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91.
Kazuhiro Tsukada 《Gondwana Research》2003,6(4):687-698
The Hida marginal belt (HMB), which consists of various kinds of fault-bound blocks, is located between the continental massif of the Hida belt and the Mesozoic accretionary complex of the Mino belt in Central Japan. Detailed field investigation reveals that the HMB had grown through the two different movements, i.e., Jurassic dextral and Cretaceous sinistral movements. The Jurassic dextral ductile shear zones run in the southern marginal part of the Hida belt and the northern part of the HMB, whereas the Cretaceous sinistral cataclastic shear zones occur in the southern part of the HMB and the northern marginal part of the Mino belt. Geologic map and field evidence seem to suggest that the Jurassic dextral movement form the fault-bound blocks of the HMB to form the basic structure of the Hida marginal belt, i.e., formation of the ‘proto-HMB.’ Following the dextral movement, the sinistral one restructured the ‘proto-HMB’ to complete the present feature of the Hida marginal belt. The Cretaceous sinistral movement might result in the sinistral collision between the proto-HMB and the Mino belt. 相似文献
92.
Contrasting metamorphic evolution of metasedimentary rocks from the Çine and Selimiye nappes in the Anatolide belt, western Turkey 总被引:1,自引:0,他引:1
J. L. Régnier U. Ring C. W. Passchier K. Gessner T. Güngör 《Journal of Metamorphic Geology》2003,21(7):699-721
Abstract P–T conditions, mineral isograds, the relation of the latter to foliation planes and kinematic indicators are used to elucidate the tectonic nature and evolution of a shear zone in an orogen exhumed from mid‐crustal depths in western Turkey. Furthermore, we discuss whether simple monometamorphic fabrics of rock units from different nappes result from one single orogeny or are related to different orogenies. Metasedimentary rocks from the Çine and Selimiye nappes at the southern rim of the Anatolide belt of western Turkey record different metamorphic evolutions. The Eocene Selimiye shear zone separates both nappes. Metasedimentary rocks from the Çine nappe underneath the Selimiye shear zone record maximum P–T conditions of about 7 kbar and >550 °C. Metasedimentary rocks from the overlying Selimiye nappe have maximum P–T conditions of 4 kbar and c. 525 °C near the base of the nappe. Kinematic indicators in both nappes are related to movement on the Selimiye shear zone and consistently show a top‐S shear sense. Metamorphic grade in the Selimiye nappe decreases structurally upwards as indicated by mineral isograds defining the garnet‐chlorite zone at the base, the chloritoid‐biotite zone and the biotite‐chlorite zone at the top of the nappe. The mineral isograds in the Selimiye nappe run parallel to the regional SR foliation, parallel the Selimiye shear zone and indicate that the Selimiye shear zone formed during this prograde greenschist to lower amphibolite facies metamorphic event but remained active after the peak of metamorphism. 40Ar/39Ar mica ages and the tectonometamorphic relationship with the Eocene Cyclades–Menderes thrust, which occurs above the Selimiye nappe in the study area, suggests an Eocene age of metamorphism in the Selimiye nappe. Metasedimentary rocks of the Çine nappe 20–30 km north of the Selimiye shear zone record maximum P–T conditions of 8–11 kbar and 600–650 °C. An age of about 550 Ma is indicated for amphibolite facies metamorphism and associated top‐N shear in the orthogneiss of the Çine nappe. Our study shows that simple monophase tectonometamorphic fabrics do not always indicate a simple orogenic development of a nappe stack. Preservation in some areas and complete overprinting of those fabrics in other areas apparently occur very heterogeneously. 相似文献
93.
94.
95.
岩质边坡稳定性分析的探讨 总被引:2,自引:0,他引:2
通过最大剪应力等值线来确定边坡的滑动面,并与其结构面抗剪强度相比较,给出了确定边坡的稳定系数的方法。 相似文献
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97.
大地测量数据接口技术与接口标准 总被引:5,自引:0,他引:5
建立了由接口文件、接口文件处理器和共享信息模型组成的大地测量数据接口体系结构,划分了大地测量数据服务的3类不同接口类型。在建立了面向对象的接口数据模型的基础上,讨论了面向传统用户的控制点数字化成果格式、面向生产过程的大地控制网统一数据结构和面向GIS的大地测量数据交换格式。 相似文献
98.
淮安市典型土动力特性的试验研究 总被引:3,自引:2,他引:3
通过对淮安市典型的全新世沉积粉土和粘性土进行室内自振柱试验及粉土的动三轴液化试验,把粉土和粘性土的自振柱试验结果与Seed和Idriss建议的砂土及饱和粘土的剪切模量比G/Gmax-γ曲线和阻尼比λ-γ曲线的变化范围进行对比,结果表明:粉土的剪模量比要比饱和粘土的大,而比砂土的剪模量比要小,其阻尼比接近于砂土的阻尼比;粘性土的剪模量比要比一般饱和粘土的大,而与砂土的剪模量比相近,其阻尼比要比砂土的略低;粉土的抗液化强度与液化振次之间的关系可以用指数函数来表示,其振动孔隙水压力的发展规律可以用反正弦三角函数拟合;粘粒含量是影响淮安市全新世沉积粉土抗液化强度的主要影响因素。 相似文献
99.
100.
Sarbari Ghosh Utpal Kumar De Atmospheric Science Research Department of Physics Jadavpur University Calcutta India Received April revised July 《大气科学进展》1997,(1)
AComparativeStudyoftheAtmosphericLayersbelowFirstLiftingCondensationLevelforInstantaneousPre-MonsoonThunderstormOcurenceatAga... 相似文献