Lodge_NWOMMS_Apr3,2013

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VMS potential of the Shebandowan Greenstone Belt: Robert Lodge Earth Resources & Mapping Section, Ontario Geological Survey VMS potential of the Shebandowan Greenstone Belt. Presentation Summary: Regional Setting of the Shebandowan Belt Distribution of Volcanogenic Massive Sulphides (VMS) mineralization and formation of VMS deposits. Based on the regional lithogeochemistry, VMS potential of the Archean Shebandowan Greenstone Belt and spatial analysis of regional-scale VMS characteristics, allows a comparison with other Wawa greenstone belts. Talk April 3, 2013 by Robert Lodge (Ontario Geological Survey).

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By: andyfyon (53 month(s) ago)

Txs - much appreciated.

 

By: akashbathla (53 month(s) ago)

Hi Andy, this presentation is now featured on authorSTREAM. Congratulations and keep up the great work! - Akash, authorSTREAM Tea

 

By: andyfyon (54 month(s) ago)

Txs..is thesis work in progress.

 

By: akashbathla (54 month(s) ago)

Very insightful study, Andy. Thanks for sharing!

Presentation Transcript

VMS potential of the Shebandowan Greenstone Belt:

Robert Lodge Earth Resources & Mapping Section, Ontario Geological Survey VMS potential of the Shebandowan Greenstone Belt

Presentation Summary:

Presentation Summary Regional Setting of the Shebandowan Belt Distribution of VMS mineralization Volcanogenic Massive Sulphides (VMS) Formation of VMS deposits Regional lithogeochemistry VMS Potential of the Shebandowan Belt Spatial analysis of regional-scale VMS characteristics Comparison with other Wawa greenstone belts

PowerPoint Presentation:

Stott et al, 2010 Geology of NW Ontario

Distribution of VMS (Cu-Zn-Pb):

Distribution of VMS (Cu-Zn- Pb ) Western Wawa greenstone belts have limited discovered VMS mineralization Shebandowan/Vermilion VMS <1.0 Mt Winston Lake/Manitouwadge VMS 65-70 Mt

Distribution of VMS (Cu-Zn-Pb):

Distribution of VMS (Cu-Zn- Pb ) What are the fundamental controls on the distribution of VMS mineralization within these belts? What makes the Shebandowan different than Winston Lake and Manitouwadge in terms of VMS productivity? Are there regions of the larger Shebandowan greenstone belt that are more prospective for VMS mineralization?

Shebandowan Greenstone Belt:

Shebandowan Greenstone Belt Western Wawa greenstone belts have limited discovered VMS mineralisation WINSTON LAKE MANITOUWADGE VMS Mineralization Wye Lake Vanguard Calvert-Stares Mud Lake

Shebandowan Greenstone Belt:

Shebandowan Greenstone Belt Wye Lake Zn-Cu rich massive/stringer sulphides ( Freewest Resources, 2005) Chlorite-garnet discordant alteration zones Vanguard Cu-Zn rich massive/stringer sulphides (Everett Resources, 2007) Extensive chlorite- sericite -carbonate alteration Calvert-Stares Zn-Au rich disseminated/massive sulphide (RJK Exploration, 2005) Abundant muscovite/ sericite , minor chlorite Mud Lake Zn-enriched cherty exhalite horizon (C. Farrow, 1993) Weakly sericite -carbonate altered host

PowerPoint Presentation:

Wye Lake Zn-Cu Prospect

PowerPoint Presentation:

Mud Lake Zn-Mineralization

Volcanogenic Massive Sulphides (VMS):

Volcanogenic Massive Sulphides (VMS) From Galley (1993), Franklin (1996) and Franklin et al. (2005)

VMS Environments:

VMS Environments Galley et al, 2007

VMS Environments:

VMS Environments Where are the ideal VMS environments?

