晚白垩世西峡盆地和夏馆盆地古地震事件的发现及意义

Discovery and significance of the palaeoseismic events in the Late Cretaceous Xixia and Xiaguan Basin

以大量的野外工作为基础,辅以地球化学研究,确定了西峡盆地和夏馆盆地普遍存在着古地震事件的物质记录。同沉积期古地震事件主要表现为同沉积小断裂、同沉积角砾岩层等,且同沉积地震事件对于河流侵蚀作用的产生具有重要的影响;成岩期古地震事件主要表现为沿断裂上盘砾岩的"涂抹"和成岩期形成的方解石擦磨晶体,以及由断裂(裂隙)所围限的不同于周侧岩性的块体。古地震事件的研究不仅可以为恐龙蛋的埋藏作用提供信息,也可以为研究古地理和古构造背景提供信息。

The palaeoseismic events in the Late Cretaceous Xixia and Xiaguan Basin may fall into two categories： synsedimentary and diagenetic.The synsedimentary palaeoseismic events led to the formation of synsedimentary faults and breccias horizons,and exercised an important effect on the erosion of rivers.The diagenetic palaeoseismic events are manifested in the ＂smear＂ phenomena of conglomerates along the hanging wall of faults,rubbing of calcite crystals,and fault-bounded blocks which are different from the surrounding rocks.The study in this paper may provide useful approaches not only to the burial of dinosaur eggs but also to palaeogeography and palaeotectonic settings.