Phreatic sulphide bearing quartz breccias between crystalline basement and Collio formation (Southern Alps, Italy)

Diego Servida(*), Marilena Moroni(*), Daniele Ravagnani(**), Franco Rodeghiero (***), Ida Venerandi(*), Luisa De Capitani(*) & Giovanni Grieco(*)
(*) Università degli Studi di Milano, Dipartimento di Scienze della Terra «A. Desio», Via Botticelli, 23 - 20133 Milano (Italy), tel. 02/50315619, e-mail: ida.venerandi@unimi.it (**) GeoTer, Via Rossini, 2 - 24020 Ardesio (BG, Italy). (***) Università degli Studi di Milano Bicocca, Dipartimento di Scienze Geologiche e Geotecnologie - Piazza della Scienza, 4 - 20126 Milano (Italy).

In this work a report is given of the geological, petrographic and ore mineralogical features of several sulphide-bearing quartz breccias (SQB) bodies outcropping in a structurally complex sector of the Orobic Alps (Southern Alpine domain) and close to the uranium-rich mining area of Novazza. Although little studied, these breccia bodies were previously attributed to different genetic processes and/or geological domains (e.g., Crystalline Basement, Basal Conglomerate formation). The features of the SQB bodies suggest a hydrothermal origin likely related to the large-scale hydrothermal process causing the formation of the nearby uranium ore deposit at Novazza.

Phreatic breccia, hydrothermal activity, Orobic Alps, Novazza, quartz, sulphides.