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.
Wang Yongsheng,Zhu Guang,Song Chuanzhong et al. A STUDY ON RELATIONSHIP BETWEEN TECTONIC DIFFERENCE STRESS AND ADDITIONAL TECTONO-INDUCED HYDROSTATIC PRESSURE[J]. Chinese Journal of Geology, 2007, (1): 70-83.