Geologically speaking, the Montafon is very diverse. In his geological contribution to the history of Montafon, Christian Woldersdorfer names five geological-tectonic building blocks. They are the Northern Lime Alps, the Grauwachen zone, the Silvretta Kristallin the Pennine units and the quaternary deposits.

The northern Lime Alps comprise about one fifth of the area in Montafon and are exposed in the northern and western areas of the Montafon.  They are the most diversified part with many different types of rocks. To name a few of them, there are sand stones, clay, lime and dolomite stones. The stone wall in Vandans as well as the Zimba, which you will recognize as a striking rock formation if you look to the west, belongs to this unit.

The grauwacken zone is a 200 meter wide strip made up of carboniferous to Pennine rocks, that is situated between the Silvretta Kristallin and the Northern Lime Alps.  This zone makes up about one percent of the area in the Montafon and runs from Rellstal over the Bartholomaeberg to the Kristberg, where you are now.  One of the characteristics of the Grauwacken zone are the variations of dark clay stones, sand stones, arkose, lime and marl stone.

The Silvretta Kristallin and the Phyllitgneis zone cover about 75% of the Montafon.  They are mostly to the south of where you are standing in the communities of Schruns, Silbertal, St. Gallenkirch and Gaschurn.  What makes it distinctive are the gneiss, mica slate, phyllite, granite gneiss as well as amphibolites which originate from various stones and are creased in the millimetre area as well as the kilometre area. Tectonically, the Silvretta Kristallin belongs to the Eastern Alps sediments.  It is a lot older as the Eastern Alpine rocks of the Northern Lime Alps.  The Montafon has the oldest cohesive rocks in Vorarlberg. 

The Pennine rocks can be found on the Swiss border and in the geological window of Gargellen.  Even though these rocks only make up about six percent of the area of the Montafon, together with the Sulzfluh Lime, they shape the landscape in the valley the most.  You can see them in the southwest in the form of the mountains, Sulzfluh, the Drei Türme or Three towers, and the Drusenfluh.

The quaternary deposits will be talked about in the next information point.