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

Plate 2
Mühlstein-South –
Hornsteinknollenkalk and Adnet facies from the southern flank of the Mühlstein mountain.
(A): Large outcrop inside the forest encompassing Hornsteinknollenkalk (Scheibelberg Fm.)
and Adnet limestones/breccias passing at the top into Oxfordian radiolarites. Samples of 2
B/C derives from its lowest part (ammonite icon).
(B): Polished slabs of a Hornsteinknollenkalk layer highlighting a bulbous siliceous horizon.
The siliceous matter (grey color) encloses sediment, clasts and sponge fragments. Irregular
outlines and bottle-neck segments implies that accumulation of siliceous fluid was
influenced by different densities of the host rock.
(C): Large Arietites sp. obtained from the subsurface of the same layer as shown in (B).
(D): Adnet facies. Knobby limestone with a high ratio of biodetritus and dislocated spicules of
collapsed and partly fragmented Demosponges.
(E): Adnet facies showing the skeletal remain of a hexactinosid sponge species.