Environments of Sedimentation and Distribution of the Jurassic Strata

摘要

The Jurassic period characterised by the transgression of the Arctic Ocean with its maximum transgression in the Tithonian, when the organic reach black shales were deposited. During the Early and Middle Jurassic the change occurred from an arid to a humid climatic regime, resulting in increased run-off and the transport of sediments out onto the shelf. The most uplifted areas at Jurassic period were the Svalbard Archipelago, the Central Zone of the Barents steps, Baltic shield, Finnmark platform, Frants Joseph Land, The Novaya Zemlay archipelago and Timan-Pechora anticline. These areas could be the main sources of material. Many of the most important oil and gas reservoirs of the Barents sea basin were deposited during the Early and Middle Jurassic. Eastern and Western part of Barents have been developed simultaneously within the one basin. Thereby that allowed us to mark out five transgressive-regressive regional cycles. A gradual thinning of sequences from east towards west indicates a general increase in accommodation space during deposition towards east. The Jurassic sandstones are one of the main reservoirs on the Barents Sea shelf and have rather good reservoir properties.