Figure 1
The Alps.
(a) Geologic map illustrating locations of megafans together with areas in the Alps where the material sources have been located between the Late Oligocene and the Early Miocene. L = Lepontine dome situated in the back of the Alps that was considered to represent the area where the crystal detritus was derived from; B = Bergell pluton; CVM = Cressim-Vanzone-Mischabel backfold; IL = Insubric Line. The map has been drawn based on Schlunegger and Kissling18 using Illustrator 15.1.0 licenced to Uni Bern. (b) Restored section of the Alps for the Late Oligocene18 together with the locations where the megafans were deposited. Slab breakoff beneath the back of the Alps caused a rebound of the European lithosphere, which was accomplished by backthrusting along the Insubric Line (IL) together with the build of the Alpine topography. The Cressim-Vanzone-Mischabel (CVM) backfold was the major drainage divide between the Late Oligocene and the Early Miocene14,15. The section runs from Zurich to Milan (Fig. 1a). The section has been drawn based on Schlunegger and Kissling18 using Illustrator 15.1.0 licenced to Uni Bern.
