Gosau Group at Muttekopf
The Gosau Group at Muttekopf is one of the key research areas regarding synorogenic sediments and soft sediment deformation. It is the most spectacular and highest outcrop of the Gosau Group in the eastern Alps and sits on top of one of the large thrust sheets of the Northern Calcareous Alps (see location map in the drop-down menu below). Deep water sediment gravity flow deposits were deposited onto a growing syncline-anticline system during the Late Cretaceous. Some highlights of the geology of the Muttekopf area are shown here. Most of the images were published in Ortner (2001) and Ortner (2007), where you find further details on the geology of the area.
Use the links below to see panoramic views of the area.
Location map of the Muttekopf Gosau outcrop in the western part of the Northern Calcarepous Alps of Tyrol.
Panoramic view of the Kogelseespitze-Parzinn ridge (photograph taken from Leiterspitze). Folded Triassic bedrock (Hauptdolomit, grey) is truncated by deep marine clastics of the Upper Gosau Subgroup.
View of the Plattigspitze. A fold pair in Triassic bedrock is truncated by deep marine clastics of the Upper Gosau Subgroup, which displays progressively less folding to the top.
Panoramic view of the ridge from Reichspitze to Schlenkerspitze from the west. The steep southern limb of the Muttekopf syncline, center right, is affected by several angular unconformities, partly related to northward tilting. The angular unconformity in the foreground below Plattigspitze shows south-directed tilting of the northern flat limb of the Muttekopf syncline. Check out the following drop-down link for a closer view of the Schlenkerkar unconformity.
The Schlenkerkar unconformity is the most prominent angular unconformity in the Gosau Group of Muttekopf. Synsedimentary fold growth is not only shown by angular unconformities, but also by depocenters of coearse-grained beds in the core of the syncline.
Panoramic view of the ridge from Muttekopf to Rotkopf from the WSW. Megasequence 3 cuts into Megasequence 2 at the Rotkopf unconformity. In the center below Rotkopf rotational overlap within Megasequence2 in the growth triangle shows synsedimentary growth of the fold system.
Panoramic view of the ridge from Muttekopf to Rotkopf, Pleiskopf and Alpjoch from the east. Click the image for a larger version. The southern limb of the Muttekopf syncline is deformed by several minor thrusts und thrust-related folds, like the Alpjoch syncline or the folds in the northern face of Pleiskopf. These thrusts are related to a major thrust that brings the Larsenn Klippe on top of Gosau deposits. In a megabreccia bed (center right), several huge boulders of Upper Triassic limestones were redeposited.
Panoramic view of the Larsenn ridge to Rotkopf from the southeast. Megasequence 3 cuts into Megasequence 2 at the Rotkopf unconformity. Right of the center a tear dextral tear fault cuts the sedimentary sequence.
North of Ödkarleskopf, the Gosau Group deposits are overthrust by the Larsenn-Klippe, which belongs to the tectonically highest unit of the western Northern Calcareous Alps, the Krabachjoch thrust sheet.
Several fault-related folds crop out in the north face of Pleiskopf. The coarse-grained beds were not fully lithified during deformation, and flow of material toward the fold hinges caused thickening of fold hinges.
View from the Alpjoch to the south face of Muttekopf, where large blocks of limestones are resedimented in the megabreccia layer above the base of the 2nd Megasequence.