ERCB/AGS Open File Report 2011-01 Review of Metallic Mineralization in Alberta with Emphasis on Gold Potential ERCB/AGS Open File Report 2011-01 Review of Metallic Mineralization in Alberta with Emphasis on Gold Potential A.S. Rukhlov Energy Resources Conservation Board Alberta Geological Survey January 2011 ©Her Majesty the Queen in Right of Alberta, 2011 ISBN 978-0-7785-8633-3 Energy Resources Conservation Board/Alberta Geological Survey (ERCB/AGS) and its employees and contractors make no warranty, guarantee or representation, express or implied, or assume any legal liability regarding the correctness, accuracy, completeness or reliability of this publication. Any software supplied with this publication is subject to its licence conditions. Any references to proprietary software in the documentation, and/or any use of proprietary data formats in this release, do not constitute endorsement by ERCB/AGS of any manufacturer’s product. If you use information from this publication in other publications or presentations, please give due acknowledgment to ERCB/AGS. We recommend the following reference format: Rukhlov, A.S. (2011): Review of metallic mineralization in Alberta with emphasis on gold potential; Energy Resources Conservation Board, ERCB/AGS Open File Report 2011-01, 93 p. Published in January 2011 by: Energy Resources Conservation Board Alberta Geological Survey 4th Floor, Twin Atria Building 4999 – 98th Avenue Edmonton, AB T6B 2X3 Canada Tel: 780.422.1927 Fax: 780.422.1918 E-mail: [email protected] Website: www.ags.gov.ab.ca ERCB/AGS Open File Report 2011-01 (January 2011) • iii Contents Acknowledgments........................................................................................................................................vi Abstract.......................................................................................................................................................vii 1 Introduction ............................................................................................................................................1 2 Methodology and Format .......................................................................................................................2 2.1 Data Compilation ..........................................................................................................................2 2.2 Mineral Occurrences and Geochemical Anomalies ......................................................................3 3 Geological Overview of Alberta ............................................................................................................7 3.1 Precambrian Basement and Athabasca Basin ...............................................................................7 3.2 Western Canada Sedimentary Basin ...........................................................................................12 4 Regional Structures ..............................................................................................................................15 4.1 Precambrian Structures ...............................................................................................................15 4.2 Phanerozoic Structures................................................................................................................16 4.2.1 Reactivated Faults ...........................................................................................................16 4.2.2 Paleozoic Arches and Hinges ..........................................................................................16 4.2.3 Other Structures...............................................................................................................18 5 Previous Regional Metallogenic Studies and Mineral Exploration in Alberta.....................................18 6 Placer Gold in Alberta..........................................................................................................................19 6.1 Historical Perspective..................................................................................................................19 6.2 Hypotheses of Origin ..................................................................................................................23 6.3 Future Potential ...........................................................................................................................25 7 Buried Placer or Paleoplacer Gold in Alberta ......................................................................................26 7.1 Historical Perspective..................................................................................................................26 7.2 Hypotheses of Origin ..................................................................................................................28 7.3 Future Potential ...........................................................................................................................30 8 Lode Gold in the Alberta Portion of the Canadian Shield....................................................................31 8.1 Historical Perspective..................................................................................................................31 8.2 Types of Mineral Occurrences and Hypotheses of Origin ..........................................................34 8.2.1 Stratiform and Shear Zone–Hosted Sulphides.................................................................34 8.2.2 Quartz-Tourmaline Veins................................................................................................35 8.2.3 Polymetallic Pegmatite and Iron-Oxide Breccias............................................................35 8.3 Future Potential ...........................................................................................................................36 9 Lode Gold in the Rocky Mountain Fold-and-Thrust Belt of Southwestern Alberta ............................37 9.1 Historical Perspective..................................................................................................................37 9.2 Types of Mineral Occurrences and Hypotheses of Origin ..........................................................48 9.2.1 Copper-Lead-Zinc Sulphides in Mafic Intrusions and Purcell Lavas..............................48 9.2.2 Sedimentary Exhalative Lead-Zinc-Copper-Silver Sulphides.........................................50 9.2.3 Stratiform, Black Shale–Hosted Zinc-Nickel-Molybdenum Sulphides ..........................51 9.2.4 Kupferschiefer/Redbed–Type Copper-Silver Sulphides .................................................51 9.2.5 Alkaline Intrusion–Related, Epithermal Gold-Silver-Copper-Lead-Zinc Mineralization .........................................................................................................................................53 9.2.6 Quartz-Carbonate Vein Copper-Lead-Zinc-Silver-Gold Mineralization.........................54 9.3 Future Potential ...........................................................................................................................55 10 Lode Gold in the Western Canada Sedimentary Basin of the Alberta Interior Plains..........................56 10.1 Historical Perspective..................................................................................................................56 10.2 Types of Mineral Occurrence and Hypotheses of Origin............................................................63 10.2.1 Ooidal Ironstone Polymetallic Deposits ..........................................................................63 10.2.2 Stratiform Exhalative Sulphide and Black Shale Polymetallic Mineralization...............63 10.2.3 Epigenetic, Sediment-Hosted, Microdisseminated Precious-Metal Mineralization........64 10.2.4 Alkaline Intrusion-Related, Epithermal Gold-Silver-Copper-Lead-Zinc Mineralization65 ERCB/AGS Open File Report 2011-01 (January 2011) • iv 10.3 Future Potential ...........................................................................................................................67 11 Conclusions ..........................................................................................................................................69 12 References ............................................................................................................................................70 Tables Table 1. Average chemical compositions of crustal materials......................................................................5 Table 2. Geochemical background values for selected rock types in Alberta ..............................................6 Table 3. Gold occurrences of the Precambrian shield in northeastern Alberta...........................................32 Table 4. Gold occurrences of the Rocky Mountain fold-and-thrust belt in southwestern Alberta. ............38 Table 5. Gold occurrences of the Alberta Interior Plains............................................................................57 Figures Figure 1. Simplified base map of Alberta.....................................................................................................4 Figure 2. Simplified bedrock geology of Alberta. ........................................................................................8 Figure 3. Major tectonic domains in the Precambrian crystalline basement. ...............................................9 Figure 4. Simplified geology of the Precambrian shield in northeastern Alberta.......................................11