对黑云母暗化轨迹的新解释──以浙江前寒武纪石英闪长岩的黑云母为例

A NEW INTERPRETATION FOR OPACITIZATION LOCUS OF BIOTITE:AN EXAMPLE FOR BIOTITE OF QUARTZ DIORTE FROM PRECAMBRIAN IN ZHEJIANG

在浙江诸暨璜山、桐树林等地的前寒武纪石英闪长岩中，平行于黑云母（010）面的六方放射状裂理，是快速冲击变形事件中形成的显微构造特征，称为黑云母击象（Percussionfigures）。沿黑云母裂理分布的微粒氧化铁暗化轨迹，及其矿物化学式中SiⅥ离子数的降低、A1Ⅵ、TiⅥ、MgⅥ等离子数的升高，晶格参数b（kx）的延展，是事件过程瞬间高温、高压环境的成因标志。黑云母上述特征和多方位扭折带的出现、斜长石显微晶洞的发育，均为该事件引发的有限非稳态场中变形矿物的组合态。本文以此作为探讨，反演石英闪长岩与华夏古地体俯冲过程中，地壳深部古地震（即快速冲击变形事件）成因机制的显微矿物学依据。

Hexagonal radinted parting of biotite parallel (010) face, which was found in quartz diorite from precambrian at Hungshan, Tong shulin in Zhuji of Zhejiang provnce, has microtectonic structure named as percussion figures, which was resulted from fast shocking event. The opacitization locus of small ferric oxide along biotite had ionic number variation in mineral formula (decreasing in siⅥ and increasing in AlⅥ, TiⅥ, and MgⅥ ) with unit cell parameter b (kx) lengthen. These were the origin consequence due to the moment environment of high temperature and high pressure during the event procedure. The above-mertioned characteristics of biotite and the apperance of diversified tograsp as well as the plagioclase microlitic development were the combined prototype of deformed mineral in limited unstable playground which were induced by that event.This can be used as the basis of micro mineralogy in investigating the reasons of deep paleo-earthquake in earth's crust (fast shocking deformed event) during the diving procedure between quartz diorite and cathaysia.