Spore characterisation and its taxonomic significance in ferns fromLagos State, Nigeria

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Palynology from ground zero of the Chicxulub impact, southern Gulf of Mexico

Palynological analysis of Site M0077A in the Chicxulub impact crater has yielded a record of the immediate Cretaceous/Paleogene (K/Pg) recovery from ground zero of the end-Cretaceous mass extinction, followed by a record of the Paleocene–Eocene Thermal Maximum (PETM) and later Ypresian (Eocene), including the Early Eocene Climatic Optimum (EECO). Eight specimens of the dinoflagellate cyst Trithyrodinium evittii have been observed near the base of the K/Pg transitional unit; these likely representa post-impact dinoflagellate disaster recovery assemblage deposited within several days following the impact, although the possibility that some or all of the T. evittii specimens are reworked Maastrichtian cysts cannot be fully excluded. Despite high-resolution sampling of the lowermost Paleocene successions, the oldest identifiable terrestrial palynomorphs observed in the Site M0077A core, two specimens of Deltoidospora fern spores, occur at least c. 200,000 years after the impact. Other than these occurrences, the Paleocene section is nearly barren in terms of palynomorphs, likely a result of poor preservation of organic material combined with a long recovery time for vegetation in the vicinity of the crater. Pollen and fungal spore concentrations spike in an anoxic dark shale deposited during the PETM around 56 Ma, with a diverse pollen assemblage indicating the presence of a coastal shrubby tropical forest in the geographic vicinity, likely in the Yucatan Peninsula to the south. In the marine realm, this interval is characterized by thermophilic assemblages of dinoflagellate cysts. Stratigraphically constrained cluster analysis identified four statistically robust sample clusters in the lower Eocene successions, with Malvacipollis spp. and Milfordia spp. abundances driving the highest average dissimilarity between clusters. A second notable spike in palynological concentrations above the PETM section may represent another early Eocene hyperthermal event. Pollen and plant spore concentrations generally increased during the EECO, associated with increases in terrestrial input during basin infilling.Also funded by the Research Foundation Flanders (FWO grant 12Z6618N)</p

Late Cretaceous spore-pollen zonation of the Central African Rift System (CARS), Kaikang Trough, Muglad Basin, South Sudan: angiosperm spread and links to the Elaterates Province

This paper presents a first detailed study on and new zonation scheme for the Kaikang Trough, Muglad Basin of South Sudan. The Kaikang Trough lies within the central sediment locus of the Muglad Basin, a non-marine African cratonic basin within the Central African Rift System (CARS) Two wells, KW-1 and K-4, were examined leading to the recognition of five palynological assemblage zones: K-I (early–middle Cenomanian), K-II (late Cenomanian), K-III (Turonian?–Santonian), K-IV (Campanian–Maastrichtian) and K-V (Maastrichtian). The elaterate group are peculiarly absent in otherwise rich Cenomanian palynological assemblages of the Muglad Basin. Why this is so, and the implications for the global middle Cretaceous Elaterate Province, needs some explanation. The CARS provided a range of diverse freshwater alluvial and lake-shore substrates. Its cross-continent sweep may have played a role in the evolution and dispersal of floras including early angiosperms as the rift basin of the proto-South Atlantic became a permanently flooded fjord