The influence of pre-existing structure on the growth of syn-sedimentary normal faults in a deltaic setting, Niger Delta

Khani, Hamed Fazli; Back, Stefan

doi:10.1016/j.jsg.2015.01.011

Cited by 11 publications

(8 citation statements)

References 48 publications

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“…Many authors have concluded that preexisting structures exert a regional‐scale control on the location and geometry of rift basin, notably with respect to first‐order segmentation pattern. However, at the scale of individual faults and subbasins the relationship between prerift and rift structures may be less clear [ Whipp et al ., ; Fazli Khani and Back , ; Phillips et al , ].…”

Section: Introductionmentioning

confidence: 99%

Basement structure and its influence on the structural configuration of the northern North Sea rift

et al. 2017

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The northern North Sea rift basin developed on a heterogeneous crust comprising structures inherited from the Caledonian orogeny and Devonian postorogenic extension. Integrating two‐dimensional regional seismic reflection data and information from basement wells, we investigate the prerift structural configuration in the northern North Sea rift. Three seismic facies have been defined below the base rift surface: (1) relatively low‐amplitude and low‐frequency reflections, interpreted as pre‐Caledonian metasediments, Caledonian nappes, and/or Devonian clastic sediments; (2) packages of high‐amplitude dipping reflections (>500 ms thick), interpreted as basement shear zones; and (3) medium‐amplitude and high‐frequency reflections interpreted as less sheared crystalline basement of Proterozoic and Paleozoic (Caledonian) origin. Some zones of Seismic Facies 2 can be linked to onshore Devonian shear zones, whereas others are restricted to the offshore rift area. Interpreted offshore shear zones dip S, ESE, and WNW in contrast to W to NW dipping shear zones onshore West Norway. Our results indicate that Devonian strain and ductile deformation was distributed throughout the Caledonian orogenic belt from central South Norway to the Shetland Platform. Most of the Devonian basins related to this extension are, however, removed by erosion during subsequent exhumation. Basement shear zones reactivated during the rifting and locally control the location and geometry of rift depocenters, e.g., in the Stord and East Shetland basins. Prerift structures with present‐day dips >15° were reactivated, although some of the basement shear zones are displaced by rift faults regardless of their orientation relative to rift extension direction.

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Section: Introductionmentioning

confidence: 99%

Basement structure and its influence on the structural configuration of the northern North Sea rift

et al. 2017

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“…Van Rensbergen and Morley, 2000), the presence of pre-existing shale structures (e.g. Sapin et al, 2012;Fazlikhani and Back, 2015), temporal and spatial variations in sediment accummulations rates (e.g. Chima et al, 2022), the existence of fluid expulsion structures (Back and Morley, 2016), the occurrence of a base-shale relief (Chima et al, 2022), the deep flow of mobile shale under either brittle or ductile conditions (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Fazlikhani and Back, 2012). Most of studies listed above provide only twodimensional treatments of shale tectonics and only very few have inspected their threedimensional evolution (Fazlikhani andBack., 2012, 2015;Ahmed et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

Extensional Deformation of a Shale-dominated Delta: Tarakan Basin, Offshore Indonesia

Erdi¹,

Jackson²,

Soto³

2023

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Deformation on shale-rich continental margins is commonly associated with thin-skinned extension above mobile shales. Normal faulting and shale mobilization are widespread on such margins, being associated with and controlled by progradation and gravitational failure of deltaic sedimentary wedges. However, due to limitations in our ability to seismically imaging these mobile shales, our understanding of how base-shale relief controls deformation, and the shape, size, and distribution of shale structures remain poorly understood. We here use 3D seismic reflection data from the Tarakan Basin, offshore Indonesia to investigate the temporal and spatial evolution of thin-skinned deformations of the Neogene sedimentary section. Our detailed seismic interpretation reveals long (≤ 74 km), concave- and convex-into-the-basin faults, dipping both basinward (eastwards) and locally landward (westwards), which detach downwards on a basal mobile shale (Middle Miocene). The base of the shale unit dips gently (< 17o) seaward, although older (Paleogene), rift-related normal faults mean a local base-shale relief is present. Our analysis of isochron (thickness map) analysis shows that supra-shale normal faulting commenced in the Middle Miocene and was accompanied by the formation of hanging wall rollover folds and associated crestal grabens, with the subsequent along- and across strike migration of strain being related to the nucleation, lateral linkage, and reactivation of individual fault systems. Updip growth faulting was also accompanied by the downslope flow of mobile shale, margin-parallel and-perpendicular differential loading, and local contraction and mobile shale-upbuilding, resulting in the growth of large, margin-parallel shale anticlines further downdip. These faults and anticlines are locally overlain by tall (≤ 5 km) mud diapirs and volcanoes. We suggest that variations in the rate of sediment loading, mobile shale flow, fault growth, and gravitational failure above a seaward-dipping, but slightly rugose base-shale surface, controlled Neogene deformations in the Tarakan Basin. We also demonstrate how variations in the trend and dip of the base-shale surface influences the position, timing, and evolution of supra-shale faults and their associated depocenters along shale-rich, delta-fed clastic margins.

