Biostratigraphic data for reservoir correlation and the prediction of basin-fill evolution in sand-rich turbidite successions
In deep-water clastic successions biostratigraphy is routinely used to provide a framework for correlation through biozonation schemes and to infer general depositional setting. There is, however, an absence of rigorous, quantitative, data to support palaeoenvironmental interpretations at the detailed scale of recognizing the different architectural elements of deep-water depositional systems, especially those that have similar sedimentological and wireline log signatures when seen in isolated vertical subsurface sections. This study therefore investigates the foraminiferal micropalaeontology of the Kirkgecit Formation of the Elazig Basin of eastern Turkey in order to test the applicability of biostratigraphy to detailed palaeoenvironmental determination. The project endeavours to test spatial variability in biofacies and evaluate this in terms of determining subsurface geometry. An underlying theme of the investigation is to relate palaeontological to sedimentological data and to develop novel interpretations and prediction of the elements in the evolution of deep-water clastic systems. The study has focused on the quantitative foraminiferal assemblages (biofacies) of fine-grained sediment associated with the sedimentologically-defined sand-rich turbidite architectural elements. It has been possible to interpret and define 15 architectural elements in terms of their inherent foraminiferal biofacies. Additionally it has been possible to subdivide sedimentologically very similar architectural elements into new elements of finer resolution. Broader biofacies variation has been linked to variations in palaeobathymetry. In terms of biofacies, attention has focused on the morphogroups represented by the formaminifera, rather than classical taxonomy. This has avoided the uncertainties inherent in classical taxonomy such as variation with species concepts and synonymy. Instead attention has focused on morphological variation associated with differing environmental parameters, especially water energy/motion substrate and oxygenation. Eleven morphogroups have been defined, each further divisible into four subgroups based on ornament.