The Triassic system in the northern Calabria-Peloritani Orogen: evidence from basaltic dyke magmatism in the San Donato Unit

aBstract - Green to gray-green metabasite dykesoccur within the metasedimentary sequence of the sanDonato unit, the lowest tectonic unit cropping out inthe Mt. Pollino area (northern calabria). thesemetabasites are intruded in the anisian-ladinianmetasediments of the san Donato sequence, but not inthe overlying carnic levels, suggesting a Middletriassic emplacement age.the original porphyritic texture is locally preservedin weakly foliated samples affected by very low- tolow-grade metamorphism during the alpine orogeny.the metamorphic assemblages are indicative of apolyphase evolution: an early synkinematic albite +actinolite + chlorite + epidote + quarz + Fe-ti oxidesassociation developed at the subgreenschistgreenschistfacies transition, and a later albite + calcite+ chlorite + quartz +Fe-ti oxides mineral association,in microdomains and patches, suggests localisedincrease of Xco2 in the fluid phase.the protolith of the metabasites has been identifiedin alkaline to transitional basalts with geochemicalfeatures consistent with generation by partial meltingof an enriched mantle source in a within plate setting.in particular, their geochemical composition isconsistent with a low degree partial melting of aenriched mantle source. Based on geologicalconstrains and on petrological considerations, theseMiddle triassic metabasites may document the initialbreak-up stage of the Pangea, evolving to continentrifting and subsequent oceanization processes.