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摘要: |
罗云山山前断裂带位于山西临汾盆地西侧,控制着盆地的西界。根据罗云山山前断裂带8条冲沟的阶地测量资料研究表明,该断裂带冲沟发育T1~T5五级阶地。T1阶地拔沟3m左右,T2阶地拔沟8~10m,T3阶地拔沟20m左右,T4阶地拔沟30m左右,T5阶地拔沟40~50m。阶地测年数据及断错地貌调查表明,罗云山山前断裂带在晚第四纪以来有过多次活动。晚更新世中晚期以来阶地的抬升速率为0.41mm/a,全新世以来抬升速率为0.75mm/a。罗云山山前断裂带冲沟阶地从晚更新世中晚期到全新世抬升速率有增大的趋势,反映该断裂带自晚第四纪以来构造抬升作用有逐渐加强的趋势,这与临汾盆地从晚更新世晚期到全新世沉降速率也有增大的趋势具有较好的一致性。 |
关键词: 罗云山山前断裂带 阶地 晚第四纪 抬升速率 构造意义 |
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Investigation of Terraces along the Luoyunshan Piedmont Fault Zone and Its Tectonic Implications |
Sun Changbin, Xie Xinsheng, Xu Jianhong
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Laboratory of Crustal Dynamics,Institute of Crustal Dynamics,CEA, Beijing 100085,China
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Abstract: |
Located at the west of the Linfen basin,the Luoyunshan piedmont fault zone controls the western boundary of the basin. According to the measurements of the terraces in eight gullies along the Luoyunshan fault zone,five levels of terraces,namely T1 ~ T5 have developed in these gullies. The heights of terraces T1,T2,T3,T4 and T5 are about 3m,8 ~ 10m,about 20m,about 30m and 40 ~ 50m,respectively. The dating data of the terraces and investigation of the faulted landforms show that the Luoyunshan fault zone has experienced much activity since the Late Quaternary. The uplift rate of the terraces was 0. 41mm / a since the Middle-Late Pleistocene,and 0. 75mm / a since the Holocene. The increasing trend of uplift rate of the terraces along the Luoyunshan fault zone from the Middle-Late Pleistocene to Holocene indicates the tendency of gradual tectonic uplift of the fault zone since the late Quaternary. This is in good agreement with the increasing trend of subsidence rate of the Linfen basin from the Late Pleistocene to Holocene. |
Key words: Luoyunshan piedmont fault zone Terrace Late Quaternary Uplift rate Tectonic implication |