--> --> Tectonic Evolution, Structural Styles and Plays of the Russian Chukchi Sea Sedimentary Basins

2018 AAPG International Conference and Exhibition

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Tectonic Evolution, Structural Styles and Plays of the Russian Chukchi Sea Sedimentary Basins

Abstract

Sedimentary basins of the Russian Chukchi Sea are believed to possess a significant hydrocarbon potential. At present they are still underexplored and require further in-depth geological studies. This work aimed at unravelling tectonic evolution of the basins with a pragmatic objective to analyze structural styles and associated plays. Various structures were mapped and attributed to compressional and extensional styles using 2D seismic and gravmag data. The region in question covers the South Chukchi (Hope in US) Basin and the North Chukchi Basin as well as adjacent offshore areas within the Chukchi and Arctic Platforms. These basins and their fills have evolved under multiple stages of extensional and compressional tectonics, some featuring a considerable strike-slip component and some with possible local salt presence and movement. Progression of tectonic settings produced a diverse range of positive structures in the sedimentary cover ranked by frequency of their appearance into six main types: a) extensional rollover anticlines, b) basement-drape anticlines, c) positive flower structures, d) inversion structures, e) compressional anticlines in front of the fold and thrust belt and f) salt-related structures. Timing of deformations was also reviewed by observing associated unconformities and syn-kinematic growth strata resulting in principal ages of structuration. Our interpretation is reasonably supported by published data on age of exhumation, age and attitude of dykes as a proxy of extensions, kinematics and morphology of faults, preferential strike of folds suggesting principal vectors of compression and extension studied in adjacent regions. Contiguous structural types can be combined into geographic domains providing certain similarities in exploration strategies. Each structural type described can make up a potential structural and/or structural-stratigraphic play within established play fairways. Certain aspects of play risking can be performed on the basis of timing of structuration, extent of compartmentalization, volumes etc. from interpretation provided by this study.