Structural-geological field-mapping of the south-western flank of the Aspromonte Massif and the metamorphic zonation of the Stilo Unit (southern Calabria -Italy) via a GIS database

The structural-geological field survey (topographic base at 1:10000 scale) of the south-western part of the Aspromonte Massif (southern Calabria) clearly demonstrates the imbrication of three main tectono-metamorphic units by means of tectonic contacts developed at various crustal depth discernible in the field by the occurrence of cataclastic to mylonitic rocks marking the thrust planes. These three units, characterized by distinct deformational history and peculiar PT paths, are from top to bottom: the Stilo Unit (SU), the Aspromonte-Peloritani Unit (APU) and the Madonna di Polsi Unit (MPU), which includes those metapelites surfacing into three main tectonic windows named "Polsi", "Cardeto" and "Samo-Africo" from the most important localities occurring nearby.The collection via a GPS device of a large number of samples (hundreds of oriented specimens) from the different outcropping tectono-metamorphic units allowed us to organize all derivative information (such as spatial orientation of structural features, bulk chemical analyses, thin-sections pictures, mineral assemblages, electron-probe microanalyses) into a GIS database.Similar records (e.g. mineral occurrences) within the whole GIS database with precise geographic coordinates can be plotted separately permitting to obtain derivative maps such as the metamorphic zonation of the Stilo Unit. This unit, made up of low greenschist- to low amphibolite-facies Palaeozoic metamorphic rocks, lies through a brittle tectonic contact over the Aspromonte-Peloritani Unit (APU), which is made up of amphibolite-facies metamorphic rocks intruded by late Hercynian peraluminous both locally overprinted by Alpine type metamorphism which developed at about 36-220 Ma. The petrographic-derived metamorphic zonation chart here presented has been created after the detailed petrographic analysis of about 80 thin sections and the recognition of mineral assemblages of a thermal metamorphic aureole (biotite, muscovite and andalusite blastesis) produced by Late Hercynian magmatic bodies intruded into metapelites (Punta d'Atò granitoids, outcropping in the northern part of the mapped area).