The western Koryak fold and thrust belt consists of a set of tectonostratigraphic terranes that contain units ranging from Lower Palaeozoic to Cenozoic. Three deformational events have been identified in the study area. The first event structures are folds, domes and shear zones with related high-pressure/ low-temperature metamorphism. These structures are early Carboniferous and are only recognized in the metamorphic terranes. The second event structures are imbricate fans of thrusts and folds with southeast vergence, broken formation and serpentinite mélange. These are latest Jurassic to early Cretaceous (early Albian) and occur throughout the study area. During this event, thrusting was accompanied by dextral strike-slip faulting. The second event structures are overlapped by the Upper Albian sedimentary rocks with an angular unconformity at the base. During metamorphism associated with the first and second deformational events, some of the rocks were metamorphosed to blueschist grade and were affected by strain with axial ratios of up to 15:1. The third deformational event is characterized by significant sinistral strike-slip displacement at higher crustal levels. This resulted in a new set of structures and rotation of pre-existing structures. The age of the sinistral strike-slip faults is interpreted to be late Cretaceous to Cenozoic. The kinematics of the second and third deformational events correspond to assumed proto-Pacific plate motions based on palaeomagnetic data.
Abstract. Strikingly similar Late Mesoproterozoic stratigraphic sequences and correlative U-Pb detrital-zircon ages may indicate that the Sette Daban region of southeastern Siberia and the Death Valley region of southwestern North America were formerly contiguous parts of a Grenville foreland basin. The Siberian section contains large numbers of detrital zircons that correlate with Grenville, GraniteRhyolite, and Yavapai basement provinces of North America. The sections in both Siberia and Death Valley exhibit west-directed thrust faults that may represent remnants of a Grenville foreland thrust belt. North American detritalzircon components do not occur in Siberian samples above a ∼600 Ma breakup unconformity, suggesting that rifting and continental separation blocked transfer of clastic sediment between the cratons by 600 Ma. Faunal similarities suggest, however, that the two cratons remained within the breeding ranges of Early Cambrian trilobites and archeocyathans.
The Barents Sea sedimentary basin represents one of the key prospective regions for hydrocarbon resources in the Arctic realm (Figures 1a and 1b). However, while the Norwegian part of the Barents Sea is covered by a dense network of seismic lines and penetrated by numerous wells, the Russian portion is comparatively poorly studied. To date, the sedimentary succession of the Russian part has only been penetrated by a few wells drilled in the southern part of the basin and four wells drilled onshore across the Franz Josef Land (FJL) archipelago. FJL represents an important region, where the Mesozoic succession is exposed onshore for geological study (Figure 2b). Due to the lack of offshore wells, this archipelago represents the only area in the north-eastern Barents Sea where the Mesozoic succession can be directly described and sampled, offering vital insights into the geological evolution of this insufficient studied region.The deeper pre-Mesozoic succession of the north-eastern Barents Sea has been mainly constrained by seismic data (
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