Greywacke zone

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The greywacke zone is a band of Paleozoic sedimentary rocks in the Austrian Alps. The zone is part of the Austroalpine nappes.

Mesozoic limestones crop out north of the greywacke zone, forming the Northern Calcareous Alps. South of the zone basement rocks of the Austroalpine and Penninic nappes form the Central Eastern Alps.

The lithologies of the greywacke zone are:

• Paleozoic turbidites (among them greywackes) and limestones of Ordovician to Devonian age.
• felsic and mafic volcanic rocks of Ordovician age

The rocks have formed at a passive margin of the Paleo-Tethys Ocean, when the Austroalpine terrane was part of the microcontinent Avalonia. Together with the other Austroalpine units, they were thrusted over the European plate during the Alpine orogeny.

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Last updated on Saturday January 19, 2008 at 01:28:21 PST (GMT -0800)
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