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Non-Marine and Paralic Sequences |
Postgraduate Research Institute for Sedimentology, The University of Reading, PO Box 227, Whiteknights, Reading RG6 2AB, UK
Palaeosols (fossil soils) are common in ancient shallow marine carbonate successions. The degree of development exhibited by the palaeosol reflects the duration of subaerial exposure, with palaeosols occurring at lower order sequence boundaries commonly showing complex, polygenetic histories, and those at higher order boundaries showing less development. Palaeosols in parasequence sets commonly display systematic variations in their degrees of development reflecting the varying lengths of subaerial exposure related to changes in accommodation space creation. These properties of palaeosols can be used to reappraise the sequence stratigraphical positions of peritidal carbonates in the Lower Carboniferous of southwest Britain, serving to illustrate the dangers of assigning facies units to systems tracts based solely on simple facies relationships. The palaeosols and associated sequences do not support the view that high frequency, moderate amplitude eustatic sea-level fluctuations of Milankovitch-type were operating during the Tournaisian or early Viséan.
