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

Plate 5
Scheibelberg –
Type location of the Scheibelberg Formation, situated north of Steinplatte / Kammerköhr Alm.
(A): Outcrop of Hornsteinknollenkalk and Kendlbach limestones along the tourist trail from
Schwarzlofer Alm passing the western slope of Scheibelberg mountain.
(B): Large boulder of corroded Hornsteinknollenkalk penetrated by several siliceous bulbs.
Rettenbachalm / Jaglingbach –
Liassic sedimentation from the southern part of the Triassic carbonate platform (East of Bad
Ischl, Höllengebirgs nappe).
(C): View over the river bed of Jaglingbach that is formed by folded Adnet limestone. At the
upper right corner: Grey siliceous limestones of the Allgäu Formation.
(D): Anticline of knobby Adnet limestones with ferromanganese crusts at the Jaglingbach river
bed.
(E): Breccia of Adnet limestone clasts with high amounts of isolated spicules (grey color).
Contact seams between clasts are characterized by pressure solution and microstylolites.
Scanned thin section.
(F): Close-up of one of the clasts in (E), exhibiting spicules of collapsed sponge skeletons.
(G): Adnet breccia. Cluster of spicules embedded in microbialite (lighter red). The mixture of
isolated monaxons, hexactins (white arrows) from Lyssacinosid species and dichotriaen
spicules of demosponges (black arrow) illustrate the problem to characterize allochthonous
and autochthonous components of the sediment.