PHYSICAL EXPERIMENTAS ON STRIKE-SLIP FAULT AND PULL-APART BASIN
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摘要: 本文按照下地壳和岩石圈地幔塑性流动控制上地壳构造变形的思想,采用脆延性双层模型,在考虑模型相似性的条件下,通过延性层流动驱动脆性层进行走滑断裂和拉分盆地模拟实验。实验结果表明,在左行走滑阶段发育两条"S"型左行右阶断裂带;在右行走滑改造阶段,早期左行右阶断裂带被改造为"Z"型右行右阶断裂带。走滑断裂发育过程中共有三种类型的拉张伸展:(1)"S"型破裂逐渐伸展,形成多个菱形盆地;(2)几个相邻的斜列"S"型断裂在剪切作用下端部被错断连通,形成"地堑-地垒"构造;(3)在右行走滑阶段,沿右行右阶断裂拉张形成拉分盆地。先存的上隆拱张断裂限制了走滑断裂的位置和方向。脆性层强度对走滑断裂的形成和发展具有约束作用,脆性层结构对脆延性的层间耦合作用和走滑断裂特征具有显著影响。Abstract: According to the theory that plastic flow of the lower layer (including lower crust and upper mantle lithosphere) controls upper layer (upper crust) deformation in the multi-layer lithosphere, the paper studies the physical experiments of strike-slip fault and pull-apart basin adopted ductile/brittle double-layers model. The experiment results show that strike-slip model developed sinistral right-step fault zone which consisted of a lot of "S"-type faults during sinistral strike-slip stage. The early fault zone was reconstructed and became dextral right-step "Z"-type fault during dextral strike-slip stage.There are three-type extensions in the strike-slip fault zone:(1) a lot of diamond basins formed with stretching of "S"-type fault; (2) the "graben-horst" structure appeared when the ends of adjacent "S"-faults were sheared and connecting; (3) the pull-apart basins formed along right steps of dextral faults during the second strike-slip stage. The stretching faults formed in the stage of uplifting limit the location and the direction of strike-slip faults.Strength of brittle-layer restricts the forming and the development of strike-slip faults, and the texture of brittle-layer influences coupling of brittle-plastic layers and characters of strike-alip faults.
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Key words:
- strike-slip /
- pull-apart basin /
- plastic flow /
- physical models
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