Loose limonitic material of millimetre to several centimetre size has been found
at several locations on the peak plateaus of Reiting and Eisenerzer Reichenstein.
These weathered pebbles of rusty dark brown to black colour consist of a mixture
of goethite and hematite. Goethite forms pseudomorphs after another iron pha-
se, likely pyrite. Microbial and colloform microstructures are also documented.
The studied material can be classified as „Bohnerz“; i.e., concretions of limonitic
iron ores formed during karstification and paleoweathering. Bohnerz formation is
thought to be related to the formation of karst plateaus in the central and eastern
Northern Calcareous Alps during the Paleogene to early Neogene prior to sedi-
mentation of the siliciclastic rocks of the Augenstein Formation. These materials
have undergone continuous erosion and became eroded and reworked during uplift
and exhumation of the Northern Calcareous Alps and were resedimented in karst
crevasses and caves.