changshi;Chen Kerong;Zhou Xinmin;Xue Jiyue;Chu Xuejun;Zen Jiahu
出处
《岩矿测试》
CAS
1982年第3期15-24,I0002,共11页
Rock and Mineral Analysis