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1 Introduction
The Berg en Terblijt hardground is a unique
layer, because of the many fossils with a very good preservation
state found in there. On top of this hardground a bioclast grit
layer was deposited. The top of the Berg en Terblijt hardground
is probably the Cretaceous/ Tertiary boundary (K/T) (Vonhof &
Smit, 1996), although some research results do not support that
(Smit & Brinkhuis, 1996).
The purpose of the fieldwork carried out in the
Curfs quarry in Berg en Terblijt was to determine the relation
between the Berg en Terblijt hardground, the bioclast grit
layers on top, the clay layers, and the K/T boundary. There are
several hypotheses about the forming of the Berg en Terblijt
hardground. First, the hardground is a normal hardground like
the other hardgrounds in the Meerssen member. The second
hypothesis is from Zijlstra, 1996, and comprises the deposition
of a stormlayer over the hardground and thus preserving the fossils
present. The third hypothesis is also the deposition of a storm
layer on top of the hardground, but now as a result of the Chicxulub
meteorite impact in the Gulf of Mexico at the end of the Cretaceous
period.
To test the hypotheses, seven sections were sampled,
measured, and correlated in the Curfs quarry from several meters
below the "Berg en Terblijt" hardground until the Vroenhoven
horizon above if possible. To compare the bioclast grit layer
and hardground to a 'normal' sequence, four sections were measured
in the Meerssen member in the ENCI quarry. The grainsize,
roundness, sedimentary structures, and the mesofossil content
of the sequences from both locations were compared.
© 1999
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