Architecture of the evaporite accumulation and salt structures dynamics in Tiddlybanken Basin, southeastern Norwegian Barents Sea

Abstract

An extensive, reprocessed two‐dimensional (2D) seismic data set was utilized together with available well data to study the Tiddlybanken Basin in the southeastern Norwegian Barents Sea, which is revealed to be an excellent example of base salt rift structures, evaporite accumulations and evolution of salt structures. Late Devonian–early Carboniferous NE‐SW regional extensional stress affected the study area and gave rise to three half‐grabens that are separated by a NW‐SE to NNW‐SSE trending horst and an affiliated interference transfer zone. The arcuate nature of the horst is believed to be the effect of pre‐existing Timanian basement grain, whereas the interference zone formed due to the combined effect of a Timanian (basement) lineament and the geometrical arrangement of the opposing master faults. The interference transfer zone acted as a physical barrier, controlling the facies distribution and sedimentary thickness of three‐layered evaporitic sequences (LES). During the late Triassic, the northwestern part of a salt wall was developed due to passive diapirism and its evolution was influenced by halite lithology between the three‐LES. The central and southeastern parts of the salt wall did not progress beyond the pedestal stage due to lack of halite in the deepest evaporitic sequence. During the Triassic–Jurassic transition, far‐field stresses from the Novaya Zemlya fold‐and‐thrust belt reactivated the pre‐salt Carboniferous rift structures. The reactivation led to the development of the Signalhorn Dome, rejuvenated the northwestern part of the salt wall and affected the sedimentation rates in the southeastern broad basin. The salt wall together with the Signalhorn Dome and the Carboniferous pre‐salt structures were again reactivated during post‐Early Cretaceous, in response to regional compressional stresses. During this main tectonic inversion phase, the northwestern and southeastern parts of the salt wall were rejuvenated; however, salt reactivation was minimized towards the interference transfer zone beneath the centre of the salt wall.

Effects of basement structures and Carboniferous basin configuration on evaporite distribution and the development of salt structures in Nordkapp Basin, Barents Sea—Part I

“…Finnmark Platform, the prominent Timanian structure (T5 anomaly) creates a platform between the NW-SE oriented graben G4 related to Tiddlybanken Basin and the CNB segment (Figure 11; Hassaan et al, 2020). Recently, Hassaan et al (2021) suggested a basement-involved, arcuate horst related to the pre-existing Timanian basement grain that could be the prolongation of the deep structure represented by the T5 magnetic anomaly and corresponding lineation towards the southeast (Figure 11b).…”

“…The region was under warm, arid to semi-arid climate conditions due to the drift into the subtropical zone, and as a consequence, the deposition of the warm-water carbonates and sabkha evaporites of the Gipsdalen Group (Figure 3) took place (Larssen et al, 2002;Stemmerik, 2000). The effect of the younger extension was less pronounced in the southeastern Norwegian Barents Sea, and layered evaporites within the Gipsdalen Group strata (Figure 3) were accumulated in postrift conditions (Figure 12b; Hassaan et al, 2020Hassaan et al, , 2021Rowan & Lindsø, 2017). The NW-SE oriented extensional stress regime (Figure 12b) affected the regional NW-SE trending half-grabens within the proto-Nordkapp Basin (Figure 12a).…”

“…Recently, Hassaan et al (2021) and Rowan and Lindsø (2017) demonstrated the impact of the presalt rift architecture on the accumulation of the LES, the subsequent passive diapirism and the rejuvenation of salt structures in the Tiddlybanken Basin (Figure 1a). This basin is situated to the southeast of the Nordkapp Basin but has its basin-axis oriented transverse to the Nordkapp Basin and is also much smaller in size.…”

“…Several studies suggested that in the Nordkapp Basin, salt diapirism was triggered by early Triassic thick-skinned extension (Jensen & Sørensen, 1992;Koyi et al, 1993Koyi et al, , 1995Nilsen et al, 1995;Rojo et al, 2019;Rojo & Escalona, 2018) and by loading of northwest Triassic progradation of sediments sourced from the Uralides (Dengo & Røssland, 1992;Grimstad, 2016;Rojo et al, 2019;Rowan & Lindsø, 2017). During the Triassic-Jurassic transition, the structural elements in the Barents Sea were slightly reactivated probably due to westward propagating compressional stress from the evolving Novaya Zemlya fold-and-thrust belt (Hassaan et al, 2020(Hassaan et al, , 2021Indrevaer et al, 2018;Müller et al, 2019). Minor subsequent reactivation has been suggested for the middle Jurassic and earliest Cretaceous (Hassaan et al, 2020).…”

Impact of Timanian thrust systems on the late Neoproterozoic–Phanerozoic tectonic evolution of the Barents Sea and Svalbard

“…Discrete Timanian structures with characteristic WNW-ESE strikes are sub-orthogonal to the N-S-trending Caledonian grain formed during the closure of the Iapetus Ocean (Gee et al, 1994;Witt-Nilsson et al, 1998;Johansson et al, 2004;. Thus far, Timanian structures have only been identified in onshore-nearshore areas of northwestern Russia and northeastern Norway and offshore in the Russian Barents Sea and southeasternmost Norwegian Barents Sea (Barrère et al, 2009(Barrère et al, , 2011Marello et al, 2010;Gernigon et al, 2018;Hassaan et al, 2020aHassaan et al, , 2020b. Therefore, the nature of basement rocks in the northern and southwestern Norwegian Barents Sea remains debatable.…”