Fluid Inclusions of Auriferous Quartz Veins from Harrigan Cove, Nova Scotia

Abstract

<p> The Meguma Group is situated in the southeastern and southwestern regions of Nova Scotia. The Meguma Group is divided into two formations: the Goldenville and the Halifax. Both formations are comprised of A and E divisions of the Bouma sequence. Thus, the Meguma Group is a turbidite deposit. Auriferous quartz veins strike parallel to bedding and occur between the lower Bouma cycle's E division and the overlying Bouma cycle's A division. The development of bedding-parallel veins was due to hydraulic fracturing of the Bouma units.</p> <p> The bedding-parallel quartz veins were emplaced at low temperatures, from 260°C to 300°C. The fluid which precipitated the gold-arsenopyrite-quartz veins consisted of a divalent cation salt species (MgCl2) and hydrosulphide ligands which were the main complexing agent of gold.</p> <p> Gold was precipitated due to the reduction of sulphide ligands as they came into contact with the organic-rich slates of the E division of the Bouma sequence. Sulphide reduction was not complete, thus a large concentration of gold remained in solution later to be precipitated with arsenic in arsenopyrite.</p>