Early Miocene pollen and spores from western Jylland, Denmark - environmental and climatic implications

A palynological analysis of a Lower Miocene cored section from Sonder Vium in western Jylland, Denmark, provides new data regarding the vegetation and climate during the earliest Neogene. Most samples yielded well-preserved palynomorphs. Terrestrial pollen and spores dominate, with lesser proportions of dinoflagellates. A fluvial input into the marine setting is corroborated by the presence of freshwater algae, indicating, an inner-neritic setting. A level containing comparatively abundant dinoflagellate cysts probably represents a transgressional event. The late Aquitanian age of the sequence as suggested by previous studies is supported by the composition of the palynoflora, e.g., by the presence of Ephedripites, Platycarya, and the relatively frequent occurrence of Engelhardtia. The pollen record is dominated by Taxodiaceae-Cupressaceae suggesting that swamp forests dominated the onshore region, which is consistent with previous results from central and northern Europe. Besides Taxodium, the swamp forest also contained angiosperm taxa such as Myricaceae, Nyssa, Betula, and Alnus. Elevated or better drained hinterland areas hosted a diverse mesophytic forest, with a ground cover of reeds, sedges and pteridophytes. Abundant pollen taxa derived from mesophytic forests indicates the presence of evergreen conifers, such as Pinus, Sequoia and Sciadopitys, and deciduous angiosperms, including Fagus and Quercus. A decrease in relative abundances of thermophilous elements such as Arecaceae (palms), Ilex, Mastixiaceae and Engelhardtia, in the middle part of the studied succession indicates a possible correlation to the late Aquitanian climatic deterioration. The composition of the palynological assemblages including widely distributed Taxodium swamps, suggests a warm, frost-free temperate climate during the Aquitanian in Denmark