ABSTRACT

The range of petrographic variability within a single turbidite is approximately as extensive as the range of mineralogical and textural variations observed between the base and top of a 250-m section of Annot Sandstones in the Lac d'Allos region of the French Maritime Alps. The same minerals are found throughout the vertical section of this flysch, indicating that source areas and weathered parent rock materials remained the same during the period of this formation's history. However, notable variations within and between succeeding turbidites are noted. Each suspension flow was characterized by its own specific density and velocity gradient, and, as a result, differing proportions of particle sizes settled out of each current passing over the same spot of the basin floor. Although s cceeding turbidity currents are able to transport similar sedimentary materials from nearshore environments into the deeper basin, quantitative variations of the type observed in this study should be expected in any formation comprising turbidites.