Mobile evaporite controls on the structural style and evolution of rift basins: Danish Central Graben, North Sea

Duffy, Oliver B.; Gawthorpe, Rob L.; Docherty, Matthew; Brocklehurst, Simon H.

doi:10.1111/bre.12000

Cited by 51 publications

(82 citation statements)

References 53 publications

(117 reference statements)

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“…In the Silver Pit Basin, salt‐cored anticlines in the basin centre developed contemporaneously with reactive diapirs and salt rollers at the basin edges, that is, along the Dowsing fault zone and the North Dogger fault zone (Figure c; Allen et al., ; Coward & Stewart, ; Griffiths et al., ; Stewart, Harvey, Otto, & Weston, ; Stewart, ). Indications for sub‐salt faulting and reactive diapirism can be found in the northern Central Graben and the adjacent Step Graben (Arfai et al., ; Duffy et al., ; Rank‐Friend & Elders, ; Van Winden, ) as well as in the Broad Fourteens Basin (Duin, Doornenbal, Rijkers, Verbeek, & Wong, ; Wong, Batjes, de Jager, & van Wetenschappen, ), the Terschelling Basin (Harding & Huuse, ) and the Lauwerszee Trough (Strozyk et al., ).…”

Section: Resultsmentioning

confidence: 99%

The timing of salt structure growth in the Southern Permian Basin (Central Europe) and implications for basin dynamics

et al. 2018

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In this paper, a literature‐based compilation of the timing and history of salt tectonics in the Southern Permian Basin (Central Europe) is presented. The tectono‐stratigraphic evolution of the Southern Permian Basin is influenced by salt movement and the structural development of various types of salt structures. The compilation presented here was used to characterize the following syndepositional growth stages of the salt structures: (a) “phase of initiation”; (b) phase of fastest growth (“main activity”); and (c) phase of burial’. We have also mapped the spatial pattern of potential mechanisms that triggered the initiation of salt structures over the area studied and summarized them for distinct regions (sub‐basins, platforms, etc.). The data base compiled and the set of maps produced from it provide a detailed overview of the spatial and temporal distribution of salt tectonic activity enabling the correlation of tectonic phases between specific regions of the entire Southern Permian Basin. Accordingly, salt movements were initiated in deeply subsided graben structures and fault zones during the Early and Middle Triassic. In these areas, salt structures reached their phase of main activity already during the Late Triassic or the Jurassic and were mostly buried during the Early Cretaceous. Salt structures in less subsided sub‐basins and platform regions of the Southern Permian Basin mostly started to grow during the Late Triassic. The subsequent phase of main activity of these salt structures took place from the Late Cretaceous to the Cenozoic. The analysis of the trigger mechanisms revealed that most salt structures were initiated by large‐offset normal faults in the sub‐salt basement in the large graben structures and minor normal faulting associated with thin‐skinned extension in the less subsided basin parts.

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Section: Resultsmentioning

confidence: 99%

The timing of salt structure growth in the Southern Permian Basin (Central Europe) and implications for basin dynamics

et al. 2018

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“…This is caused by preferential flow within the salt driven by the basinward dip of the model immediately prior to overburden translation. The monocline and cover outer‐arc extension are also typical geometries associated with end of rift stretching and syn‐depositional salt flow (Duffy et al, ; Jackson & Hudec, ; Rowan, ). For simplicity and general applicability, we do not simulate syn‐kinematic sedimentation and assume a homogeneous overburden underlain by a salt interval with densities of, respectively, 2.3 g cm −3 and 2.16 g cm −3 .…”

Section: Methods and Models Designmentioning

confidence: 99%

The Impact of Pre‐Salt Rift Topography on Salt Tectonics: A Discrete‐Element Modeling Approach

