Geomorphic Evidence for Recent Right-lateral Shear of Karakorum Fault Along Indus-Yalu Suture Zone of Tibet(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2016年第04期
- Page:
- 483-493
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Geomorphic Evidence for Recent Right-lateral Shear of Karakorum Fault Along Indus-Yalu Suture Zone of Tibet
- Author(s):
- WANG Shi-feng; JIANG Wan; WANG Chao
- 1. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China; 2. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
- Keywords:
- Karakorum fault; Gangdise granite belt; shutter ridge; stream channel offset; geomorphic evidence; optically stimulated luminescence; slip rate
- PACS:
- P542
- DOI:
- -
- Abstract:
- The existence active slip along Karakorum fault (KKF) in the east of Pulan graben is debated. One interpretation is that the KKF extends eastward along the Indus-Yalu suture zone and accommodates large magnitudes right-lateral shear; another interpretation is that the displacement along the KKF is absorbed by structures bounding Pulan graben and Gurla Madhata detachment system. The kinematic and geometric characteristics of the KKF along a 400 km long segment of the Indus-Yalu suture zone between Mt. Kailas and Lopugangri ranges were reported. The results show that the evidence of recent deformation is characterized by offset streams, fault scarps, sag ponds, and shutter ridges; streams show a consistent right-lateral deflection; offsets vary from as little as tens of meters to as much as (11±1)km, and basement rocks also show the same sense of offset with (7±1)km; a region of transpression at Mayoumu Pass is interpreted to have absorbed 4 km of right-lateral displacement along the KKF, and about 7 km offset is transferred to Darong-Qiongguo Basin and possibly as far east as Lopugangri Range; a Holocene slip rate of (4.0±0.3)mm per year for this segment of the KKF is calculated based on (84±2)m right-lateral shutter ridge offset and optically stimulated luminescence ages of samples from sands and clays in the ridge ranging from (9.4±0.8)ka to (21.7±1.6)ka; the KKF is interpreted to have propagated to south-central Tibet since 3 Ma if the (11±1)km offset occurs at Holocene slip rate keeping steady since Pliocene; right-lateral shear along the KKF in the western Himalaya is comparable to the distributed left-lateral shear documented from Dinggye to Chigu Co along the Indus-Yalu suture zone in the eastern Himalaya. It is suggested that this spatial distribution of strike-slip deformation is best explained by active oroclinal bending of Himalayan thrust wedge.
Last Update: 2016-07-19