Structural inheritance in amagmatic rift basins: Manifestations and mechanisms for how pre-existing structures influence rift-related faults

Samsu, Anindita; Micklethwaite, Steven; Williams, Jack N.; Fagereng, Åke; Cruden, Alexander R.

doi:10.1016/j.earscirev.2023.104568

Cited by 6 publications

(4 citation statements)

References 279 publications

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“…Many of previous studies support that there is a significant relationship between the reactivation of pre-existing fabrics and their obliquity relative to extension direction (Deng et al, 2017(Deng et al, , 2018Maestrelli et al, 2020;Molnar et al, 2019;Morley et al, 2004). When reactivated, inherited fabrics can cause curvature of faults and some typical fault patterns (such as S-shaped or J-shaped top-view geometries) giving rise to complicated rift-related deformation patterns (e.g., Bellahsen & Daniel, 2005;Bellahsen et al, 2006;Bladon et al, 2015;Bonini et al, 2023;Camanni & Ye, 2022;Corti et al, 2007Corti et al, , 2013Henza et al, 2010Henza et al, , 2011Hodge et al, 2018;Morley, 1999bMorley, , 2010Morley et al, 2004;Philippon et al, 2015;Phillips et al, 2016Maestrelli et al, 2020;Samsu et al, 2021Samsu et al, , 2023Wang et al, 2021;Wu et al, 2020;Ye et al, 2020;Zwaan et al, 2021aZwaan et al, , 2021b. A1 for detailed data.…”

Section: Discussionmentioning

confidence: 96%

Influence of Inherited Brittle Fabrics on Continental Rifting: Insights From Centrifuge Experimental Modeling and Application to the East African Rift System

Zou,

Maestrelli,

Corti

et al. 2023

Tectonics

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The presence of pre‐existing fabrics at all lithospheric scales has been proven to be of primary importance in controlling the evolution of continental rifts. Indeed, observations from natural examples show that even in conditions of orthogonal rifting, when extension should result in simple fault patterns dominated by normal faults orthogonal to extension vectors, inherited fabrics induce complex arrangements of differently‐oriented extension‐related structures. This paper explored the influence of inherited fabrics on rift‐related structures by using a series of analog models deformed in a centrifuge. The models reproduced a brittle‐ductile crustal system and considered the presence of pre‐existing discrete fabrics in the brittle crust in conditions of orthogonal narrow rifting. These fabrics were reproduced by cutting the brittle layer at different orientations with respect to the extension direction. Modeling shows pre‐existing fabrics have a significant influence on rift‐related faults, provided that the angle between inherited fabrics and the rift trend is less than 45°. In these conditions, fabrics cause prominent segmentation of rift‐related faults and induce the development of isolated depocenters. Pre‐existing fabrics strongly influence the geometry of extension‐related structures, resulting in curved fault patterns and en‐echelon arrangement of oblique faults. These findings provide insights into the development of continental rift systems in nature: our modeling shows indeed significant similarities (i.e., peculiar fault architecture and geometries) with the faults in different sectors of the East African Rift System (e.g., the Magadi and Bogoria basin, Kenya Rift), testifying that reactivation of inherited fabrics is a paramount process in shaping continental rifts.

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Section: Discussionmentioning

confidence: 96%

Influence of Inherited Brittle Fabrics on Continental Rifting: Insights From Centrifuge Experimental Modeling and Application to the East African Rift System

Zou,

Maestrelli,

Corti

et al. 2023

Tectonics

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“…A potential model is that shear zones localize viscous deformation in the mid‐ to lower crust, and thus have some control on the orientation of overlying faults (Dawson et al., 2018; Hodge et al., 2018; Kolawole et al., 2018; Wedmore et al., 2020); what Samsu et al. (2023) suggests referring to as “soft‐linked structural inheritance.” Next we will quantify the metamorphic pre‐conditioning of Malawi lower‐crustal rocks, which will allow a discussion on possible weakening mechanisms and their requirements.…”

Section: Regional Geology Tectonics and Thermal Structurementioning

confidence: 99%

“…Where studied in detail, faults in Malawi appear to follow foliations locally where reasonably well-but not optimally-oriented for reactivation, and cross-cut them elsewhere (Hodge et al, 2018;Wedmore et al, 2020;Williams et al, 2019). A potential model is that shear zones localize viscous deformation in the mid-to lower crust, and thus have some control on the orientation of overlying faults (Dawson et al, 2018;Hodge et al, 2018;Kolawole et al, 2018;Wedmore et al, 2020); what Samsu et al (2023) suggests referring to as "soft-linked structural inheritance." Next we will quantify the metamorphic preconditioning of Malawi lower-crustal rocks, which will allow a discussion on possible weakening mechanisms and their requirements.…”