Mafic Rock Geochemistry:

Mafic Rock Geochemistry

Felsic Rock Geochemistry:

Felsic Rock Geochemistry (Hart et al, 2004) VMS VMS

Basic VMS Checklist:

Basic VMS Checklist Extensional Tectonic Setting Back-arc to MORB mafic rocks Heterolithic volcanic breccias High-level Synvolcanic Intrusions Similar ages for intrusion/volcanism FII to FIII-type felsic rocks Hydrothermal Activity VMS-style alteration (Na-Ca loss, Fe-Mg gain) Deep-Water Deposition Difficult to prove/disprove because of variety of volcanic deposits

Shebandowan VMS??:

Shebandowan VMS?? Extensional Tectonic Settings Back-Arc to MORB Heterolithic Volcaniclastic Rocks

VMS Environments:

VMS Environments Heterolithic Debris Flow

PowerPoint Presentation:

Haines Gabbroic Complex 2720 Ma FII-type Felsic Volcanic Rocks Shebandowan VMS?? High-level Synvolcanic Intrusions

VMS Environments:

VMS Environments FII-Type Felsic Tuff

PowerPoint Presentation:

Epidote-Quartz Alteration Chlorite Alteration Sericite Alteration Shebandowan VMS?? Hydrothermal Activity (Alteration)

VMS Environments:

VMS Environments Chlorite Alteration (w/ garnet)

VMS Environments:

VMS Environments Chlorite-Garnet Altered Dacite Tuff

VMS Environments:

VMS Environments Epidote-Quartz Altered Mafic Flow

PowerPoint Presentation:

Highly Amygdaloidal Flows & Breccias Accretionary Lapilli Shebandowan VMS?? Deep Water Deposition Mature Arc-like Deposits

PowerPoint Presentation:

(Back-arc) Highly Amygdaloidal Basalt

PowerPoint Presentation:

Dacite Accretionary Lapilli Tuff

VMS Environments:

VMS Environments Arc-like, FI-Type; Pumaceous Lapilli Tuff

VMS Environments:

VMS Environments Arc-like, FI-Type; Dacite Autobreccia

Evaluation of VMS Potential:

Evaluation of VMS Potential Highest VMS Potential Good VMS Potential Known VMS Prospect Local Areas of Interest

Summary:

Summary Compilation and strategic geochemical sampling through Shebandowan belt has highlighted regions that have the highest VMS-potential Spatial association between back-arc mafic rocks, FII-type felsic rocks, and synvolcanic intrusions: Favourable for VMS mineralization Predominately in the western part of the belt Vanguard & Wye Lake prospects are Zn-Cu, high temperature VMS mineralization Arc-like mafic rocks and FI-type felsic rocks suggest more mature arc setting: Not as favourable for VMS mineralization Predominately in the eastern part of the belt Calvert-Stares has boiling-type Zn-Au mineralization and alteration. Mud Lake has very limited alteration.

Summary:

Summary Winston Lake and Manitouwadge belts are interpreted to represent rifting arcs transitioning to back-arcs. Dominance of FIII-type felsic volcanic rocks Transition from calc-alkalic basalts to tholeiitic back-arc basalts Shebandowan has more characteristics of a mature arc with separate mature back-arc. This may explain the difficulty in finding ideal VMS environments. Dominance of FI-type felsic volcanic rocks, abundant andesite-dacite Calc-alkalic basalts in the east. Western basalts have rift-type characteristics, but have more (relatively) shallow-water indicators.

Data Release:

Data Release The results and regional interpretations from this study will be released as a Miscellaneous Release – Data ( MRD 306 ) in June, 2013 (tentatively) . Sample Info Geochemistry Nd-Pb Isotopes Geochronology All in ArcGIS format

Acknowledgements:

Acknowledgements Harold Gibson (Laurentian University) Greg Stott (OGS, Retired) Dorothy Campbell (OGS) John Scott (OGS, Retired) Jim Franklin (Consultant) OGS Assistants

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