Assessing the temporal patterns of mid-Cretaceous floral change in Portugal - a palynological and chemostratigraphic approach

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The rise of angiosperms to ecological dominance during the mid-Cretaceous coincided with a dramatic drop in the diversity of many gymnosperm and pteridophyte lineages. In contrast to the wealth of information available on the biology and systematic relationships of early angiosperms, the temporal patterns of their evolution and radiation and its impact on coexisting plant communities are still poorly constrained. Here, I propose to study the fossil pollen associations of marine near-shore and continental deposits from the Portuguese Lusitanian Basin, an area well known for its exceptional angiosperm mesofossil floras. Age assignment of the pollen-bearing marine strata will be based on biostratigraphy coupled with high-resolution C- and Sr-isotope stratigraphy. The palynofloras of both study areas will be analysed qualitatively and quantitatively using up-to-date microscopy techniques (DIC-TL, CLSM, SEM) with special focus on angiosperm pollen. Correlation with the marine-derived pollen record will provide an improved age constraint for the famous mesofossil floras of the northern Lusitanian Basin. The combined chemostratigraphic and palynological approach of this proposal will provide new insights into terrestrial ecosystem dynamics during a critical phase of pronounced diversification of angiosperms during the Albian-Early Cenomanian.