Stratigraphic and spatial distribution of palynomorphs in deep-water turbidites: A meta-data study from the UK central North Sea paleogene

Abstract

The Paleogene Sele Formation spans across the basinal areas of the UK Central North Sea and comprises a very laterally extensive deep-marine fan system, namely the Forties Sandstone Member, a very important oil and gas reservoir horizon. The development of this turbidite system across the basin floor resulted from the response to sea-level changes and fluctuating sediment yield from the continental landmass influenced by hinterland uplift and climate. In order to understand the distribution of terrestrially sourced and marine palynomorphs in this depositional system comprising stacked turbidite flows, statistical analyses of palynology data from 41 wells have been conducted. These statistical studies support the division of the microplankton into nine groups, clustering taxa depending on their ecology and taphonomy. It is observed that the palynological assemblages are influenced by sediment provenance across the turbidite fans, the landmass vegetation ecology, and the marine microplankton populations varying across the basin. The dominant derived cluster groups B (peridinioids dominated by Apectodinium species) and E (probably autotrophic gonyaulacoids) comprise about 70% of the taxa recorded. These dinoflagellates bloomed as a result of low salinity surface waters and an increase in water-mass eutrophication resulting from the greenhouse climate optimal conditions of the PETM. The pollen and spore data, although challenging to interpret due to the varied quality of the data set, supports the interplay of a coastal wetland vegetation on extensive marginal delta systems, with associated wetland and swamp environments.