Sedimentary Evolution of the Bashkirian- Moscovian Siliciclastic-carbonate Deposits of the Loppa High (Barents Sea)

摘要

The studied Bashkirian-Moscovian cored section was recovered from a buried isolated structural feature named Loppa High (Norwegian Barents Sea). The section (283 m thick) is characterized by continental to shallow-marine siliciclastics, stepwise replaced upwards by subtidal carbonates of the Gipsdalen Group, considered as major reservoir-prone Unit of the Upper Paleozoic sediments of the Barents Sea. This study has been focused as first step, on the identification of the main lithostratigraphic and sedimentological features. Specific lithofacies associations have been then identified, in order to define depositional facies models to better explain the particular evolution of this sedimentary system controlled by both tectonic and eustatism. Metric to decametric shallowing- and deepening- upward trends have been individuated, superimposed on a 3rd order Bashkirian to Early Moscovian transgressive depositional trend, also recognizable in other areas of the western Barents Sea. The post-depositional history of the section reveals a strong diagenetical overprint mainly affecting the carbonates deposits through dolomitization and silicification processes. The analysis of measured porosity and permeability trends of the carbonates across the section allowed to develop preliminary conclusions about a potential strong control of the diagenesis on the reservoir potential of these rocks.