Distribution and Lateral Variability of Heavy Minerals in the Annot Sandstones

Abstract

Petrographic studies of the Nummulitic Annot Sandstones in the French and Italian Maritime Alps have revealed that both the mineralogical and the textural composition of these rocks vary extensively laterally. The Annot Sandstones have been subdivided into three distinct but intergradational lithofacies on the basis of detailed studies in the field and laboratory. These consist of flysch facies in the Northern Zone, a non-flysch facies in the Southern Zone, and a transitional facies in the Intermediate Zone between the Northern and Southern Zones. The heavy minerals of the marine Annot Sandstones in the Maritime Alps may be grouped into four major mineral associations, each association occupying a distinct geographic position. This distribution of heavy minerals supports the hypothesis that sediments were brought into the Nummulitic paleobasin from the south, east, and west.