Rheology of the continental lithosphere: Progress and new perspectives
Rheology of the continental lithosphere: Progress and new perspectives
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DOI：
10.1016/j.gr.2011.07.013
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发表时间：
2012
影响因子：
6.1
通讯作者：
Wang-Ping Chen;S. Hung;T. Tseng;M. Brudzinski;Zhaohui Yang;R. Nowack
中科院分区：
文献类型：
--
作者：
Wang-Ping Chen;S. Hung;T. Tseng;M. Brudzinski;Zhaohui Yang;R. Nowack
当西藏表面经历普遍的纯剪切时，横跨地下缝合的稳定地体留在次大陆岩石圈地幔(SCLM)中，证明了其强度。此外，从喜马拉雅形变前缘向北追踪了近水平的、粘结的印度SCLM残留物约600公里，证明了太古宙地盾浮力强的SCLM的寿命。地震深度呈双峰型分布，峰值集中在上/中地壳和莫霍面附近，这是长期存在的强SCLM的证据。喜马拉雅-西藏和东非裂谷系统的最新结果不仅证实了双峰分布，而且坚定地证实了大地震发生在莫霍面以下。有趣的是，非火山震动--新发现的弹性应变释放方式--也发生在莫霍面附近，但远低于上/中地壳的地震孕育区。考虑到最近的野外观测和莫霍面上的粘性对比的实验室实验，SCLM必须足够强大，以便在地质时期积累弹性应变，这是地震的先决条件。此外，在实验室条件下，将摩擦不稳定性的终止、地震的类似物和晶体塑性开始联系起来的最新进展，为地壳(~300-400℃)和地幔(~600-700℃)地震的极限温度提供了物理基础。虽然任何单一的流变模型都不可能解释所有的构造环境(也随时间演变)，但莫霍面上的岩性对比对于塑造大陆岩石圈强度的双峰分布是重要的。
While the surface of Tibet is undergoing pervasive pure shear, stable terranes, straddling subsurface sutures, remain in the sub-continental lithospheric mantle (SCLM), attesting to its strength. Furthermore, sub-horizontal, cohesive remnant of Indian SCLM is traced northward from the Himalayan deformation front for about 600km, exemplifying the longevity of buoyant, strong SCLM of Archean shields. Bimodal distribution of earthquake depths, with peaks concentrating in the upper/middle crust and near the Moho, has been a longstanding evidence for strong SCLM. Recent results from the Himalayas—Tibet and along the East African rift system not only corroborate the bimodal distribution but also firmly established that large earthquakes occur below the Moho. Intriguingly, non-volcanic tremors—newly discovered mode of elastic strain release—also occur near the Moho but well below the seismogenic zone in the upper/middle crust. Considering recent field observations and laboratory experiments of viscosity contrast across the Moho, the SCLM must be strong enough to accumulate elastic strain, a prerequisite for earthquakes, over geological time. Moreover, under laboratory conditions, recent advances that link the termination of frictional instability, an analogue for earthquakes, and the onset of crystal plasticity, provided a physical basis for limiting temperatures of crustal (~300–400°C) and mantle (~600–700°C) earthquakes. While any single rheological model cannot possibly account for all tectonic settings (which also evolve with time), lithological contrast across the Moho is important in shaping the bimodal distribution of strength in the continental lithosphere.