Section: Conditions and Setting Of Lower-crustal Seismicitymentioning

confidence: 99%

Metamorphic Inheritance, Lower‐Crustal Earthquakes, and Continental Rifting

Fagereng,

Diener,

Tulley

et al. 2024

Geochem Geophys Geosyst

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The Malawi Rift is localized within Precambrian amphibolite‐granulite facies metamorphic belts, bounded by up to 150 km long border faults, and generates earthquakes throughout ∼40 km thick crust. Rift‐related faults are inferred to exploit pre‐existing weaknesses that allow rifting of otherwise dry and strong crust. It is unclear what these weaknesses are, and how localization into weak zones can be reconciled with strength required for lower crustal seismicity. We present results of mineral equilibria modeling, which indicate that Proterozoic metamorphism generated dry crust dominated by a quartz‐feldspar assemblage that is metastable at current conditions. For rift propagation to be possible at current cool thermal gradients and in mechanically strong, dry quartzofeldspathic rocks, mid‐ to lower‐crustal strain must be localized into relatively weak, inherited shear zones that deform primarily by aseismic, viscous creep. These shear zones are embedded within high‐strength crust, and interaction between creeping shear zones and enveloped or surrounding rocks may locally increase stress and trigger frictional, seismic slip at mid‐ to lower‐crustal depths. Over time, this interaction may produce a fracture network that allows infiltration of fluids. We therefore suggest that during rifting of previously deformed and metamorphosed crust, major faults are most likely to grow from below, with their location and orientation prescribed by underlying inherited viscous shear zones. In this case, fluids may infiltrate and locally weaken metastable lower crust, including allowing time‐dependent fluid‐driven seismicity and local partial melting, but length‐scales of this weakening is limited by the scale of the permeability network.

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“…Whilst this has long been recognized, over the last decade, the quality and resolution of seismic data, especially 3D seismic data, have been significantly improved, which has enabled identification of basement structures within both pre-rift strata and crystalline basement (Collanega et al, 2019;Guan et al, 2023;Osagiede et al, 2020;Phillips et al, 2016;Wu et al, 2020). The exact manner in which basement structures reactivate and the degree that basement structures exert their influence on rift geometry and fault evolution are now well documented (Bird et al, 2015;Cheng et al, 2023;Fazlikhani et al, 2017;Morley, 2014;Phillips et al, 2016Phillips & McCaffrey, 2019;Pichel et al, 2023;Samsu et al, 2023;Shaban et al, 2023;Strugale et al, 2021;Wang et al, 2022;Wu et al, 2020;Ye et al, 2020). However, few studies have considered how, or indeed if, variations in structural heterogeneity influence not only the presence but also the nature of rift segmentation through subsurface seismic data (Clemson et al, 1997;Zhong & Escalona, 2020).…”

Section: Introductionmentioning

confidence: 99%

Rift segmentation caused by reactivation of multiple basement structure systems: Evidence from the Hailar‐Tamtsag Rift, northeast Asia

Wu,

Shen,

Paton

et al. 2024

Basin Research

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Since the influence of structural inheritance on rift geometry has been widely documented, it is easy to assume that rift segmentation, a prominent feature of rift geometry, may have been also influenced by structural heterogeneity. However, limited studies using high‐quality seismic data have considered how basement reactivation is accommodated at individual fault scale and then how this results in rift segmentation at sub‐basin scale. Using extensive high‐quality 3D seismic data and 76 borehole data, we investigate the characteristics of rift architecture, rift‐related fault systems, basement structures and rift evolution in the Hailar‐Tamtsag Rift, northeast Asia. We identify three distinct rift segments which are defined by three rift‐related fault systems and accompanied by three underlying basement structure systems. We recognize three phases of basement reactivation and three types (including five styles) of interactions between basement structures and rift‐related faults. Our study shows that rift segmentation has been caused by reactivation of multiple basement structure systems which not only influence the orientation of rift segments and type of rift architecture, but also control the location, strike, dip and style of the major rift‐related faults. Rift segmentation was completely achieved through multiple phases of basement reactivation, while the main structural framework of segmentation was established through ‘extensive reactivation’ during the second phase extension. Our study examines how multiple basement structure systems control rift segmentation at both individual fault and sub‐basin scales, which can significantly improve our understanding of relationship between structural inheritance and rift segmentation.

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Structural inheritance in amagmatic rift basins: Manifestations and mechanisms for how pre-existing structures influence rift-related faults

Cited by 6 publications

References 279 publications

Influence of Inherited Brittle Fabrics on Continental Rifting: Insights From Centrifuge Experimental Modeling and Application to the East African Rift System

Influence of Inherited Brittle Fabrics on Continental Rifting: Insights From Centrifuge Experimental Modeling and Application to the East African Rift System

Metamorphic Inheritance, Lower‐Crustal Earthquakes, and Continental Rifting

Rift segmentation caused by reactivation of multiple basement structure systems: Evidence from the Hailar‐Tamtsag Rift, northeast Asia

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