Structural and depositional controls on the distribution of the Upper Jurassic shallow marine sandstones in the Fife and Angus fields area, Quadrants31 & 39, UK Central North Sea

An integrated evaluation of the tectonic and depositional history of the Up per Jurassic of the Fife and Angus area of UK Quadrants 31 and 39 has been carried out through 3D seismic interpretation and a range of geological stu dies. Sedimentological and petrological data indicate that the Upper Jurass ic sands in the study area are the lateral equivalents of the Fulmar Format ion. They can be divided into three groups of sandstones, deposited by diff erent processes during an interval of almost 10 million years: (i) open she lf, Group 1 sandstones comprise sands dominated by storm/wave activity, whi ch accumulated in fault-bounded mini-basins ('embayments'); (ii) Group 2 sa ndstones, possibly deposited by storm-induced flows; and (iii) Group 3 sand stones, which may represent subaqueous dunes deposited in a tidally-influen ced, shallow marine environment. Sedimentological and heavy mineral studies suggest that the sands in the st udy area were sourced from the adjacent Mid North Sea High and were transpo rted along the shelf probably by wave, storm and tide-generated currents. B iostratigraphic dating indicates that the Upper Jurassic sands in the Fife/ Angus area were deposited during Late Kimmeridgian to upper Middle Volgian. An earlier depositional period with a possible Callovian age is also infer red. Deposition of Jurassic sediments in the study area occurred during two transgression periods (Callovian and upper Late Jurassic), separated by an erosional/non-depositional phase (Oxfordian to Middle Kimmeridgian). The a ccumulation of Late Jurassic sands started in the Fife embayment and progre ssed northwards. It was confined, however, to the eastern side of the embay ments, possibly due to the hydrodynamic conditions of the area. (C) 2000 El sevier Science Ltd. All rights reserved.