Event Deposits near F-F Boundary in Nandan-Hechi Basin and Their Origin
A suite of event deposits,isochronous and interrelated in origin,are widely found near the Frasnian-Famennian boundary in Nandan-Hechi Basin of Guangxi,South China.From the platform margin to the inter-platform rift trough,the event deposits are divided into debris,grained flow and turbidity deposits.They are mainly composed of rudstone,calcirudite,massive homogenites and turbidites.They occur between linguiformis and triangularis Zone and can be correlated in the stratohorizon to Liujing section of Hengxian,Yangdi of Guilin,Du'an of Debao,Nandong of Wuxuan,Xiangtian of Xiangzhou,Nayi of Chongzuo,Yunpan of Shanglin and to the turbidite in the bottom of the Lower in Hony railroad cut of Belgium,Devils Gate of Nevada,USA,Atrous of Morocco,South Urals and Fore-Kolyma of northeastern Siberia of Russia,and to erosional discontinuities and brecciation in the Frasnian-Famennian boundary in South Polish-Moravian shelf.It is assumed that the event deposits could be caused by a violent tsunami related to bolide impacts into ocean.