Geology of the Colle di Tenda – monte marguareis area (Ligurian Alps, NW Italy)

Abstract

The 1:25,000 geological map of the Colle di Tenda – Monte Marguareis area covers an area of about 130 km 2 in the Italian Ligurian Alps, between the Vermenagna and Tanaro valleys. It is a detailed geological map of a sector of the Ligurian Alps of renewed scientific interest, and represents the eastern continuation of a recently published geological map of the Entracque-Colle di Tenda area. In addition to the increased detail and scale, the more relevant new contents of this map are represented by: (1) a map of all the tectonic elements making up the Limone-Viozene Zone and the Refrey Unit, which represent the south-eastern portion of a major regional transfer zone developed at the southern termination of the Western Alps arc; (2) the representation of km-scale Cretaceous palaeoescarpments previously overlooked or interpreted as Alpine faults; (3) a new interpretation of some dark shales with interbedded sandstones, which were previously mapped as Helminthoides Flysch tectonic remnants, as belonging to the Annot Sandstone unit, the uppermost term of the Alpine Foreland Basin succession; and (4) a map legend designed following the same criteria of the 1:250,000 Map of the Piemonte Region.