THE MAGMATIC AFFINITIES OF THE DINANTIAN VOLCANISM OF SOUTHERN VOSGES(FRANCE) - GEOCHEMICAL APPROACH AND INTERPRETATION

Three units are present in the Dinantian volcanism from the southern V osges. The first, of Lower to Middle Visean age, is characterized by a n island arc tholeiite and a calc-alkaline association. The second, of early Upper Visean, is a high potassic calc-alkaline series; the thir d, of late Upper Visean age, is shoshonitic. All oceanic areas being c losed during the Devonian, it is difficult to associate this volcanism to an active subduction during early Carboniferous. Several hypothese s could be considered: ''posthumous'' influence of the Devonian subduc tion; genesis of this magmatism related to strike-slip fault basins in a collision setting; or within an ensialic ''Basin and Range'' type b asin.