Gian Luigi Trombetta
Facies analysis, geometry and architecture of a Carnian carbonate platform: the Settsass/Richthofen reef system (Dolomites, Southern Alps, northern Italy)

Geo.Alp 8, 2011, p. 56–75

The Settsass/Richthofen Reef carbonate platform system, together with the other central-western Dolomites postvolcanic carbonate complexes, forms the palaeogeographic scenario of the Lower Carnian. These Lower Carnian platforms were dwelled by coral patch-reefs and sponge mounds separated by small lagoons characterized by muddy sedimentation. The Settsass/Richthofen Reef is a small platform system (3-4 km2 in plain view and about 150 m thick) and is characterized by two superimposed carbonate complexes (DC 1 and DC 2) showing different geometric features:
a) the lower complex, known as the Richthofen Reef (DC 1), shows a plane-convex geometry where the core is constituted by coral patch-reefs and sponge bodies, while the lateral portion is represented by the slope sediments interfingering with the basinal deposits (San Cassiano Formation);
b) the upper complex, the proper Settsass relief (DC 2), shows a tabular geometry and/or some thickening basinward. This upper complex covers a variety of depositional settings, from inner platform deposits (back-reef) at the southwestern side, to slope deposits at the southeastern side. Its slope deposits are formed by clinostratified breccias with slope angles ranging from 20° - 25° in the proximal area, to 10° - 15° more distally. The Settsass platform complex shows a basinward progradation (NE direction) which can be traced in outcrops for almost 2 km.

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