构造运动和气候变化对天山北麓奎屯河阶地发育的影响作用
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摘要
奎屯河出天山后,强烈下切形成深达300m的河谷,在河谷两侧发育多级河流阶地。在遥感解译和野外测量的基础上,获得了河流阶地平面分布图和阶地位相图。根据奎屯河阶地的平面特征与剖面特征,将河流阶地由新到老分为T1,T2,T3,T4和T5等5组。前人用~(10)Be测年数据认为T4阶地堆积于深海氧同位素(MIS)第2阶段,奎屯河强烈下切开始于MIS 2后期,形成于距今1.3万年;本文~(14)C年龄数据说明T2阶地形成于3100±40kaB.P.,其发育与亚北方期的偏凉气候有关;根据河流平均下切速率估算T3阶地形成于10.6kaB.P.,其发育可能与新仙女木冷期有关。因此,认为阶地发育明显受控于气候变化。在独山子背斜区,T4阶地相对于T3阶地的抬升量为12m,隆起速率为5mm/a,T3阶地以来的拱曲抬升量为13m,隆起速率为1.2mm/a,反映末次冰期以后,独山子背斜隆起速率早期较大,晚期明显变小。独山子断层将T2阶地垂直错断3.7m,断层垂直活动速率为1.09～1.14mm/a,与同时段背斜隆起的速率相近,说明该时段隆起量主要由独山子断层垂直活动所引起,背斜拱曲变形有限。奎屯河T5阶地的3个小阶地反映独山子背斜向南扩展,造成抬升下切与下降淤积区的界线随时间向南侧迁移。奎屯河西岸T4阶地面上的羽状阶地陡坎反映在T4阶地发育期间,发生5次上游下切与下游堆积区的界线向下游迁移事件,这可能受独山子背斜间歇性隆起的影响,更可能是西南侧托斯台背斜抬升影响的结果。独山子背斜南翼在T3阶地形成以后发生4次曲流向北迁移的事件,在时间上与独山子断层全新世古地震时间相关,说明受独山子背斜隆起中心在奎屯河东岸的影响,奎屯河发生向西转弯,独山子断层多次活动,伴随背斜的隆起,引发河流4次弯曲和曲流向背斜轴部的4次迁移事件。
The Kuitun River down-cut about 300m and left several river terraces in the northern piedmont of Tianshan Mountains.Based on remote sensing image interpretation and field measurement,the terraces were mapped and a longitudinal profile of river terraces was obtained.According to planar and longitudinal characteristics,the river terraces were divided into five groups.Be dating indicated the T4 was deposited in MIS 2,and down-cut around 13 kaB.P.The age of the T3,estimated to be 10.6kaB.P.with average down-cutting rate,is coincident with the Younger Dryas cold event.The T2 terrace,with C age of 3100±40kaB.P.,was probable to be correlated with the cooler climate in Sub-Boreal period. In the area of Dushanzi anticline,the uplift between T4 and T3 was 12m with an uplift rate of 5mm/a,the uplift of T3 related to river profile was 13m with an average rate of 1.2mm/a,indicating that the uplift rates of Dushanzi anticline were greater at earlier stage and became smaller at later stage after the ending of the Last Glacial Stage.The Dushanzi fault has vertically dislocated T2 by 3.7m with a rate of 1.09～1.14mm/a,similar to the rate of anticline uplift,showing the anticline uplift mainly originated from the movements of Dushanzi fault rather than the arching of Dushanzi anticline.The development of three terraces of T5 suggested southward expansion of Dushanzi anticline,making the boundary between aggradation and degradation migrated southward.On the west bank of Kuntun River,5 pinnate terrace risers which developed on the surface of T4 showed five aggradation and degradation boundary migration events,which were possible to be influenced by uplift of Dushanzi anticline in the north,but were more likely to be the effect of tectonic uplift of Tuositai anticline in the southwest.There were four northward migration events of meander channels in the south limb of Dushanzi anticline since T3 formed.They had good correlation with Holocene paleo-earthquakes that happened along Dushanzi Thrust in time,indicating that the coseismic uplift of the Dushanzi anticline,with uplift center on the east bank of the Kuitun River,caused four river deflections and four migration events.
