一种可能的非稳态流变的超糜棱岩

辽宁省四道沟金矿床的黑色超糜棱岩为丹东韧性剪切带早期强烈活动的产物,它相当于前人划分的所谓“含石墨绢云石英片岩”、“石墨片岩”类。这类岩石发育了特征的黑色滑面构造。研究表明,黑色滑面的物质构成并非石墨,而是一些以绢云母成分为基础的黑色极细粒似玻璃物质,它们的形成可能反映了岩石快速滑动变形的结果。因此,这类超糜棱岩的流变学性质不是典型的稳态流变,面属于非稳态流变。黑色超糜棱岩本身即可能为一种非稳态流变的超糜棱岩。

A KIND OF ULTRAMYLONITE WITH POSSIBLE PROPERTY OF NONSTEADY STATE FLOW

Black ultramylonite developed in Sidaogou gold deposit, Liaoning province, is the result of early strong deformation of the Dandong ductile shear zone. It consists mainly of quartz and sericite and exhibits ultramylonitic characteristics. According to the observation of microstructure and analysis of chemical compcsition for three types of tectonite, we determine that the ultramylonite was derived from arkcse, quartz sandstone. The black ultramylonite represents the most highly strained rock in the Dandong ductile shear zone. In the past, however, the black material of ultramylonite was considered to be graphite, and correspondingly the uhramylonite was regarded as graphite-bearing sericite quartz schist. In fact, chemical analysis indicates that the black material are neither graphite nor carbon. They appear to be glass materials. Therefore, the formation of ultramylonite represents deformation of rapid strain rate. If so, the ultramylonite is a kind of ultramylonite with property of nonsteady state flow.