Gotthard nappe

The Gotthard nappe (German: Gotthard-Decke, in older literature called the Gotthard Massif) is, in the geology of the Alps a nappe in the Helvetic zone of Switzerland. It consists of crystalline rocks that were, before the formation of the Alps, part of the upper crust of the southern margin of the European continent (the northern margin of the Alpine Tethys Ocean).

The Gotthard nappe is found south of its larger neighbour, the Aarmassif. The two crystalline zones are separated by a thin zone of metamorphosed and strongly deformed sedimentary cover rocks of the Tethys sea. In the south, the Simano and Adula nappes lie on top of the Gotthard nappe.

The Gotthard nappe crops out in an elongated strip through the Central Alps. This outcrop begins west of the mountain ridge between the Binntal and the Goms (the valley of the Rhone) east of Brig. It stays south of the Goms and south of the Furka Pass, Andermatt, north of Airolo in the Valle Leventina, south of the Oberalp Pass, Disentis and ends south of the eastern part of the Surselva (the valley of the Vorderrhein).

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