Mineralogy, petrography and evolution of Triassic magmatites of the Cima Pape Complex, eastern Dolomites

Middle Triassic magmatic products in the Cima Pape area (Eastern Dolomites) are examined. Stratigraphically the volcanic rocks are placed between the Livinallongo formation and the "Conglomerato della Marmolada' formation. The succession starts with the "agglomerati' (a tabular sheet of chaotic deposits derived from submarine slidings) followed by pillow lavas, pillow breccias and small subvolcanic bodies. A thick hyaloclastite sequence marks the end of volcanic activity. A sill varying in thickness from 50 to 300 m is injected inside the Livinallongo formation and controls the distribution of the overlying volcanics. The sill has undergone important differentiation. The chemical characteristics of the volcanic rocks show a clear affinity with shoshonitic series. The rocks could be derived from high alumina basalt primary magmas by high-pressure fractional crystallisation near the base of a thick crust. The "Conglomerato della Marmolada' is a thick conglomeratic sequence made almost exclusively of volcanic elements. This formation marks the end of an upper-Ladinian tectonic phase with extensive uplifting, faulting and erosions. -from English summar