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TitleInterpretations and implications of preliminary LA ICP-MS analysis of chert for the origin of geochemical signatures in banded iron-formations (BIFs) from the Meadowbank gold deposit, Western Churchill Province, Nunavut
AuthorGourcerol, B; Thurston, P C; Kontak, D J; Côté-Mantha, O
SourceGeological Survey of Canada, Current Research (Online) no. 2014-1, 2014, 26 pages, (Open Access)
PublisherNatural Resources Canada
Mediaon-line; digital
File formatpdf
NTS56D/11; 56D/12; 56D/13; 56D/14; 56E/03; 56E/04; 56E/05; 56E/06; 66A/09; 66A/10; 66A/15; 66A/16; 66H/01; 66H/02; 66H/07; 66H/08
AreaTehek lake; Meadowbank
Lat/Long WENS-97.0000 -95.0000 65.5000 64.5000
Subjectseconomic geology; geochemistry; mineral deposits; mineral occurrences; gold; mineralization; iron formations; analytical methods; electron microscopy; mass spectrometer analysis; hydrothermal deposits; volcanic rocks; sedimentary rocks; metamorphic rocks; metamorphism; deformation; Churchill Province; Meadowbank Deposit; Rae Domain
Illustrationslocation maps; graphs
ProgramTargeted Geoscience Initiative (TGI-4), Gold Ore Systems
Released2014 05 09
AbstractThis 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 footprint 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.
Summary(Plain Language Summary, not published)
This document presents preliminary results from the characterization of the primary chemical composition of finely laminated iron-rich sedimentary strata formed in a submarine environment, called banded iron formations, from the Meadowbank area in Nunavut. Some of these formations are hosts to gold mineralization and others are not. The objective is to differentiate mineralized from non-mineralized banded iron formations by defining their chemical signature, and to establish the chemical signature of mineralized formations. In this report we concentrate on the chemical signature of silica-rich interlayer associated with the iron rich bands, which was established using in-situ, microscopic scale analysis. Preliminary results indicate that the banded iron formations have a mixed signature inherited from seawater, hot fluids expelled on the sea floor, and from the rocks on which the formation was deposited. The signature varies depending on the presence of gold or its absence, suggesting that ore-bearing banded iron formations can be fingerprinted.