甘肃省白银厂黄铁矿型铜矿床火山岩—石英角斑岩熔化实验的初步研究

A PRELIMINARY STUDY OF MELTING EXPERIMENT ON THE VOLCANIC ROCKS-KARATOPHYRES OF THE PYRITE CU-BEARING DEPOSIT OF BEIYINSHANG IN GANSU PROVINCE CHINA

甘肃省白银厂黄铁矿型铜矿床是我国著名的铜矿床之一。它赋存于中寒武世分异较好的富含钠质的海相细碧—石英角斑岩系中。矿床的围岩主要为酸性—中酸性火山岩;含矿岩石为石英角斑岩—石英角斑凝灰熔岩,其浸染状矿石也就是品位达到工业要求的石英角斑岩—石英角斑凝灰熔岩;在矿床附近广布含集块角砾石英角斑岩和酸性次火山岩—石英钠长斑岩,这不仅说明矿床的形成与火山岩活动密切相关,而且是离火山喷发中心较近的部位成矿。因此,研究矿区火山岩的熔化温度和熔化时的各种特征,对于认识岩石、矿床成因将提供一些有益的资料。本文就研究工作中所取得的资料和认识整理成文,供同志们参考,不当之处请批评指正。

Some data of melting temperatures have been ohtained, including the intial melting temperature of the matrix 1000°-1050℃, the completed melting temperature1 050°-1100℃ and the intial melting temperature of the porphyritic crystals 1l60°-1120℃, the completed melting temperature 1150°-1200℃, by the melting experiment at 1 atm for a series of volcanic rocks-karatophyres of Zheyaoshan and Huoyanshan deposits in Beiyinshang. When the homogeneous glasses are formed from the fusion of matrix, a large number of gas bubbles are observed.According to the data mentioned above, it is suggested that the volcanic rocks-karatophyres of this area should belong to the produces of magma which is rich in volatile flux. All of the rocks formed from rapidly cooling magma under the condition close to the crater, are regarded as lava with a diagenetic temperature at 1000°-1150℃.