| Popis: |
The recognition of five standard conodont biozones and five radiolarian zones in the same set of samples from cherts within the Frasnian–Famennian (F–F) boundary interval at Bancheng, southeastern Guangxi, China allowed precise placement of the F–F boundary, and demonstrated the multi-episodic pattern of the F–F mass extinction. Frasnian pelagic radiolarian and conodont faunas had an acme in the lower Palmatolepis linguiformis Zone. In the upper Pa. linguiformis Zone, until the level of the upper Kellwasser extinction (Kw.), members of the radiolarian family Ceratoikiscidae and of the conodont Frasnian populations disappeared. Above the Kw, in the lower Palmatolepis triangularis Zone, new populations of the conodont Pa. triangularis gradually appeared and the survivor radiolarian genus Trilonche gradually re-appeared, both blooming in the lower part of the middle Pa. triangularis Zone. The Nehden extinction (Nd) in the uppermost middle Pa. triangularis Zone interrupted the recovery of the conodont and radiolarian faunas, but above this level the conodont species became more numerous, and the post-extinction radiolarian faunas (including Entactiniidae) recovered gradually. |
Full Text from ScienceDirect