DOI: 10.1016/j.tecto.2020.228593
论文题名: Late Pleistocene slip rate of the Chaman fault based on 10Be exposure dating of offset geomorphic surfaces near Kabul, Afghanistan
作者: Shnizai Z. ; Matsushi Y. ; Tsutsumi H.
刊名: Tectonophysics
ISSN: 00401951
出版年: 2020
卷: 795 语种: 英语
中文关键词: 10Be TCN surface exposure dating
; Afghanistan
; Chaman fault
; Detailed mapping
; Slip rate calculation
英文关键词: Landforms
; Eurasian plates
; Fault-slip rates
; Late Pleistocene
; Parallel component
; Relative motion
; Satellite images
; Terrestrial cosmogenic nuclides
; Topographic data
; Fault slips
; beryllium isotope
; dating method
; deformation
; fault zone
; mapping method
; Pleistocene
; slip rate
; Afghanistan
; Kabul [Afghanistan]
; Kabul [Kabul (PRV)]
英文摘要: We report the first late Pleistocene left-lateral slip rate of the northern Chaman fault in Afghanistan based on 10Be dating of offset alluvial fan surfaces. Field mapping complemented with the analysis of CORONA and ALOS PRISM satellite images and shaded relief and topographic data allows us to identify piercing points across the fault zone at two displaced alluvial fans (Ghat Bandakul and Azadkhail) at Wardak Province south of Kabul. We constrain the ages of offset alluvial fans based on 10Be terrestrial cosmogenic nuclides (TCN) dating of well-embedded quartzite sandstone boulders and cobbles. The Ghat Bandakul alluvial fans are offset at 165 ± 15 m and 235 ± 24 m, for which 10Be TCN model ages average 46.9 ± 3.5 kyr and 66.6 ± 4.9 kyr, respectively, yielding a slip rate of 3.5 ± 0.4 mm/yr. At the Azadkhail site, we identified two offset terraces. Based on 500 ± 50 m offset of a geomorphic surface with 111.2 ± 10.5 kyr age, we obtain a slip rate of 4.5 ± 0.6 mm/yr. Combining the 800 ± 70 m left-lateral offset matching with an average age of 176.8 ± 17.1 kyr for the fan yields the same geomorphic slip rate of 4.5 ± 0.6 mm/yr. These slip rates are considerably lower than geologically, geomorphologically, and geodetically defined slip rates previously obtained along the southern Chaman fault. These results show a clear trend of decreasing fault slip rate with increasing distance to the northeast. The observations suggest that the southern portion of the fault accommodates most of the fault-parallel component of relative motion between the Indian and Eurasian plates. The lower slip rate of the Chaman fault in Afghanistan may be explained by the transfer of the left-lateral shear onto the Gardez and Mokur faults that splay northward from the Chaman fault. © 2020 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/170713
Appears in Collections: 气候变化与战略
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作者单位: Division of Science of Environment and Mathematical Modeling, Graduate School of Science and Engineering, Doshisha University, Japan; Disaster Prevention Research Institute, Kyoto University, Japan; Department of Environmental Systems Science, Faculty of Science and Engineering, Doshisha University, Japan
Recommended Citation:
Shnizai Z.,Matsushi Y.,Tsutsumi H.. Late Pleistocene slip rate of the Chaman fault based on 10Be exposure dating of offset geomorphic surfaces near Kabul, Afghanistan[J]. Tectonophysics,2020-01-01,795