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Abstract

The Bardoc Tectonic Zone is an *80 km-long and up to 12 km wide, intensely sheared corridor of Late
Archaean supracrustal rocks that is bounded by pre- to syn-tectonic granites in the Eastern Goldfields
Province, Yilgarn Craton. This zone has produced over 100 t of gold from a range of deposits, the largest
being Paddington (*40 t Au). This shear system is connected along strike to the Boulder – Lefroy Shear
Zone, which hosts considerably larger deposits including the giant Golden Mile Camp (41500 t
produced Au). In contrast to the diverse characteristics of gold deposits associated with the Boulder –
Lefroy Shear Zone, mineralogical and geochemical data from five representative localities in the
Bardoc Tectonic Zone have relatively uniform features. These are: (i) quartz – carbonate veins
in competent mafic units with wall-rock alteration characterised by carbonateþ quartzþmuscoviteþchlorite+biotiteþsulf-arsenideþsulfideþoxideþgold assemblages; (ii) arsenopyrite
as the dominant sulfur-bearing mineral; (iii) a unique three-stage paragenetic history,
commencing with pyrrhotite, and progressing to arsenopyrite and then to pyrite-dominated alteration;
(iv) a lack of minerals indicative of oxidising conditions, such as hematite and sulfates; (v) d34 sulfur
compositions of pre- to syn-gold iron sulfides ranging from 1 to 9%; and (vi) a lack of tellurides. These
features characterise a coherent group of moderately sized orogenic-gold deposits, and when
compared with the larger gold deposits of the Boulder – Lefroy Shear Zone, potentially highlight the
petrological and geochemical differences between high-tonnage and smaller deposits in the Eastern
Goldfields Province.

Item Type:	Article
Authors/Creators:	Morey, AA and Weinberg, RF and Bierlein, FP and Davidson, GJ
Keywords:	Archaean, Bardoc Tectonic Zone, hydrothermal alteration, orogenic gold, sulfur isotopes, Yilgarn Craton.
Journal or Publication Title:	Australian Journal of Earth Sciences
ISSN:	0812-0099
DOI / ID Number:	10.1080/08120090701392671
Additional Information:	The definitive published version is available online at: http://www.tandf.co.uk/journals
Item Statistics:	View statistics for this item

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