Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Exploration and Mining Geology Signup for GSW Email News
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Exploration and Mining Geology; July 2006; v. 15; no. 3-4; p. 155-176; DOI: 10.2113/gsemg.15.3-4.155
© 2006 Canadian Institute of Mining, Metallurgy & Petroleum
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by WALKER, J.A.
Right arrow Articles by McCLENAGHAN, S.H.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

The Orvan Brook Volcanogenic Massive Sulfide Deposit: Anatomy of a Highly Attenuated Massive Sulfide System, Bathurst Mining Camp, New Brunswick

J.A. WALKER1, D.R. LENTZ2 and S.H. McCLENAGHAN2

1 New Brunswick Department of Natural Resources, Geological Surveys Branch, P.O. Box 50, Bathurst, New Brunswick, E2A 3Z1.
2 Department of Geology, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, E3B 5A3.

The Orvan Brook deposit is one of several (Zn+Pb>>Cu)-rich sulfide deposits hosted by the Spruce Lake Formation (California Lake Group) in the northwestern part of the Bathurst Mining Camp. This parautochthonous deposit is hosted by a narrow band of highly deformed, locally graphitic shale that appears to conformably overlie felsic volcanic rocks of the Spruce Lake Formation, and is in tectonic contact with overlying mafic volcanic and related sedimentary rocks of the Canoe Landing Lake Formation.

The Spruce Lake Formation is dominated by felsic volcanic rocks and subordinate fine-grained sedimentary rocks, and mafic volcanic rocks (Canoe Landing Lake member). The felsic volcanic rocks can be divided into aphyric and feldspar-phyric rock types. The feldspar-phyric rocks and a few of the aphyric varieties have a Zr/TiO2 ratio of 0.06, and fall into the California Lake Group field on a Y/TiO2 versus Zr/TiO2 diagram. In contrast, the aphyric felsic volcanic rocks have Zr/TiO2 {approx} 0.09 and are marked by high Zr and Th, which is consistent with highly fractionated felsic magma of Spruce Lake affinity. Major and trace element analyses of host rocks suggest that weak to moderate hydrothermal alteration developed on the south side (stratigraphic footwall) of the deposit, which is consistent with a north-younging succession.

The sulfide lens strikes east-west for approximately 2.3 km, extends down-dip for at least 500 m locally, and has an average thickness of between 0.75 and 1 m, but is locally up to 5.5 m thick. The contacts of the massive sulfide lens with its host rocks are invariably sharp. Host rocks show evidence of intense ductile deformation as well as later brittle deformation. Compositional layering and sulfide breccia textures in the sulfide body are interpreted to result from deformation or tectonic enhancement of original primary layering. The deposit contains an estimated resource of 2.69 Mt grading 1.73% Pb, 5.95% Zn, 0.37% Cu, 72 g/t Ag, and 0.9 g/t Au. Similarities in bulk {delta}34S between the Orvan Brook (+8.6{per thousand}) and the nearby Cu-rich McMaster deposit (+8.2{per thousand}) suggest a common depositional setting.

Key Words: Massive sulfide deposit • Sulfide gneiss • Lithogeochemistry • Orvan Brook • Bathurst Mining Camp






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Canadian Institute of Mining, Metallurgy & Petroleum