Earth Sciences Report 2003-01 Stratigraphy and Sedimentology of the Athabasca Group in the Net Lake-Maybelle River Area, Northeastern Alberta Alberta Energy and Utilities Board Alberta Geological Survey EUB/AGS Earth Sciences Report 2003-01 Stratigraphy and Sedimentology of the Athabasca Group in the Net Lake–Maybelle River Area, Northeastern Alberta R.T. Post1 1Formerly of Alberta Geological Survey (see page ii for current address) December 2004 ©Her Majesty the Queen in Right of Alberta, 2004 ISBN 0-7785-1513-3 The Alberta Energy and Utilities Board/Alberta Geological Survey (EUB/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 digital data and software supplied with this publication are subject to the licence conditions (specifi ed in ‘Licence Agreement for Digital Products’). The data are supplied on the understanding that they are for the sole use of the licensee, and will not be redistributed in any form, in whole or in part, to third parties. Any references to proprietary software in the documentation, and/or any use of proprietary data formats in this release, do not constitute endorsement by the EUB/AGS of any manufacturer’s product. If this product is an EUB/AGS Special Report, the information is provided as received from the author and has not been edited for conformity to EUB/AGS standards. When using information from this publication in other publications or presentations, due acknowledgment should be given to the EUB/AGS. The following reference format is recommended: Post, R.T. (2004): Stratigraphy and sedimentology of the Athabasca Group in the Net Lake–Maybelle River area, northeastern Alberta; Alberta Energy and Utilities Board, EUB/AGS Earth Sciences Report 2003-01. Author address: R.T. Post 7365 Baldwin Street, N Brooklin, Ontario L1M 1Y3 E-mail: [email protected] Published December 2004 by: Alberta Energy and Utilities Board Alberta Geological Survey 4th Floor, Twin Atria Building 4999 – 98th Avenue Edmonton, Alberta T6B 2X3 Canada Tel: (780) 422-3767 (Information Sales) Fax: (780) 422-1918 E-mail: [email protected] Web site: www.ags.gov.ab.ca EUB/AGS Earth Sciences Report 2003-01 (December 2004) • ii Contents Acknowledgments ......................................................................................................................................... v Abstract ....................................................................................................................................................... vi 1 Introduction ............................................................................................................................................ 1 1.1 Location of Study Area .................................................................................................................... 1 1.2 Methodology .................................................................................................................................... 1 1.3 Previous Work .................................................................................................................................. 1 2 Overview of the Regional Geology ....................................................................................................... 5 2.1 Basement Lithology ......................................................................................................................... 5 2.2 Athabasca Group .............................................................................................................................. 6 2.2.1 Fair Point Formation ............................................................................................................. 6 2.2.2 Manitou Falls Formation ....................................................................................................... 8 2.2.3 Lazenby Lake Formation .......................................................................................................8 2.2.4 Wolverine Point Formation ................................................................................................... 8 2.2.5 Locker Lake Formation ......................................................................................................... 8 2.2.6 Otherside Formation .............................................................................................................. 9 2.2.7 Points Lake Subgroup ...........................................................................................................9 2.3 Structural Features of the Western Athabasca Basin ....................................................................... 9 3 Stratigraphy of the Southwest Athabasca Basin in Northeastern Alberta .....................................10 3.1 Basement ........................................................................................................................................ 13 3.2 Stratigraphic Examination of the Fair Point Formation .................................................................14 3.2.1 Lithofacies Association 1: Siltstone .................................................................................... 14 3.2.2 Lithofacies Association 2: Pebble Conglomerate and Pebbly Sandstone ........................... 17 3.2.3 Lithofacies Association 3: Massive Sandstone ................................................................... 17 3.2.4 Petrography of the Fair Point Formation .............................................................................19 3.3 Stratigraphic Examination of the Manitou Falls Formation .......................................................... 19 3.3.1 Lithofacies Association 4: Crossbedded, Medium- to Coarse-Grained Sandstone .............19 3.3.2 Lithofacies Association 5: Intraclast-Bearing, Rippled, Medium-Grained Sandstone ....... 21 3.3.3 Petrography of the Manitou Falls Formation ...................................................................... 21 3.4 Stratigraphic Examination of the Lazenby Lake Formation ..........................................................22 3.4.1 Lithofacies Association 6: Pebble-and Granule-Bearing, Rippled and Massive Sandstone 22 3.4.2 Petrography of the Lazenby Lake Formation ......................................................................22 3.5 Paleozoic ........................................................................................................................................ 22 4 Diagenesis and Other Postdepositional Characteristics ...................................................................24 Discussion .................................................................................................................................................. 26 5.1 Depositional Model ........................................................................................................................ 26 5.1.1 Fair Point Formation ...........................................................................................................26 5.1.2 Manitou Falls Formation ..................................................................................................... 26 5.1.3 Lazenby Lake Formation .....................................................................................................26 5.2 Source Area .................................................................................................................................... 27 5.3 Tectonostratigraphic Model ........................................................................................................... 27 5.3.1 Sequence 1: Fair Point Sequence ........................................................................................ 28 5.3.2 Sequence 2: Manitou Falls Sequence .................................................................................. 28 EUB/AGS Earth Sciences Report 2003-01 (December 2004) • iii 5.3.3 Sequence 3: Lazenby Lake–Wolverine Point Sequence ..................................................... 31 5.4 Stratigraphy as an Exploration Guide ............................................................................................ 31 6 Conclusions ........................................................................................................................................... 31 6.1 Stratigraphic Revision of the Lower Athabasca Group ................................................................. 31 6.2 Depositional and Tectonic Implications .........................................................................................32 6.3 Economic Geology Implications ................................................................................................... 32 7 References ............................................................................................................................................. 33 Appendix 1 – Location, Stratigraphy and Drillhole Information for the Logged Cores ................... 39 Appendix 2 – Cross-Sections and Thickness Plots ................................................................................. 40 Appendix 3 – Petrography ....................................................................................................................... 46 Appendix 4 – Lithostratigraphic Breakdown of the Lower Athabasca Group ...................................50 Appendix 5 – Alteration and Replacement Features in the Lower Athabasca Group