[关键词]
[摘要]
罗云山山前断裂位于山西临汾盆地西侧,控制着盆地的西界。通过对该断裂1∶ 5万地质填图、对河流冲沟阶地及山前断错地貌的调查,介绍了罗云山山前断裂中段土门-贾朱村晚第四纪断错地貌特征。罗云山山前发育D1、D2、D3 等3 级洪积扇,罗云山山前断裂上升盘冲沟发育T1 ~ T5 等5 级阶地。D1 洪积扇与T1、T2 阶地形成于全新世早中期;D2 洪积扇与T3 阶地形成于晚更新世中晚期;D3 洪积扇与T4、T5 阶地形成于中更新世中晚期。罗云山山前断裂中段不同部位断错地貌特征差异较大,D1 洪积扇的断错在席坊沟一带断距约2. 9m;在金殿镇峪口村南西山前断错约3m。D2 洪积扇的断错在土门镇南西堡子村约2. 5m;在杨家庄村西山前断错约4m;在景村西山前断错约6m;在襄陵镇浪泉沟南西侧山前断错约7. 7m。罗云山山前断裂中段山前断错地貌明显,其最新活动时代为全新世。其中,土门段最新活动时代为全新世早期,龙祠段最新活动时代为全新世中晚期。罗云山山前断裂中段晚更新世中晚期以来活动速率为0. 18~ 0. 54mm / a,由北向南活动呈增强趋势;全新世早中期以来活动速率为0. 4 ~ 0. 9mm / a,断裂活动主要集中于席坊沟-峪口一带。罗云山山前断裂中段从晚更新世中晚期到全新世活动速率有增大的趋势,这与该断裂上升盘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以及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。
[Key word]
[Abstract]
The Luoyunshan piedmont fault is located in west of Linfen basin,controlling the western border of the basin. Based on the fault 1 ∶ 50000 geological mapping,river and gully terraces and piedmont faulted landforms survey,this paper mainly introduces late Quaternary faulted landforms characteristics on the Tumen-Jiazhu village segment of Luoyunshan piedmont fault. The Luoyunshan piedmont alluvial-pluvial fans are divided into three stages,named as alluvial-pluvial fans D1,D2,and D3 . The gullies on the upthrown plate of Luoyunshan piedmont fault has five terraces: T1 ~ T5 . Alluvial-pluvial fans D1 and terraces T1 and T2 formed in the early and middle Holocene. Alluvial-pluvial fans D2 and terraces T3 formed in the middle-late stage of late Pleistocene. Alluvial-pluvial fans D3 and terraces T4 and T5 formed in the middle-late stage of middle Pleistocene. Faulted landforms characteristics on different parts of the middle segment of the Luoyunshan piedmont fault are different. The dislocation of alluvial-pluvial fans D1 is about 2. 9m and 3m respectively in the Xifanggou area and the piedmont of southwest of Yukou village, Jindian town. The dislocation of alluvial-pluvial fans D2 is about 2. 5m,4m,6m and 7. 7m respectively in the southwest of Puzi village,Tumen town,piedmont of west of Yangjiazhuang village,west of Jingcun village and piedmont of southwest of Langquangou,Xiangling town. The faulted landforms on the Tumen-Jiazhu village segment of Luoyunshan piedmont fault are obvious. The latest activity times of the fault is Holocene. The latest activity times of Tumen segment and Longci segment of the fault are early Holocene and middle-late Holocene respectively. Since the Middle-Late Pleistocene an activity rate of the middle segment of Luoyunshan piedmont fault is 0. 18 ~ 0. 54mm / a,and activity showed an increasing trend from north to south. Since Early- Middle Holocene it is 0. 4 ~ 0. 9mm / a,and fault activities mainly concentrated on the segment from Xifanggou to Yukou village. There was an increasing trend of the activity rate of the middle segment of Luoyunshan piedmont fault from the Middle-Late Pleistocene to Holocene. It is in good agreement with an increasing trend of the uplift rate of the terraces on the upthrown plate of the fault from the Middle-Late Pleistocene to Holocene and the sedimentation rate of Linfen basin from the Late Pleistocene to Holocene.
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[基金项目]
中国地震局地壳应力研究所基本科研业务专项( ZDJ2013-17 )、地震行业科研专项( 200908001 )共同资助