喜马拉雅山南部的构造复杂性

根据对恒河盆地西部的多振型宽频带面波频散资料的分析推断,该区的地壳结构不具有大陆地盾的特征,相反,却非常象某些海洋高地。这一异常的海洋型地壳与恒河盆地东部地盾地壳的分界线可能在阿拉瓦利山脉（Aravalli Ridge）。该处地壳的地质特征具有异常高的电导率,其走向垂直于喜马拉雅山脉。目前广为接受的假定认为是构造均匀的印度大陆岩石圈向喜马拉雅山下俯冲。本文的研究结果对此观点提出了置疑:在北部印度大陆内的地壳运动可能存在着差异。我们追溯印度-欧亚大陆的碰撞历史,这个因素恐怕是不容忽视的。

THE STRUCTURAL COMPLEXITY SOUTH OF THE HIMALAYAN ARC

Interpretation of multi-mode, broadband surface wave dispersion data in the western Ganga Basin has led to the conclusion that the underlying crustal structure is not characteristic of continental shield, and instead is strongly feminiscent of certain oceanic plateaus. The boundary separating this anomalous crust of oceanic affinity and the shield crust of the eastern Ganga Basin is likely to be at the Aravalli Ridge, a subcrustal geological feature of abnormally high electrical conductivity, which strikes perpendicular to the Himalayas. The results of the analysis presented in this paper casts doubt on the validity of the widely accepted hypothesis of a structurally uniform Indian continental lithosphere underthrusting beneath the Himalayas. It raises the possibility that differential crustal movements within the northern Indian continent may be an important consideration in the reconstruction of the Indian-Eurasia continental col-lisional history.