Aspects of Upper Carboniferous nonmarine carbonate sedimentology in central England

El-Fiky, Abd El-aziz Mostafa

Abstract

The mid- to late-Westphalian C succession in central and northern England lacks typical marine bands but include various forms of thin, but widely extensive carbonates which appear at several stratigraphic levels, commonly overlying coal seams or interdigitating with the associated overbank and lacustrine mudstones. These carbonates include the well known sideritic blackband and clayband ironstones, the Spirorbis lacustrine and palustrine limestones and dolostones, and some calcretes. They coexist with red beds which tend to dominate the younger successions.

In this study, the term "blackband-type" ironstones is introduced to include all of the ironstones that overlie, or lie very close above coal seams, throughout the Westphalian. Based on petrographic, chemical and sedimentologic considerations, these ironstones are either suggested to replace original limestones (e.g. the typical blackband ironstones), orto be formed by reduction of original Fe compounds (e.g. the earlier Westphalian ironstones). In both cases the Fe is proposed to have migrated from lateritic sources outside the basin. The facies appear to have evolved progressively in relation to rates of sedimentation and/or subsidence, and the increasing development of red beds.

The Spirorbis lacustrine and palustrine limestones and dolostones are suggested to be initiated by brief marine transgressions following regional episodes of subsidence. They are biogenic in origin and were accumulated in progressively deepening lakes, in which high clastic supply may have terminated the carbonateforming processes. The latest Westphalian palustrine limestones were probably accumulated in widely extensive shallow wetland areas. The calcretes, on the other hand, show an increasing trend of maturity towards the late Westphalian.

It is suggested that many of the studied carbonates are genetically related and are comparable to those of the Dinantian in the Midland Valley of Scotland. The range of Westphalian carbonate forms may however be attributed to local factors.

Citation

El-Fiky, A. E.-A. M. (1998). Aspects of Upper Carboniferous nonmarine carbonate sedimentology in central England. (Thesis). Keele University. https://keele-repository.worktribe.com/output/1237044

• Thesis Type: Thesis
• Online Publication Date: May 13, 2025
• Deposit Date: May 13, 2025
• Publicly Available Date: May 13, 2025
• Keywords: Department of Earth Sciences.
• Public URL: https://keele-repository.worktribe.com/output/1237044
• Award Date: 1998-06