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Eckart Håkansson, Institute of Geography and Geology (Denmark)
Claus Heinberg, Roskilde University (Denmark)
Erik Thomsen, Geological Institute, University of Aarhus (Denmark)
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When the Chixulub bolide crashed into the Yucatan carbonate platform at the time of the Cretaceous-Tertiary boundary, it created a near instant global havoc. However, depending on distance from the impact, ?directness' in marine connections, etc. local effects should be expected to vary profoundly.
The Danish Basin was situated thousands of kilometers away from Chixulub, in a comparatively sheltered position with respect to tsunami waves and other direct physical influence from the impact. With its uninterupted marine record and extraordinarily rich benthic faunas through most of the boundary succession, it therefore constitutes a very crucial element in the understanding of the ecological conditions after this global catastrophe.
In the Danish sections (Stevns Klint, Nye Kløv, a.o.) the faunal recovery has been clarified in great detail, revealing a succession of rapidly changing faunas through the basal Danian, reaching its diversity climax level near the top of zone NP1.. The very first benthic faunas are of low diversity and density, and throughout the recovery interval very little but Mesozoic remnants participate. However, recovery patterns in the major benthic invertebrate groups differ dramatically in terms of both biominerals and timing. Through the initial parts of the recovery interval the faunas are essentially devoid of taxa with low-Mg calcite skeletons. Considering the widespread precipitation of low-Mg calcite in the Danish Basin through this very interval, a highly unusual and adverse sea-water chemistry must have existed in the period after the impact.
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