Nitrogen distribution in Lower Palaeozoic slates/phyllites of the Meguma Supergroup, Nova Scotia, Canada: implications for Au and Zn-Pb mineralisation and exploration

Major and trace elements and nitrogen were analysed in 59 Cambrian and Ordovician slates/phyllites of various lithostratigraphic levels within the Meguma Supergroup, 14 Ordovician slates/phyllites of The Ovens gold mineralisation, and 16 Ordovician slates/phyllites of the Eastville Pb-Zn-Cu mineralisation. The fixed nitrogen content and the normative N-fix/K2O ratio of muscovite separates members of the Goldenville (sandstone-greywacke-quartzite dominated) and Halifax Formation (slate-phyllite dominated). Low fixed nitrogen concentration is related to high manganese concentration. Black slates/phyllites of the saddle-reef-type Au-mineralisation in The Ovens area are characterised by high fixed nitrogen and a high normative Nfix/K2O ratio of muscovite. The nitrogen is of secondary hydrothermal origin. Therefore, it might be possible to use the fixed nitrogen as an exploration tool for black slates/phyllite hosted gold mineralisation in Nova Scotia. Mineralised slates/phyllites of the Eastville stratabound Pb-Zn mineralisation cannot be distinguished from nonmineralised time equivalent lithologies on the basis of the fixed nitrogen distribution or the N-fix/K2O ratio of muscovite. (C) 2002 Elsevier Science B.V. All rights reserved.