Meander Bend Reconstruction from an Upper Mississippian Muddy Point Bar at Possum Hollow, West Virginia, USA

  1. N. D. Smith3 and
  2. J. Rogers4
  1. B. R. Turner1 and
  2. K. A. Eriksson2

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304213.ch26

Fluvial Sedimentology VI

Fluvial Sedimentology VI

How to Cite

Turner, B. R. and Eriksson, K. A. (2009) Meander Bend Reconstruction from an Upper Mississippian Muddy Point Bar at Possum Hollow, West Virginia, USA, in Fluvial Sedimentology VI (eds N. D. Smith and J. Rogers), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304213.ch26

Editor Information

  1. 3

    Department of Geosciences, 214 Bessey Hall, University of Nebraska, Lincoln, NE 68588-0340, USA

  2. 4

    Cape Town, South Africa

Author Information

  1. 1

    Department of Geological Sciences, University of Durham, Durham DH1 3LE, UK

  2. 2

    Department of Geological Sciences, Virginia Polytechnic and State University, Blacksburg, Virginia, 24061-0420, USA

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 7 OCT 1999

ISBN Information

Print ISBN: 9780632053544

Online ISBN: 9781444304213

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Keywords:

  • meander bend reconstruction from Upper Mississippian muddy point bar at Possum Hollow, West Virginia, USA;
  • sediment load carried by channel influences - channel morphology and depositional style;
  • sensitive high resolution microprobe (SHRIMP);
  • measured section and environmental interpretation of Upper Mississippan Hinton Formation exposed in Possum Hollow road-cut;
  • Possum hollow succession;
  • meander bend reconstruction;
  • genetic packages

Summary

The terrestrial to shallow-marine Hinton Formation (Upper Mississippian) exposed at Possum Hollow, West Virginia, contains laterally accreted point-bar deposits, which overlie a vertic palaeosol and are capped by marine transgressive deposits. These form part of an unconformably bounded 3–5 Myr sequence, controlled by a third-order eustatic cycle and/or tectonic loading, in which the palaeosol and point bar are interpreted as the up-dip equivalent of a fourth-order base-level rise expressed in down-dip areas by tidal estuarine successions. The scoured base of the point bar is overlain by a channel lag conglomerate that passes sharply upwards into centimetre to decimetre thick, sandstone–mudstone couplets forming individual lateral accretion units. These couplets differ from those in tidal channels in that the mud-rich part is thicker, their thickness and frequency is less regular, and there is less separation of sand and clay. Dip variations along individual accretionary surfaces define bounding surface discontinuities, which enclose flood-generated couplets of broadly similar shape. The bounding surface discontinuities allow the point bar to be divided into six genetic packages, which are attributed to normal variations in flood discharge and channel bend migration, possibly linked to changes in meander bend dimensions. Meander bend reconstruction, based on interpretation of genetic packaging of strata, suggests that the point bar and channel bend evolved through time as follows:

1 the initial channel had a relatively low width:depth ratio and low transverse bar slopes;

2 the overall channel width increased, point bar platforms developed and meander bend curvature decreased;

3 short-term decrease in channel width:depth and increased suspension load;

4 increased width:depth and lower radius of meander bend curvature;

5 erosion and increased energy levels (?major flood) or relocation of the point bar into a higher energy part of the meander bend;

6 decreased width:depth and increased mud content consistent with abandonment.