A decompressional P–T path, Reinbolt Hills, East Antarctica

Granulites exposed in the Reinbolt Hills, East Antarctica, are part of the extensive Late Proterozoic granulite complex of East Antarctica, which includes the Rauer Group to the east and the northern Prince Charles Mountains to the west. The deformation history includes three pervasive deformation phases. No chemical or mineralogical distinction between these phases has been detected and this is interpreted to be the result of complete re-equilibration at the end of the third deformation phase. Two late deformation phases post-date the metamorphism and record a medium-temperature cooling path. A short segment of the P–T path of these rocks was inferred from mineral reactions that occurred during these late deformation phases. The path passes from 800°C, 7 kbar to 690°C, 5 kbar, indicating strong decompression, which is typical of a thrust-dominated crustal thickening followed by rapid erosion or extensional collapse.     

Shear Velocity Structure of Jordan From Explosion Seismic Data

Summary. Combined analysis of P - and S -wave data from seismic refraction lines in Jordan has led to the derivation of a Poisson's ratio model for the crust. This model shows that the upper crust, including the sediments, has an average Poisson's ratio of around 0.25, except beneath NW Jordan where the sediments have a high ratio of around 0.32. However, the lower crust below about 20 km depth has high Poisson's ratios ranging from 0.29 to 0.32. These high Poisson's ratios may be interpreted mineralogically in terms of high feldspar and low quartz content in the rocks (e.g. gneiss, amphibolite) of the lower crust or fluid phases in the form of separated penny-shaped inclusions.     

华北1992～1995年GPS复测资料的初步分析

根据华北地区１９９２～１９９５年两期ＧＰＳ复测资料,研究了该地区现今的地壳形变状态。采用坐标平移方法建立近似平面坐标,并在其上进行位移场和应变场的分析。研究结果认为,本区现今地壳形变以区内断块间的相对运动为主,是新构造运动的继承,其中以太行山山前断裂两侧形变场差异性最为明显,是本区的主要活动断块边界带。据此认为未来强震发生在本带的可能性较大。     

西安地区区域地壳稳定性评价

本文依据“七五”期间对西安地区进行区域地壳稳定性与地质灾害评价和研究工作所取得的地质、物探、测量、模拟实验等方面的成果资料,考虑到内、外动力地质作用及介质条件,运用模糊数学方法进行了稳定性评价与区划,将西安地区地壳稳定性划分为较稳定、次较稳定、次较不稳定、较不稳定、不稳定五级。在此基础上,对西安地区主要城市的建设与发展规划提出了指导性的建议。