Palynology of the Geulhemmerberg Cretaceous/Tertiary boundary section (Limburg, SE Netherlands)

Abstract

The newly found, relatively complete section across the Cretaceous/Tertiary (K/T) boundary in the Geulhemmerberg caves contains rich and well-preserved palynological assemblages. Stratigraphically diagnostic dinoflagellate cysts indicate that the lower part of the Geulhemmerberg succession represents the latest Maastrichtian and that an early Danian age may be assigned to sediments overlying the Berg en Terblijt Horizon, notably on the basis of the appearance of Senoniasphaera inornata. On the basis of quantitative palynological analysis, the sediments are interpreted to represent relatively marginal marine, inner neritic conditions, with nearby landmasses providing important terrestrial input. Almost all terrestrial palynological elements are most probably derived from Bryophyta (mosses). Their sudden proliferation at the K/T boundary may be associated with increased transport from the coastal plain, and/or it may reflect a major change in the terrestrial ecosystem at K/T time. Changes in the palynomorph distribution are probably mainly caused by differing hydrodynamical conditions, possibly combined with slightly varying waterdepths and/or the introduction of restricted marine conditions.