PALAEOCENE STRATIGRAPHY OF THE LONDON BASIN: AN INTEGRATED APPROACH

Limited onshore preservation and poor exposure quality have restricted the extent to which a detailed stratigraphy can be established for the English Palaeocene. This problem is further compounded by the prevalence of intense bioturbation, the interdigitation of facies across the basin and the recurrence of similar facies within the sequence. Fortunately, given the paucity of good exposures, the British Geological Survey preserves extensive core data which can usually be sampled. This paper presents a high-resolution stratigraphy derived from data extracted from such samples, in addition to those taken from the few existing exposures. Transgressive strata have been traced across the basin and provide a framework for the correlation of finer sediments. Palaeoenvironments have also been inferred, representing a range of settings from terrestrial through to marine.

The techniques used in this study were: grain-size analysis, heavy mineral analysis, tourmaline geochemistry and the examination of quartz-grain surface features. These analyses have proven highly complementary and tend to reinforce and clarify one another. For example, the grain-size and heavy mineral analyses have both been used to pick out relatedness patterns and multiply-sourced sediments. Conversely, the heavy mineral and quartz-grain surface feature analyses both provide evidence of grain transport, reworking and diagenetic history. The combination of such techniques particularly aids the distinction of the various causes of mineralogical variation in an assemblage (for example: varying provenance or diagenesis). These results indicate that such multi-faceted studies of core-derived material can significantly improve our understanding of poorly preserved and unstructured strata, despite the restrictions of small sample size and limited core distribution.