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“…Such presumably weak heterogeneities include discrete faults (with limited width), diffuse shear zones (up to several 10s of km-wide) and mobile belts (up to 100s of km-wide), and orogenic structural templates, all of which create crustal-scale rheological and mechanical anisotropies (e.g., Daly et al, 1989;Ranalli & Yin, 1990). Numerous subsurface-and fieldbased studies suggest such pre-existing structures can influence the location, orientation, dimensions, segmentation, and interaction of subsequent rift-related structures (e.g., Daly et al, 1989;Bartholomew et al, 1993;Maurin & Guiraud, 1993;Maerten et al, 2002;Morley et al, 2004;Morley, 2010;Kirkpatrick et al, 2013;Fazlikhani & Back, 2015;Salomon et al, 2015;de Castro et al, 2016;Phillips et al, 2016;Fazlikhani et al, 2017;Dawson et al, 2018;Kolawole et al, 2018;Muirhead & Kattenhorn, 2018;Rotevatn et al, 2018;Collanega et al, 2019;Heilman et al, 2019;Osagiede et al, 2020a).…”

Section: Introductionmentioning

confidence: 99%

Influence of zones of pre-existing crustal weakness on strain localization and partitioning during rifting: Insights from analogue modeling using high resolution 3D digital image correlation

Osagiede¹,

Rosenau²,

Rotevatn³

et al. 2022

Preprint

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The factors controlling the selective reactivation of pre-existing crustal structures and strain localization process in natural rifts have been studied for decades but remain poorly understood. We present the results of surface strain analysis of a series of analogue rifting experiments designed to test the influence of the size, orientation, depth, and geometry of pre-existing crustal weak zones on strain localization and partitioning. We apply distributed basal extension to crustal-scale models that consist of a silicone weak zone embedded in a quartz sand layer. We vary the size and orientation (θ-angle) of the weak zone with respect to the extension direction, reduce the thickness of the sand layer to simulate a shallow weak zone, and vary the geometry of the weak zone to reflect a range of anticlinal, either linear or curvilinear natural weak zone geometries. Our results show that at higher θ-angle (≤ 60o) both small- and large-scale weak zones localize strain into graben-bounding (oblique-) normal faults. At lower θ-angle (≤ 45o), small-scale weak zones do not localize strain effectively, unless they are shallow. We observe diffuse, second-order strike-slip internal graben structures, which are conjugate and antithetic under orthogonal and oblique extension, respectively. In general, the changing nature of the rift faults (from discrete fault planes to diffuse fault zones, from normal to oblique and strike-slip) highlights the sensitivity of rift architecture to the orientation, size, depth, and geometry of pre-existing weak zones. Our generic models are comparable to observations from many natural rift systems like the northern North Sea and East Africa, and thus have implications for understanding the role of structural inheritance in rift basins globally.

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The influence of pre-existing structure on the growth of syn-sedimentary normal faults in a deltaic setting, Niger Delta

Cited by 11 publications

References 48 publications

Basement structure and its influence on the structural configuration of the northern North Sea rift

Basement structure and its influence on the structural configuration of the northern North Sea rift

Extensional Deformation of a Shale-dominated Delta: Tarakan Basin, Offshore Indonesia

Influence of zones of pre-existing crustal weakness on strain localization and partitioning during rifting: Insights from analogue modeling using high resolution 3D digital image correlation

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