Far-field correlation of palaeokarstic surfaces in Mississippian successions using high-frequency foraminiferal diversity trends

Abstract

The degree to which emergent surfaces are correlated in late Asbian carbonate successions in Britain and Ireland is assessed by the integration of detailed biostratigraphy and diversity trends in foraminifers. Data are related to the Trowbarrow Quarry section in northern England, which provides a reference section for the upper Asbian because of its rich assemblages and high sampling density. Diversity trends are shown to be non-random, possess cyclic behaviour, and can be quantitatively correlated between sections. The assemblages allow stratigraphic segmentation into 13 intervals of foraminiferal diversity trends, which sub-divide the coarser-resolution biozones and sub-biozones. Similar foraminiferal trends are recognised in sections hundreds of kilometres away from Trowbarrow, in South Wales, and southeastern and western Ireland, facilitating a more precise correlation of strata. These highlight the coeval nature of emergent surfaces and rhythms between these regions, thus, establishing a precise stratigraphy. This new assessment also enables better discrimination of ‘missing beats’ and large hiatuses in the successions. The establishment of this rhythmic stratigraphy permits recognition of the late occurrence of some biostratigraphical markers, enabling amendment of biostratigraphic mismatches.