14. Reconstruction - Stage 3
The rising sea level, caused by continuous subsidence of the foreland,
reaches the northern-most part of the depositional basin. Terrigenous input
only occurs along the coast, high zones are completely flooded. The rate of
carbonate sedimentation can keep up with rising sea level in the northern
area. Fragmentation of coralline algae is low. Crustose frameworks are
restricted to the swells. The peyssonneliacean limestones reflect the
occurrence of muddy areas deeper than in stages 1 and 2. In contrast to the
algal limestones of the northern area, sedimentation rate of the southern area
is too low to keep up with the rising sea level. Some glauconite is formed.
The Bryozoa Facies suggests an environment below the photic zone. Coralline
detritus originate from the northern area and can be interpreted as grain
flows reworking bryozoans.
The dominance of bryozoans can be alternatively interpreted by
eutrophication. The eutrophication of the environment caused a high water
turbidity and did not allow the occurrence of light-dependent organisms. In
this case, the overlying algal-dominated facies may represent a progradation
of (par)autochthonous algal sediments.
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