First palynostratigraphical evidence for a Late Eocene to Early Miocene age of the volcano-sedimentary series of Dschang, western part of Cameroon and its implications for the interpretation of palaeoenvironment

摘要

AbstractThe volcano-sedimentary infill of the Dschang basin in the Western part of Cameroon is poorly known. The present study provides the first biostratigraphical data of the volcano-sedimentary sequence and allows constraining the age and the position of this basin within the regional context of Central Africa. The studied sequence is composed of three depositional units. The first unit is a fining-upwards sequence of coarse-grained sandstone that gets finer towards the top, passing to thick layers of fossiliferous claystone. The second unit is strongly affected by volcanic activity and consists of a volcano-sedimentary sequence. The third unit is marked by basaltic volcanism and covers the series. Diverse and well-preserved palynomorphs were recovered and are used to provide valuable information for age determination of the Dschang volcano-sedimentary sequence, namely to be of late Eocene- Early Miocene age. The recovered spores, pollen, green algae and fungal remains from the bottom of the sequence includeBombaciditesspp.,Clavainaperturitescf.clavatus,Crototricolpitessp.,Perfotricolpites digitatus,Proteaciditesspp.,Psilastephanocolporites minor,Psilastephanocolporitesspp.,Retitrescolpitesspp.,Retitricolporites irregularis,Retitricolporitesspp.,Retitriporitessp.,Spirosyncolpites bruni(probably synonymous toSpirosyncolpites spiralis),Striatopollis