构造差应力与构造附加静水压力关系研究  

A STUDY ON RELATIONSHIP BETWEEN TECTONIC DIFFERENCE STRESS AND ADDITIONAL TECTONO-INDUCED HYDROSTATIC PRESSURE

作　　者：王勇生[1] 朱光[1] 宋传中[1] 刘国生[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009

出　　处：《地质科学》2007年第1期70-83,共14页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金资助项目(批准号:40272094)

摘　　要：构造差应力究竟能够产生多大的附加静水压力在地学界一直有很大争议。本文通过大别山东端郯庐韧性剪切带中糜棱岩的构造差应力测量和同构造新生白云母的电子探针分析，对这一科学问题进行了初步探讨。对该断裂带12个糜棱岩样品进行了20次构造差应力测量，获得了114．6—149．6MPa的差应力值；对同构造新生白云母的电子探针分析获得岩石的形成时的围压为291．7—531．3MPa。通过构造差应力与岩石围压的对比分析，笔者认为岩石中的“构造超压”并不完全是构造差应力产生的附加静水压力造成的，还应包括了岩石中流体压力的贡献。在中-上地壳，附加静水压力主要由流体压力构成；而在下地壳和岩石圈深部，岩石的构造超压主要来自于由构造差应力产生的附加静水压力。但由于岩石圈深部构造差应力的急剧减小，产生的构造附加静水压力对围岩的贡献量极小，并不能使超高压岩石的形成深度明显变浅。It is in disputed that how much additional tectono-induced hydrostatic pressure can be produced by tectonic difference stress. The paper explored primarily this problem by measuring difference stress and taking electron microprobe analysis on syngenetic muscovite of mylonites from the Tan-Lu fault zone on the eastern terminal of Dabie Mountains. In this work, twenty difference stresses were measured for twelve mylonites and obtained difference stress from 114.6 MPa to 149.6 MPa. Furthermore, the syngenetic muscovites were took electron microprobe analysis and obtained total pressure being 291.7 - 531.3 MPa. According to contrasted difference stress with the total pressure, the authors thought that the tectonic over-pressure caused incompletely by additional hydrostatic pressure from additional tectono-induced hydrostatic pressure. It might be produced partially by fluid pressure. In middle-upper crust, the additional hydrostatic pressure was mainly fluid pressure, and in lower crust and lithospheric mantle, the additional hydrostatic pressure was mainly from additional tectono-induced hydrostatic pressure caused by difference stress. Therefore, difference stress decreased rapidly with depth increasing in deep of lithosphere, produced few additional hydrostatic pressure, which could not make the formational depth of UHP rocks becoming shallower markedly.

关 键 词：构造差应力 构造附加静水压力 流体压力 糜棱岩 郯庐断裂 

分 类 号：P542[天文地球—构造地质学]