Sedimentology and Stratigraphic Architecture of Fluvial to Shallow Marine Deposits

The interaction of fluvial, tidal and wave processes in coastal and paralic environments gives rise to accumulations represented in the sedimentary record by varied types of architectural elements. The internal facies characteristics and external preserved geometry of these sedimentary units is determined by the morphology and the evolutionary behaviour of the range of coastal sub-environments. This study includes the results of two related projects. The first project analyses fluvial to shallow marine deposits through the consideration of subsurface dataset obtained from the Middle Jurassic lower Dhruma Formation in Saudi Arabia. The dataset comprises facies descriptions based on cores, thin sections, gamma-ray loges and FMI images. It achieves the following: i) it examines and demonstrates sedimentary relationships between various fluvial, nearshore and shallow-marine deposits; ii) it develops depositional models to account for the stratigraphic complexity inherent in fluvial to shallow-marine successions; iii) it documents the sedimentology and the stratigraphic evolutionary patterns of the lower Dhruma Formation in the studied area of Saudi Arabia. The second project examines estuarine tidal bars based on quantitative data extracted from many published studies. The second project i) investigates the geometry and size of tidal bars known from modern systems and their deposits preserved in ancient outcropping successions; ii) illustrates their sedimentological characters (internal facies organisation, external form and architectural geometry); iii) investigates the nature of juxtaposition of tidal bars in association with other estuarine and shallow-marine elements; iv) highlights tidal-bar development and preservation; and vi) presents implications of the results for reservoir prediction and characterisation