罗云山山前断裂带阶地调查研究及其构造意义

Research on terraces investigation of Luoyunshan fault zone and its tectonic implication

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。对罗云山山前断裂带8条冲沟的阶地测量资料的研究表明: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逐渐增大的趋势,反映该断裂带自晚第四纪以来构造抬升作用逐渐加强,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比较一致。

Abstract:

The Luoyunshan fault zone is located west of Linfen basin，controlling the western border of the basin． The measurement of the terraces in eight gullies along the Luoyunshan fault zone shows that these gullies has five terraces: T1 ～ T5 ． The heights of these terraces are about 3m，8 ～ 10m，about 20m，about 30m and 40 ～ 50m respectively． The dating data of the terraces and the faulted landforms investigation shows that the Luoyunshan fault zone has had many activities since Late Quaternary． Since the Middle-Late Pleistocene an uplift rate of the terraces is 0. 41mm/a，and 0. 75mm/a since Holocene． An increasing trend of the uplift rate of the terraces along the Luoyunshan fault zone from the Middle-Late Pleistocene to Holocene，reflects the tectonic uplift tendency of the fault zone has gradually increased since the Late Quaternary． This is in good agreement with the sedimentation rate of Linfen basin which also has an increasing trend from the Late Pleistocene to Holocene．