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High-Resolution Seismic Imaging and Modeling of Structural and Stratigraphical Features in the Southwest Barents Sea

Abstract

High-resolution P-Cable and conventional 3D seismic data have been used to image and map shallow structural

and stratigraphic features in the Hoop area, SW Barents Sea. The gap in resolution between the P-Cable and

conventional seismic data has been addressed by synthetic seismic modelling, partly motivated by outcrop

information. The seismic modelling shed light on the resolution allowed by seismic data; combined with detailed

observations in the P-Cable data, improved confidence in the interpretation of the conventional seismic data can

be achieved. Synthetic seismic data based on conceptual fault geometries inspired by field observations are

compared to real seismic data. A wide range of frequencies are tested in the seismic modelling to demonstrate

the differences in resolution, which thus determine minimum scales for identifiable sedimentary features and

faults in the subsurface. The P-Cable data typically have resolution of 4-7 m in the shallow subsurface, up to four

times better than in conventional data. The high-resolution P-Cable seismic data thus reveal complex

stratigraphic and structural features, such as small-scale clinoforms and smaller faults. The Lower Cretaceous

delta succession belongs to a large delta and shelf system that prograded from NW into the study area during the

Barremian. The seismic data image characteristic clinoforms at various scales making it possible to map

architecture and thus constrain depositional environments in some cases. The large-scale clinoforms typically

have heights of 150-200 m and dips of 0.65-1.13° after correcting for compaction related to 2150 m deeper

maximum burial before Cenozoic uplift and erosion. The Lower Cretaceous delta and shelf succession from NW

in the study area is faulted, and thus the main Early Cretaceous fault activity post-dates the Barremian arrival of

the delta. Detailed ties to wells with biostratigraphic age data, reveal an Aptian?-early Albian age of the main

faulting event. Faulting likely initiated in the Aptian but a hiatus/condensed section makes it difficult to constrain

the exact onset of offset. Combining the new constraints on the faulting in the Hoop area with similar structures

observed in the neighbouring Fingerdjupet Subbasin document a significant Early Cretaceous extensional event

causing subsidence in a broad NNE trending basin province and a transgressional system reaching Svalbard in

Albian time.