The Environmental Setting of Early Carboniferous Mud-Mounds

  1. C. L. V. Monty,
  2. D. W. J. Bosence,
  3. P. H. Bridges and
  4. B. R. Pratt
  1. P. H. Bridges1,
  2. P. Gutteridge2 and
  3. N. A. H. Pickard3

Published Online: 14 APR 2009

DOI: 10.1002/9781444304114.ch6

Carbonate Mud-Mounds: Their Origin and Evolution

Carbonate Mud-Mounds: Their Origin and Evolution

How to Cite

Bridges, P. H., Gutteridge, P. and Pickard, N. A. H. (1995) The Environmental Setting of Early Carboniferous Mud-Mounds, in Carbonate Mud-Mounds: Their Origin and Evolution (eds C. L. V. Monty, D. W. J. Bosence, P. H. Bridges and B. R. Pratt), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304114.ch6

Author Information

  1. 1

    Division of Earth Sciences, University of Derby, Kedleston Road, Derby DE22 1GB, UK

  2. 2

    Cambridge Carbonates Ltd, 11 Newcastle Drive, The Park, Nottingham, NG7 1AA, UK

  3. 3

    Institute of Biology and Geology, University of Tromsø, Dramsveien 201, N-9037, Tromsø, Norway

Publication History

  1. Published Online: 14 APR 2009
  2. Published Print: 17 JUL 1995

ISBN Information

Print ISBN: 9780865429338

Online ISBN: 9781444304114

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Keywords:

  • environmental setting of early carboniferous mud-mounds;
  • fenestrate bryozoan-sponge spicule buildups;
  • crinoid-bryozoan buildups;
  • crinoid-brachiopod-fenestrate bryozoan buildups;
  • coredgal-Aphralysia and bryozoan-coralgal buildups;
  • trepostome-microthrombolite buildups

Summary

With the demise of framework-producing reef communities during the Frasnian, the transgressing seas of the Early Carboniferous were characterized by non-framework buildups. This study examines the environmental setting of these buildups which were dominated by carbonate mud-mounds. Given the lack of consistency with which the terms ‘Waulsortian’, ‘Waulsortianlike’ and ‘non-Waulsortian’ have been applied in the past, it is argued that descriptors based on skeletal composition should be used to distinguish types of buildup.

From a literature survey of Early Carboniferous buildups which formed on the south and south-west margin of Laurussia, five types of buildup are proposed. These are:

1 fenestrate bryozoan-sponge spicule buildups;

2 crinoid-bryozoan buildups;

3 crinoid-brachiopod-fenestrate bryozoan buildups;

4 coralgal-Aphralysia and bryozoan-coralgal buildups;

5 trepostome-microthrombolite buildups.

This series of buildups reflects a general decrease in water depth. Types 1, 3 and 5 are essentially microbial carbonate mud-mounds; only type 4 shows evidence of framework textures.

Type 1 buildups formed during the Courceyan to mid-Chadian stages and are associated with deep-ramp, basinal and shelf-slope environments. Type 2 formed in turbid mid-ramp environments. Type 3 buildups developed in intrashelf basins during the Holkerian–Brigantian stages. Type 4 occurred in mid-shelf and shelf-margin settings during the late Chadian to Asbian. Type 5 formed in coastal marine locations during the Asbian and Brigantian. Overall it appears that buildups shifted to shelf-margin and intrashelf basins as these environments became established in the Asbian and Brigantian.

While there is evidence for an association between type 5 buildups and hydrocarbon seeps, the deep-water and marginal setting of type 1 and type 3 buildups is best explained by the nutrient supply from regional upwelling.