A Large Transpression Zone at the South Margin of the East Kunlun Mountains and Oblique Subduction

• 来源期刊: 大陆动力学（英文版）
• 学科: 地球科学
• 关键词: East Kunlun Mountains transpression zone oblique convergence and subduction western Datan and eastern Datan A'nyemaqen Maji snowberg
• 年，卷（期）: 2001,（1）
• 页码范围: 25-34
• 页数: 10页
• 分类号: P5
• 语种: 英文

摘要

The convergent boundary between the East Kunlun terrane and the Baryan Hara-Songpan Garze terrane of northern Tibet plateau is a large transpressional zone on the south margin of the East Kunlun Mountains. The deformation structures are different between the eastern segment (A'nyemaqen segment) and western segment (western Datan and eastern Datan segment). The structures of the A'nyemaqen segment are characterized by superimposed thrust slices with southwest orogenic polarity formed during the stage of Indosinian collision-orogeny and brittle sinistrai strikeslip faults formed during Cenozoic. The western Datan and eastern Datan segment consists dominantly of an E-W-trending ductile sinistrai strike slip transpression zone companied by a NW-SE trending fold and fault zone on its both sides, which formed 220 Ma ago. The ductile deformation continued till 220 Ma BP and then the deformation was manifested by the reactivation of the brittle sinistral strike-slip deformation structures. Therefore, the large convergence zone on the south margin of the East Kunlun Mountains is a very special tectonic zone which changed gradually from the "Constrictive compression" in the eastern segment to the "transpression" in the western segment. Its formation was related to northeastward oblique subduction of the Baryan Hara-Songpan Garze terrane beneath the East Kulun terrane since Indosinian.