Abstract:

This project is designed to establish if there is a distinctive geochemical signature for the types of banded iron-formations (BIF) that contain gold mineralization and whether a hydrothermal foot- print for the mineralization can be detected. Herein are reported the preliminary geochemistry results of a LA ICP-MS study of 39 chert samples for BIFs from the Meadowbank deposit in the Rae Domain of western Churchill Province where gold mineralization is associated with several Algoma-type BIFs within the Neoarchean Woodburn Lake Group. The main deposit is located in the Central BIF, which has been in production since 2010 with 24.5 Mt proven/probable ore reserves grading 2.8 g/t (2011). Recently, mineralization has also been identified associated with BIFs in the Far West, West, East and Grizzly zones. The geochemistry of the cherts from these five BIFs, as determined from line traverses of chert using the in situ LA ICP-MS method, has identified an ambient seawater signature (characterized by enrichment in HREE relative to LREE, positive La, Gd, and Y anomalies) and a hydrothermal signature (characterized by a positive Eu anomaly), with some influence of crustal contamination.