The Kuitun River down-cut about 300m and left several river terraces in the northern piedmont of Tianshan Mountains.Based on remote sensing image interpretation and field measurement,the terraces were mapped and a longitudinal profile of river terraces was obtained.According to planar and longitudinal characteristics,the river terraces were divided into five groups.Be dating indicated the T4 was deposited in MIS 2,and down-cut around 13 kaB.P.The age of the T3,estimated to be 10.6kaB.P.with average down-cutting rate,is coincident with the Younger Dryas cold event.The T2 terrace,with C age of 3100±40kaB.P.,was probable to be correlated with the cooler climate in Sub-Boreal period. In the area of Dushanzi anticline,the uplift between T4 and T3 was 12m with an uplift rate of 5mm/a,the uplift of T3 related to river profile was 13m with an average rate of 1.2mm/a,indicating that the uplift rates of Dushanzi anticline were greater at earlier stage and became smaller at later stage after the ending of the Last Glacial Stage.The Dushanzi fault has vertically dislocated T2 by 3.7m with a rate of 1.09～1.14mm/a,similar to the rate of anticline uplift,showing the anticline uplift mainly originated from the movements of Dushanzi fault rather than the arching of Dushanzi anticline.The development of three terraces of T5 suggested southward expansion of Dushanzi anticline,making the boundary between aggradation and degradation migrated southward.On the west bank of Kuntun River,5 pinnate terrace risers which developed on the surface of T4 showed five aggradation and degradation boundary migration events,which were possible to be influenced by uplift of Dushanzi anticline in the north,but were more likely to be the effect of tectonic uplift of Tuositai anticline in the southwest.There were four northward migration events of meander channels in the south limb of Dushanzi anticline since T3 formed.They had good correlation with Holocene paleo-earthquakes that happened along Dushanzi Thrust in time,indicating that the coseismic uplift of the Dushanzi anticline,with uplift center on the east bank of the Kuitun River,caused four river deflections and four migration events.
引文
1 Burnett A W,SchummS A.Alluvial-river response to neotectonic deformation in Louisana and Mississipi.Science,1983,222:49-50
2 Bull W B.Geomorphic Response to Climate Change.New York; Oxford University Press,1991.192-211
3 Bull W B.Tectonic Geomorphology of Mountains:A New Approach to Paleoseimology.Oxford:Blackwell Publishing,2007,42-68
4 Merritts D J,Vincent K R,Wohl E E.Long river profiles, tectonism,and eustasy:A guide to interpreting fluvial terraces. Journal of Geophysical Research,1994,99(B7):14031-14050
5 Starkel L.Climatically controlled terraces in uplifting mountain areas.Quaternary Science Reviews,2003,22(20):2189-2198
6 Vandenberghe J.Climatic forcing of fluvial system development:An evolution of ideas.Quaternary Science Reviews,2003,22(20): 2053-2060
7杨景春,李有利.地貌学原理.北京:北京大学出版社,2005. 48-54 Yang Jingchun,Li Youli.Geomorphology.Beijing:Peking University Press,2005.48-54
8杨景春,李有利.活动构造地貌学.北京:北京大学出版社, 2011.48-56 Yang Jingchun,Li Youli.Active Tectonic Geomorphology.Beijing: Peking University Press,2011.48-56
9朱海之,陈杰.新疆独山子山前活断层和活褶皱及古地震研究.内陆地震,1990,4(2):97-106 Zhu Haizhi,Chen Jie.The discovery and research of active faults, active folds and paleoearthquakes on Dushanzi piedmont.Inland Earthquake,1990,4(2):97-106
10 Molnar P,Brown E T,Burchfiel B C et al.Quaternary climate change and the formation of river terraces across growing anticlines on the north flank of the Tien Shan,China.Journal of Geology, 1994,102(5):583-602
11邓起东,冯先岳,张培震等.天山活动构造.北京:地震出版社, 2000.127-141,283-288 Deng Qidong,Feng Xianyue,Zhang Peizhen et al.Active Tectonics of the Tian Shan Mountains.Beijing:Seismology Press,2000.127- 141,283-288
