WEST GONDWANAN ASPECTS OF THE MIDDLE AND UPPER DEVONIAN MIOSPORE ZONATION IN NORTH-AFRICA AND BRAZIL

The stratigraphical distribution of 11 miospore species found so far only in North Africa and Brazil are compared to the range of taxa which characterize the west European based zonation in order to establish accurate determinations. The zonate-camerate miospores that are more or less restricted to the Middle Devonian are the most frequent. Other taxa, often camerate with some tabulate ornamentation, first occur near the Givetian-Frasnian boundary. Three of them are restricted to Brazil. These species are more abundant in the early Givetian. During the late Givetian they are probably more numerous in North Africa than in Brazil. Their relative frequencies strongly decrease during the Frasnian. A greater climatic contrast between the two regions during the late Eifelian (?) and the late Givetian and Frasnian than during the early Givetian is inferred.