桂西土湖锰矿区泥盆系中的陡崖式假不整合构造

桂西下雷、土湖锰矿区于上泥盆统榴江组—五指山组—融县组—下石炭统巴平组与中泥盆统北流组之间，发育了一种特殊的、呈陡崖状的高角度“上超”状的地层接触关系——陡崖式假不整合。通过对下雷、土湖锰矿区该类型不整合的发育位置、产状、界面及图面效应等特征，尤其是横向沉积接触典型特征的研究，得出了其是在海底陡坡、悬崖等特定古地形条件下，形成的一种新老地层间的横向沉积接触关系，而非存在间断的上下地层关系的认识。土湖锰矿区的这种高角度上超接触关系，形成始于中泥盆世吉维特期晚期至晚泥盆世之初，是中泥盆世晚期广西海域大裂解事件的产物，是造盆运动形成的一种横向沉积构造，与同生断裂有着密切的关系。这一发现对认识地层接触关系、不整合的多样性，对右江盆地的古地理格局、盆地发展演化史及赋存锰矿的深入研究具有重要意义。

Characteristics of Escarpmentive Pseudounconformity in Devonian Tuhu Manganese Deposit, Western Guangxi

A special,cliffy,high-obliquity and onlap stratigraphic contact relationship,escarpmentive pseudounconformity,is developed generally between middle Devonian(Beiliu formation,late Devonian liujiang formation and Rongxian formation) and lower Carboniferous(Baping formation).Based on the characteristics of escarpmentive pseudounconformity in Tuhu manganese ore deposit,it is found that the contact relationship results from a specific palaeogeography with an escarpment during the late Givetian to the late Devoni...