Subaqueous Clastic Fissure Eruptions and other Examples of Sedimentary Transposition in the Lacustrine Horton Bluff Formation (Mississippian), Nova Scotia, Canada

  1. Albert Matter and
  2. Maurice E. Tucker
  1. Reinhard Hesse1 and
  2. Harold G. Reading2

Published Online: 29 JUN 2009

DOI: 10.1002/9781444303698.ch13

Modern and Ancient Lake Sediments

Modern and Ancient Lake Sediments

How to Cite

Hesse, R. and Reading, H. G. (1978) Subaqueous Clastic Fissure Eruptions and other Examples of Sedimentary Transposition in the Lacustrine Horton Bluff Formation (Mississippian), Nova Scotia, Canada, in Modern and Ancient Lake Sediments (eds A. Matter and M. E. Tucker), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444303698.ch13

Author Information

  1. 1

    Department of Geological Sciences, McGill University, Montreal, Canada

  2. 2

    Department of Geology and Mineralogy, Oxford University, UK

Publication History

  1. Published Online: 29 JUN 2009
  2. Published Print: 24 NOV 1978

ISBN Information

Print ISBN: 9780632002344

Online ISBN: 9781444303698

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Keywords:

  • element of Late Palaeozoic- Early Mesozoic continental deposits;
  • intrastratal viscous or hydroplastic flow;
  • Horton Bluff Formation;
  • presence of non-marine fauna and absence of marine fossils;
  • Dykes associated with subaqueous clastic fissure eruptions

Summary

In the lower Mississippian lacustrine Horton Bluff Formation of Nova Scotia remarkable examples of sedimentary transposition structures occur. Transposition structures are secondary sedimentary structures that result from intrastratal viscous or hydroplastic flow. These include intermediate-sized circular and elliptical collapse structures associated with sediment extrusion from adjacent fissure vents and a swarm of more than 100 parallel clastic dykes, many of which show evidence for extrusion at the sediment surface. The dykes are strongly folded suggesting very early diagenetic initiation of intrastratal sediment movement.

The Horton Bluff Formation is made up of dark-grey to black and greenish-grey shale alternations grouped into sequences. The greenish-grey shale divisions contain fossil soil horizons (mainly in their upper parts). Signs of temporary emergence (mud-cracks, isolated tree stumps) are also found in the dark-grey shale division. Lithology, fossil content and association with fluvial deposits below and above suggest a lacustrine origin.

The formation of the transposition structures is attributed to contemporaneous Mississippian earthquake activity in the neighbourhood of the Mississippian rift of Nova Scotia. Similar structures found elsewhere may therefore indicate palaeoseismicity and may be of help in evaluating the diagenetic history of sedimentary basins.

For an extended German abstract of this paper see Hesse (1976).