Fig. 6

Field photographs. All coordinates in Swiss coordinate system CH1903/LV03. Abbreviations of lithologies according to Fig. 5. Some picture locations and view directions are indicated in Figs. 1 and 2. a Verrucano-Breccia on top of Chalchhorn (727′372/192′188) seen from top of Ringgenchopf (727′538/191′877). The bottom Verrucano boundary is very irregular; hence it cannot correspond to the main Glarus Thrust but belongs to the Crena-Martin Slice. b View from northern slope of Rotstock (727′662/190′727) towards NNE. The visible formations from bottom-left to top-right are Taveyannaz Fm. (brown in the grass) and Ultrahelvetic Wildflysch (dark gray-black) of the Cavorgia Slice, Quinten Fm. (light gray limestone) of the Prau-Lurign Slice, and Dogger (greenish-brown), Schilt Fm. (light brownish gray), and Quinten Fm. (light gray limestone) of the Tschep Nappe. Well visible is the near-vertical position of all formations. Häxenseeli at bottom-right corner. Position and view direction of a is indicated. c View from top of Rotstock (727′558/190′175) towards east into the cirque of Alp da Bovs. Well visible are the light orange-brown outcrops of Triassic dolomite (Röti Fm.) of the Crena-Martin Slice. Dark greenish-gray outcrops to the lower-right belong to Verrucano-Breccia of the Crena-Martin Slice. The Quinten Fm. in the foreground belongs to the Piz d’Artgas Nappe; the Quinten Fm. in the back belongs to the Tschep Nappe. Position of d is indicated. d Calc-mylonite on the main Glarus Thrust between Verrucano-Breccia of the Crena-Martin Slice (below) and Verrucano-Phyllite of the Helvetic Nappes (above) in the area of Alp da Bovs (728′627/189′983). The foliation exhibits a distinct angle to the thrust plane. In the Helvetic Nappes, this orientation corresponds to the regional orientation; in the Crena-Martin Slice, the foliation rotates into this orientation within a short distance below the Glarus Thrust (see e). Orange field book for scale. e Main Glarus Thrust above the Prau-Lurign Slice on western slope of Rotstock (727′273/189′924). The slope is too steep to take a picture perpendicular to the transport direction; hence there is a significant distortion. Nevertheless, the bending of foliation into the Glarus Thrust can clearly be identified. Picture width approx. 5 m. f Detail 2 m left of e of the calc-mylonite along the Glarus Thrust. The mylonite exhibits small-scale folds with a clear vergence towards north, which are however cut by later brittle overprint. Pencil for scale. g View from Fil dil Fluaz (725′640/189′860) towards east. Two generations of folds within the Taveyannaz Fm. and Ultrahelvetic Wildflysch of the Cavorgia Slice can be identified, the earlier one with a shallow (blue) and the later one with a steeper (green) SSE-dipping axial plane. The basal thrust of the Prau-Lurign Slice (i.e., Quinten Fm.) cuts the earlier fold but is involved in the later one. Below the Taveyannaz Fm., so-called Globigerina marl of the Cavorgia Slice is outcropping; however, this lithology is not present on our geological map. This view roughly corresponds to the cross-section of Oberholzer (1933) (Fig. 10). Position of e and f is indicated. Picture courtesy of Y. Deubelbeiss