The Environmental Setting of Early Carboniferous Mud-Mounds
- C. L. V. Monty,
- D. W. J. Bosence,
- P. H. Bridges and
- B. R. Pratt
Published Online: 14 APR 2009
Copyright © 1995 The International Association of Sedimentologists
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
- Published Online: 14 APR 2009
- Published Print: 17 JUL 1995
Print ISBN: 9780865429338
Online ISBN: 9781444304114
- 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
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.