Formed in Mesozoic-Cenozoic time, the Kuche depression on the south side of Tianshan and the Urumqi depression on the north side of Tianshan demonstrate striking similarities in geometry, kinematics and dynamics. However, the seismic activities, especially middle and large earthquakes show evident differences between the two depressions. This paper analyses the primary factors that cause the differences. They include: 1. the difference in deformation extent between the two depressions; 2. the difference in fine structure of gophysics between the two depressions; 3. the difference in the environment of geodynamics between the two depressions.

This paper deals with the mineralogical and petrological features of eclogites from Mts. Hongtushan and Qinglongshan of the Donghai region, Jiangsu province. According to the experimental results of related rocks the genetic condition of eclogites can be estimated as T = 890° - 1275℃ and P = 17.25-24.75kb, and at the depth of 50-70km. From the petrochemical characters, the parent rock of eclogites can be considered as tholeiitic basalt. It can be assumed that the evolutionary process of eclogites in studied region started with metamorphism of tholeiitic basalt into basic granulite, and then, the basic granulite further turned into eclogite due to the dynamic process of progressive metamorphism. This process can be expressed by means of 0.61 hypersthene + plagio-clase (An = 61) = Omphacite (Jd = 39) + 0.61 kyanite + quartz. Finally, the eclogites a℃ompanied by the faulting intruded into the supracrustal migmatitic gneisses. In this process the temperature was decreasing from 1080℃±190℃ to 750℃±80℃, and the pressure from 21.0kb±3.75kb to 4.0kb±2.5kb. So that, the sequent retrogressive metamorphism of eclogites was caused by the dynamic effect of faulting. The conditional formula of this dynamic metamorphism can be approximately expressed as P(kb) = 0.0506T(C)-33.65.