The 2.7–2.63 Ga Indin Lake Supracrustal Belt: An Archaean Marginal Basin–Foredeep Succession Preserved in the Western Slave Province, Canada

  1. Wladyslaw Altermann2 and
  2. Patricia L. Corcoran3
  1. S. J. Pehrsson

Published Online: 12 MAR 2009

DOI: 10.1002/9781444304312.ch6

Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems

Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems

How to Cite

Pehrsson, S. J. (2002) The 2.7–2.63 Ga Indin Lake Supracrustal Belt: An Archaean Marginal Basin–Foredeep Succession Preserved in the Western Slave Province, Canada, in Precambrian Sedimentary Environments: A Modern Approach to Ancient Depositional Systems (eds W. Altermann and P. L. Corcoran), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304312.ch6

Editor Information

  1. 2

    Institut für Allgemeine und Angewandte Geologie, Ludwig-Maximilians-Universität München, Luisenstrasse 37, D-80333 Munich, Germany

  2. 3

    Department of Earth Sciences, Dalhousie University, Halifax, Nova Scotia, B3H 3J5, Canada

Author Information

  1. Continental Geoscience Division, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, Canada

Publication History

  1. Published Online: 12 MAR 2009
  2. Published Print: 18 FEB 2002

ISBN Information

Print ISBN: 9780632064151

Online ISBN: 9781444304312

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Keywords:

  • archaean marginal basin–fore deep succession preserved in western Slave Province, Canada;
  • Slave Province of north-western Canadian Shield - composite granite-greenstone terrane of volcano-sedimentary belts;
  • stratigraphy and physical volcanology;
  • Leta Arm group - heterogeneous package of mafic to felsic volcanic rock;
  • Syn-2670 Ma - Leta Arm group;
  • 2647–2629 Ma - Chalco Lake group;
  • comparison with modern environments

Summary

The 2.7–2.63 Ga Indin Lake supracrustal belt contains the sedimentary record of a relatively juvenile, Neoarchaean tectonostratigraphic sequence unique to the south-western part of the Slave Province, Northwest Territories, Canada. Yellowknife Supergroup rocks of the belt comprise three distinct lithostratigraphic groups. The basal, >2.67 Ga, Hewitt Lake group consists of homogeneous, pillowed mafic tholeiitic and lesser felsic calc-alkaline volcanic rocks, generated from effusive eruptions and syneruptive mass and sediment gravity flows on the flanks of moderately deep subaqueous shield volcanoes. The overlying c.2.67 Ga Leta Arm group includes pillowed and massive mafic to felsic flows and diverse intermediate to felsic reworked pyroclastic and volcanogenic epiclastic rocks, all characterized by abrupt lateral and vertical facies changes. It is interpreted to have largely formed from effusive eruptions and syneruptive mass flows on the medial flanks of moderate to shallow, originally locally emergent, marine stratovolcanoes. Both groups are interpreted to have formed on thinned, somewhat older, continental crust, based on the variety of interbedded siliciclastic facies, isotopic and geochemical characteristics and inherited zircon component. The unconformably overlying, <2.65 Ga Chalco Lake group, consisting of conglomerates, graded sandstone–mudstones and minor felsic and mafic volcanic rocks including peperites, was largely deposited from sediment gravity flows in a deep marine basin. The basin formed during compressional orogenesis in the southern Slave Province and contains detritus eroded from both its volcanic substrate and Mesoarchaean sialic crust. The lithostratigraphic record of the Indin Lake supracrustal belt is interpreted to reflect early establishment of a marginal basin–arc sequence on thinned Mesoarchaean crust and subsequent development of a marine, syncollisional foredeep basin. Textures, associations and facies of the various lithostratigraphic units are strikingly similar to those of similar modern day environments. The Hewitt Lake and Leta Arm groups, like modern arc–marginal basin systems, are dominated by products of submarine effusive eruptions, debris and sediment gravity flows. The deep water facies of the syncollisional Chalco Lake group are typical of modern, marine orogenic basins such as foredeeps or underfilled peripheral foreland basins. Association of bimodal magmatism with foredeep sedimentation, however, is a feature unique to the Precambrian. The quartz-rich nature of first-cycle sandstones derived largely from volcanic sources is thought to reflect aggressive chemical weathering in the humid, CO2-rich Archaean atmosphere. The predominance of mass and sediment gravity flows in these Neoarchaean sedimentary environments may be linked to high rates of erosion in a high relief, unvegetated terrain.