12 Avouac J P,Tapponnier P,Bai P et al.Active thrusting and folding along the northern Tien Shan and Late Cenozoic rotation of the Tarim relative to Dzungaria and Kazakhstan.Journal of Geophysical Research,1993,98(B4):6755-6804
13 Burchfiel B C,Brown E T,Deng Q D et al.Crustal shortening on the margins of the Tian Shan,Xinjiang,China.International Geology Reviews,1999,41(8):665-700
14 Lu H H,Burbank D W,Li Y L et al.Late Cenozoic structural and ??stratigraphic evolution of the northern Tian Shan foreland.Basin-Research, 2010,22(3):249 -269
15钱蟒,李有利,司苏沛等新疆独山子的冲沟发育与断层新活动.地理学报,2012,67(5):681-688 Qian Mang,Li Youli,Si Supei et al.Gullies evolution and fault activities in Dushanzi,Xinjiang.Acta Geographica Sinica,2012,67 (5):681 -688
16 Zhao J D,Song Y G,King]W el al.Glacial geomorphology and glacial history of the Muzart River valley,Tianshan Range,China. Quaternary Science Reviews,2010,29(11 - 12):1453 - 1463
17 Lowe J J,Ammann B,Birks H H et al.Climatic changes in areas adjacent to the North Atlantic during the last glacial-interglacial transition(14 - 9ka BP ).Journal of Quaternary Science,1994,9 (2):185 -198
2 Bull W B.Geomorphic Response to Climate Change.New York; Oxford University Press,1991.192-211
3 Bull W B.Tectonic Geomorphology of Mountains:A New Approach to Paleoseimology.Oxford:Blackwell Publishing,2007,42-68
4 Merritts D J,Vincent K R,Wohl E E.Long river profiles, tectonism,and eustasy:A guide to interpreting fluvial terraces. Journal of Geophysical Research,1994,99(B7):14031-14050
5 Starkel L.Climatically controlled terraces in uplifting mountain areas.Quaternary Science Reviews,2003,22(20):2189-2198
6 Vandenberghe J.Climatic forcing of fluvial system development:An evolution of ideas.Quaternary Science Reviews,2003,22(20): 2053-2060
7杨景春,李有利.地貌学原理.北京:北京大学出版社,2005. 48-54 Yang Jingchun,Li Youli.Geomorphology.Beijing:Peking University Press,2005.48-54
8杨景春,李有利.活动构造地貌学.北京:北京大学出版社, 2011.48-56 Yang Jingchun,Li Youli.Active Tectonic Geomorphology.Beijing: Peking University Press,2011.48-56
9朱海之,陈杰.新疆独山子山前活断层和活褶皱及古地震研究.内陆地震,1990,4(2):97-106 Zhu Haizhi,Chen Jie.The discovery and research of active faults, active folds and paleoearthquakes on Dushanzi piedmont.Inland Earthquake,1990,4(2):97-106
10 Molnar P,Brown E T,Burchfiel B C et al.Quaternary climate change and the formation of river terraces across growing anticlines on the north flank of the Tien Shan,China.Journal of Geology, 1994,102(5):583-602
11邓起东,冯先岳,张培震等.天山活动构造.北京:地震出版社, 2000.127-141,283-288 Deng Qidong,Feng Xianyue,Zhang Peizhen et al.Active Tectonics of the Tian Shan Mountains.Beijing:Seismology Press,2000.127- 141,283-288
12 Avouac J P,Tapponnier P,Bai P et al.Active thrusting and folding along the northern Tien Shan and Late Cenozoic rotation of the Tarim relative to Dzungaria and Kazakhstan.Journal of Geophysical Research,1993,98(B4):6755-6804
13 Burchfiel B C,Brown E T,Deng Q D et al.Crustal shortening on the margins of the Tian Shan,Xinjiang,China.International Geology Reviews,1999,41(8):665-700
14 Lu H H,Burbank D W,Li Y L et al.Late Cenozoic structural and ??stratigraphic evolution of the northern Tian Shan foreland.Basin-Research, 2010,22(3):249 -269
15钱蟒,李有利,司苏沛等新疆独山子的冲沟发育与断层新活动.地理学报,2012,67(5):681-688 Qian Mang,Li Youli,Si Supei et al.Gullies evolution and fault activities in Dushanzi,Xinjiang.Acta Geographica Sinica,2012,67 (5):681 -688
16 Zhao J D,Song Y G,King]W el al.Glacial geomorphology and glacial history of the Muzart River valley,Tianshan Range,China. Quaternary Science Reviews,2010,29(11 - 12):1453 - 1463
17 Lowe J J,Ammann B,Birks H H et al.Climatic changes in areas adjacent to the North Atlantic during the last glacial-interglacial transition(14 - 9ka BP ).Journal of Quaternary Science,1994,9 (2):185 -198
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