川西龙门山前缘地质地球物理解释

通过地面地质观察和地球物理资料解释,作者认为龙门山区及其前缘有着东西分带、南北分块的构造特点:即由三大断裂带控制的四个构造带,以及前缘依据其构造风格所确立的三个块体;建立了犁式断层、阶状断层、波状断层、穹背式断层和平移断层等5种断裂模型,以及与断裂作用有关的褶皱构造和与断层组合有关的褶皱构造两类断层-褶皱组合模型;提出了龙门山地区印支晚期-喜山期由西向东的背驮式迁移;并在上震旦统底、志留系、下三叠统和上三叠统4个构造层次上滑脱。处在现今龙门山前渊深部的古生界、中生界内有着良好的与逆冲断层密切相关的构造圈闭。 

GEOLOGICAL AND GEOPHYSICAL INTERPRETATIONS FOR THE FORELAND OF THE LONGMENSHAN,WESTERN SICHUAN

On the basis of the data derived from surface geologic observation and geophysics, the author considers that the Longmenshan Area and its foreland are characterized by the alignment of east-west zones and south-north blocks. Consequently, five fault models are established respectively for listric faults,terrace-faults, undulate faults, dome-faults and strike-slip faults,as well as two folding structural models related to faultings and fault assemblages. Thereafter, it is proposed that the area underwent piggyback shiftings from east to west during the time of the Indosinian-Xishanian and four detachments have been brought about along the four tectonic levels at the bottom of the Upper Sinian, Silurian, Lower and Upper Triassic systems respectively. It is believed that the excellent structural traps closely related to thrusts would develop in the Palaeozoic and Mesozoic systems, at the deeper depth of the Longmenshan Foreland.