摘要
晚泥盆世弗拉斯—法门期(Frasnian—Famennian)之间存在一次全球性生物绝灭事件(简称F—F事件)。这次事件在西秦岭地区有所表现。西秦岭中带西成地区吉维特到弗拉斯期为碳酸盐台地和生物礁沉积。法门期以暗灰色和灰绿色板岩、粉砂质板岩沉积为主。弗拉斯期末(相当于gigas最上亚带),该区大量的层孔虫、珊瑚、腕足及兰绿藻等生物绝灭。沉积相、矿物及地球化学特征都表明该事件是山于海水急剧加深引起的。事件发生的时间为gigas上亚带和最上亚带之间。
There existed an event of global mass extinction between the Frasnian and Famennian of the Late Devonian. This event affected the West Qingling region.
nn the Givetian-Frasnian stages, there occurred carbonate platform and organic reef deposits in the Xicheng area in the middle sector of the western Qinling Mountains; while in the Famennian stage, the deposits in the area were mainlyrepresented by dark-grey and greyish-green slate and silty slate. Large numbers of stromatoporoids, corals, brachiopoids, tentaculitids, trilobites, ammonoids and bluegreen algae became extinct at the end of the Frasnian stage (equivalent to the uppermost gigas subzone). The characteristics of sedimentary facies, mineralogy and geochemistry suggest that this event was caused by the rapid deepening of the seawater. The event occurred between the upper gigas subzone and the uppermost gigas subzone.
出处
《地质论评》
CAS
CSCD
北大核心
1990年第1期50-57,共8页
Geological Review
