电英质火山岩——西藏岩的发现

The Discovery of Tourmalitic Volcanic Rock Xizangite

世界不少斑岩矿床内都发育有隐爆爆破角砾岩筒，其胶结物是电英岩；这些电英质胶结物一直被视为单一电英岩化产物。基于浅凝相岩浆电英岩（佤山岩）的发现，我们设想过自然界存在一类富硼的酸性岩浆（佤山岩浆），可以在浅成—超浅成、地表和良好封闭条件下，分别形成电...

The results of field,petrography,rock chemistry and mineralogy etc.studies show that the so called “tourmalinization explosion breccia' within some explosive pipes,in which there are copper and gold metallization,in the Eastern Xizang porphyry copper ore belt is characterized by primary volcanic subvolcanic texture and structure.Based on chemical and rock forming mineral composition,if we disregarded the breccias(or lithoclasts) and the cement as a rock cementing the breccias might have the same as tourmalite.We have to admit that typical metasomatic texture and structure,especially linked with tourmalinization,is very rare in this rock.The rock prominently differs from any known unaltered volcanic subvolcanic rocks in chemical and mineralogical composition,and texturally and structurally from any known altered rocks.According to occurrence and relationship with its surrounding rocks,the rock is distinct from tourmalinite formed in sea floor exhalation and evaporate environment.The rock of this kind is not described in the literature.Subject to the term volcanic rock defined by IUGS subcommission on the Systemtics of Igneous Rock,it is clear that the rock is tourmalitic volcanic rock predicted by authors and is named Xizangite in the light of its locality.