Sedimentology of the heterolithic and tide-dominated tilje formation (Early Jurassic, Halten Terrace, Offshore Mid-Norway)

摘要: The Early Jurassic Tilje Formation on the Halten Terrace, offshore mid-Norway, was deposited in a relatively narrow but long seaway connecting Boreal Ocean north and Tethys south. Sediments of Smorbukk Heidrun Fields have been classified into ten facies associations. Many lithofacies are mud-rich typified by strong grain-size contrasts. In addition, all two associations tidally influenced or dominated. As result, 80% total rock volume consists very heterolithic sediments characterised rapidly alternating changes between mudstone siltstone fine-to medium-grained sandstone. Formation, recognition interpretation is crucial to understanding depositional conditions stratigraphic architecture. classification scheme associated breakdown cored wells served define successive conceptual models that placed sequence framework. lower part (T1 most T2) envisaged formed response base-level fall, creating series low-relief valleys, subsequent rise resulting formation tide- wave-dominated estuarine system. upper (top T2 T6) interpreted as fluvial-dominated delta-like These contrasting styles resulted different three-dimensional architectures, relative proportions, stacking patterns, which implications for reservoir model-building methods.