Pichel

Finch²,

Gawthorpe

2019

Tectonics

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Gravity‐driven salt tectonics along passive margins is commonly depicted as comprising domains of updip extension and downdip contraction linked by an intermediate, broadly undeformed zone of translation. This study expands on recently published physical models using discrete‐element modeling to demonstrate how salt‐related translation over pre‐salt rift structures produce complex deformation and distribution of structural styles in translational salt provinces. Rift geometries defined by horsts and tilted fault‐blocks generate base‐salt relief affecting salt flow, diapirism and overburden deformation. Models show how flow across pairs of tilted fault‐blocks and variably‐dipping base‐salt ramps associated with pre‐salt faults and footwalls produce abrupt flux variations that result in alternation of contractional and extensional domains. Translation over tilted fault‐blocks defined by basinward‐dipping normal faults results in wide, low amplitude inflation zones above footwalls and abrupt subsidence over steep fault‐scarps, with reactive diapirs that are squeezed and extrude salt as they move over the fault. Translation over tilted‐blocks defined by landward‐dipping faults produces narrow inflation zones over steep fault‐scarps and overall greater contraction and less diapirism. As salt and cover move downdip, structures translate over different structural domains, being inverted and/or growing asymmetrically. Our models allow, for the first time, a detailed evolution of these systems in cross‐section and demonstrate the effects of variable pre‐salt relief, salt sub‐basin connectivity, width and slope of base‐salt ramps. Results are applicable to syn‐ and post‐rift salt basins; ultimately improving understanding of the effects of base‐salt relief on salt tectonics and working as a guide for interpretation of complex salt deformation.

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“…halite, potash salt). Salt basin morphology is thus a key control on lithology distribution in salt giants and the resulting spatial variations in the mechanical‐stratigraphic of the prerift template may directly govern structural styles during subsequent phases of crustal extension (Clark et al, ; Duffy et al, ; Ge et al, ; Jackson & Lewis, ; Lewis et al, ; Marsh et al, ; Stewart et al, ; Wilson et al, ).…”

Section: Interpretation and Discussionmentioning

confidence: 99%

Salt thickness and composition influence rift structural style, northern North Sea, offshore Norway

et al. 2019

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“Salt” giants are typically halite‐dominated, although they invariably contain other evaporite (e.g. anhydrite, bittern salts) and non‐evaporite (e.g. carbonate, clastic) rocks. Rheological differences between these rocks mean they impact or respond to rift‐related, upper crustal deformation in different ways. Our understanding of basin‐scale lithology variations in ancient salt giants, what controls this and how this impacts later rift‐related deformation, is poor, principally due to a lack of subsurface datasets of sufficiently regional extent. Here we use 2D seismic reflection and borehole data from offshore Norway to map compositional variations within the Zechstein Supergroup (ZSG) (Lopingian), relating this to the structural styles developed during Middle Jurassic‐to‐Early Cretaceous rifting. Based on the proportion of halite, we identify and map four intrasalt depositional zones (sensu Clark et al., Journal of the Geological Society, 1998, 155, 663) offshore Norway. We show that, at the basin margins, the ZSG is carbonate‐dominated, whereas towards the basin centre, it becomes increasingly halite‐dominated, a trend observed in the UK sector of the North Sea Basin and in other ancient salt giants. However, we also document abrupt, large magnitude compositional and thickness variations adjacent to large, intra‐basin normal faults; for example, thin, carbonate‐dominated successions occur on fault‐bounded footwall highs, whereas thick, halite‐dominated successions occur only a few kilometres away in adjacent depocentres. It is presently unclear if this variability reflects variations in syn‐depositional relief related to flooding of an underfilled presalt (Early Permian) rift or syn‐depositional (Lopingian) rift‐related faulting. Irrespective of the underlying controls, variations in salt composition and thickness influenced the Middle Jurassic‐to‐Early Cretaceous rift structural style, with diapirism characterising hangingwall basins where autochthonous salt was thick and halite‐rich and salt‐detached normal faulting occurring on the basin margins and on intra‐basin structural highs where the salt was too thin and/or halite‐poor to undergo diapirism. This variability is currently not captured by existing tectono‐stratigraphic models largely based on observations from salt‐free rifts and, we argue, mapping of suprasalt structural styles may provide insights into salt composition and thickness in areas where boreholes are lacking or seismic imaging is poor.

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Mobile evaporite controls on the structural style and evolution of rift basins: Danish Central Graben, North Sea

Cited by 51 publications

References 53 publications

The timing of salt structure growth in the Southern Permian Basin (Central Europe) and implications for basin dynamics

The timing of salt structure growth in the Southern Permian Basin (Central Europe) and implications for basin dynamics

The Impact of Pre‐Salt Rift Topography on Salt Tectonics: A Discrete‐Element Modeling Approach

Salt thickness and composition influence rift structural style, northern North Sea, offshore Norway

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