Porifera-microbialites of the Lower Liassic (Northern Calcareous ...

Localities (Facies and Sponge Analyses) 45
� “Red limestones, presumably Lias α-ζ” – Outcrops in the forest (samples LW 2, 4, 6-8,
Pl. 6E-F): Different facies types encompassing echinoderm biomicrites, ostracod-echinoderm-
foram biomicrites and sponge biomicrites. The latter show isolated sponge spicules mostly
scattered randomly in the matrix. Only a few spots also show spicule clusters and skeletal
structures of sponge tissue remains.
� “Triassic-Jurassic boundary section” – Outcrop southwest of the runnel (samples LW 9-12,
14): Triassic Dachsteinkalk is represented by peloidal biomicrites with a high ratio of
micropeloidal automicrites and forams (Triasina sp.). Like in the most southern outcrop, they are
overlain here by red limestones of ostracod-foraminifer-spicule biomicrites of Adnet facies type
associated, too, with ferromanganese crusts that cover clasts of mainly echinoderm biomicrites.
The succession continues with biomicrites of different microfacies type showing different small
amounts of sponge remains.
Fig. 24. Supposed profile of the Luegwinkel area formed by Triassic Dachsteinkalk that is heterogeneously
covered by Liassic sediments of different age. Information about ammonite findings from G. Wolf (Vigaun-
Hallein).
Sponge Analyses:
� In most of the red limestones sponges are relatively scarce and represent only a minor part of
the allochemes. Small remains of skeletal structures points to the fact that most of the sponge
bodies collapsed and were fragmented before and/or during dislocation. A higher ratio of
automicrites detected inside badly preserved skeletal structures let assume syndiagenetic,
microbially induced carbonate precipitation in decaying sponge organic matter.