六盘山东麓断裂南段断裂沟槽韵律沉积特征对最新活动时代的限定 |
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关键词:the south segment of the eastern Liupanshan piedmont fault the rhythmic deposits of the fault grooves analysis of the profile 14C dating three times geological events active fault |
基金项目:中国科学院战略性先导科技专项子课题(编号: XDB03020201);国家自然科学基金重点项目(编号: 41030317) |
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The Recent Active Time of the South Segment of the Eastern Liupanshan Piedmont Fault: Constraints from the Characteristics of Rhythmic Deposits in the Fault Grooves |
The Liupanshan region is located in the transitional tectonic zone between the Ordos block of the western North China block and the Qilianshan orogenic belt of the northeastern Qinghai-Tibetan block. Generally the eastern Liupanshan piedmont fault may be divided into northern, middle and southern segments. The groove sedimentation on the active fault is displayed as the structure of the rhythm sequences that consist of the many alternate coarse beds and fine beds. Each circle of rhythmic deposits was caused by a movement of the fault. A profile of the rhythmic deposits of the fault grooves in the south segment of the eastern Liupanshan piedmont fault was discovered. Three circles of the rhythmic deposits were discerned on the profile. The characteristics of the rhythm sedimentation on the profile are considered to have been caused by a few geological events. The results of sampling and dating from the deposits of the fault grooves suggest that the south segment of the eastern Liupanshan piedmont fault expereicned remarkable movements after about 500 a BP, after about 6 ka BP and before about 15 ka BP respectively. It can be confirmed that the recent activity of the south segment of the eastern Liupanshan piedmont fault is evident and this segment of fault has expereinced several movements since the Late Pleistocene. Hence, the south segment of the eastern Liupanshan piedmont fault is active. |
SHI Zhi-gang,LI Ting-dong,YUAN Dao-yang,LIU Xing-wang,DING Xiao-zhong,GENG Shu-fang.2014.The Recent Active Time of the South Segment of the Eastern Liupanshan Piedmont Fault: Constraints from the Characteristics of Rhythmic Deposits in the Fault Grooves[J].Acta Geoscientica Sinica,35(1):31-37. |
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