Rifted margin architecture and crustal rheology: Reviewing Iberia-Newfoundland, Central South Atlantic, and South China Sea

Brune, Sascha; Heine, Christian; Clift, Peter D.; Pérez‐Gussinyé, M.

doi:10.1016/j.marpetgeo.2016.10.018

Cited by 169 publications

(141 citation statements)

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“…We use a nonlinear viscous flow (dislocation creep) and Drucker‐Prager plasticity for the model rheology and follow a setup similar to previous studies (e.g., Brune et al, ; Brune et al, ;Huismans & Beaumont, ; Naliboff & Buiter, ). The viscosity for dislocation creep is defined as follows:

μ_{d i s l} = \frac{1}{2} A^{- \frac{1}{n}} {\overset{ε_{e}}{true}}^{\frac{false(1 - n false)}{n}} \exp ((), \frac{E + P V}{n R T})

where A is the viscosity prefactor, n is the stress exponent ( n > 1),

\overset{ε_{e}}{true}

is the square root of the deviatoric strain rate tensor second invariant, E is activation energy, V is activation volume, and R is the gas exponent (Karato & Wu, ; Karato, ).…”

Section: Methodsmentioning

confidence: 99%

Segmentation of Rifts Through Structural Inheritance: Creation of the Davis Strait

et al. 2019

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Mesozoic‐Cenozoic rifting between Greenland and North America created the Labrador Sea and Baffin Bay, while leaving preserved continental lithosphere in the Davis Strait, which lies between them. Inherited crustal structures from a Palaeoproterozoic collision have been hypothesized to account for the tectonic features of this rift system. However, the role of mantle lithosphere heterogeneities in continental suturing has not been fully explored. Our study uses 3‐D numerical models to analyze the role of crustal and subcrustal heterogeneities in controlling deformation. We implement continental extension in the presence of mantle lithosphere suture zones and deformed crustal structures and present a suite of models analyzing the role of local inheritance related to the region. In particular, we investigate the respective roles of crust and mantle lithospheric scarring during an evolving stress regime in keeping with plate tectonic reconstructions of the Davis Strait. Numerical simulations, for the first time, can reproduce first‐order features that resemble the Labrador Sea, Davis Strait, Baffin Bay continental margins, and ocean basins. The positioning of a mantle lithosphere suture, hypothesized to exist from ancient orogenic activity, produces a more appropriate tectonic evolution of the region than the previously proposed crustal inheritance. Indeed, the obliquity of the continental mantle suture with respect to extension direction is shown here to be important in the preservation of the Davis Strait. Mantle lithosphere heterogeneities are often overlooked as a control of crustal‐scale deformation. Here, we highlight the subcrust as an avenue of exploration in the understanding of rift system evolution.

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μ_{d i s l} = \frac{1}{2} A^{- \frac{1}{n}} {\overset{ε_{e}}{true}}^{\frac{false(1 - n false)}{n}} \exp ((), \frac{E + P V}{n R T})

where A is the viscosity prefactor, n is the stress exponent ( n > 1),

\overset{ε_{e}}{true}

is the square root of the deviatoric strain rate tensor second invariant, E is activation energy, V is activation volume, and R is the gas exponent (Karato & Wu, ; Karato, ).…”

Section: Methodsmentioning

confidence: 99%

Segmentation of Rifts Through Structural Inheritance: Creation of the Davis Strait

et al. 2019

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“…involves crustal thickness variations (Harry and Grandel, 2007), strain softening (Brune et al, 2014;2017) or structural softening of the crust and sub-Moho mantle (Duretz et al, 2016). In absence of one of these factors, the overall deformation pattern is symmetrical in both analogue (Brun andBeslier, 1996, Nestola et al, 2013; and numerical (Nagel and Buck, 2004;Lavier and Manatchal, 2006;Burov, 2007b;Weinberg et al, 2007;Beaumont and Ings, 2012) models.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Crustal versus mantle core complexes

et al. 2018

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Contrary to what is commonly believed, it is argued from analogue and numerical models that detachments that accommodate exhumation of core complexes do not initiate at the onset of extension but in the course of progressive extension when the exhuming ductile crust reaches the surface. In models, convex upward detachments result from a rolling hinge process. A C C E P T E D M A N U S C R I P TMantle core complexes develop in either the oceanic lithosphere, at slow and ultra-slow spreading ridges, or in continental lithospheres, whose initial Moho temperature is lower than 750°C, with "sub-Moho mantle-dominated" strength profiles. It is argued that the mechanism of mantle exhumation at passive margins is a nearly symmetrical necking process at ACCEPTED MANUSCRIPTA C C E P T E D M A N U S C R I P T 2 lithosphere scale without major and permanent detachment, except if strong strain localization could occur in the lithosphere mantle. Distributed crustal extension, by upper crust faulting above a décollement along the ductile crust increases toward the rift axis up to crustal breakup.Mantle rocks exhume in the zone of crustal breakup accommodated by conjugate mantle shear zones that migrate with the rift axis, during increasing extension.

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“…Other examples of highly extended rifted margins have been identified in seismic reflection data elsewhere (e.g., Brune et al, 2017;Doré and Lundin, 2015). However, it is not known if serpentinized mantle plays a critical role in all cases.…”

Section: Global Questions Regarding Formation Of Rifted Marginsmentioning

confidence: 99%

Expedition 367 Preliminary Report: South China Sea Rifted Margin

Sun¹,

Stock²,

Klaus³

2018

International Ocean Discovery Program Preliminary Report

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International Ocean Discovery Program Expedition 367 is the first of two consecutive cruises that form the South China Sea Rifted Margin program. Expeditions 367 and 368 share the common key objectives of testing scientific hypotheses of breakup of the northern South China Sea (SCS) margin and comparing its rifting style and history to other nonvolcanic or magma-poor rifted margins. Four primary sites were selected for the overall program: one in the outer margin high (OMH) and three seaward of the OMH on distinct, margin-parallel basement ridges. These ridges are informally labeled A, B, and C within the continent-ocean transition (COT) zone going from the OMH to the steady-state oceanic crust of the SCS. The main scientific objectives include 1. Determining the nature of the basement within critical crustal units across the COT of the SCS that are critical to constrain style of rifting, 2. Constraining the time interval from initial crustal extension and plate rupture to the initial generation of igneous ocean crust, 3. Constraining vertical crustal movements during breakup, and 4. Examining the nature of igneous activity from rifting to seafloor spreading.In addition, sediment cores from the drill sites will provide information on the Cenozoic regional tectonic and environmental development of the Southeast Asia margin.Expedition 367 successfully completed operations at two of the four primary sites (Site U1499 on Ridge A and Site U1500 on Ridge B). At Site U1499, we cored to 1081.8 m in 22.1 days, with 52% recovery, and then logged downhole data from 655 to 1020 m. In 31 days at Site U1500, we penetrated to 1529 m, cored a total of 1012.8 m with 37% recovery, and collected log data from 842 to 1133 m. At each site we drilled to reach the depth of the main seismic reflector (acoustic basement), which prior to the expedition had been interpreted to be crystalline basement. Our objective was to determine which lithospheric layer constitutes the basement of the COT and whether there was middle or lower continental crust or subcontinental lithospheric mantle exhumed in the COT before the final lithospheric breakup. At Site U1499, coring ~200 m into the acoustic basement sampled sedimentary rocks, including early Miocene chalks underlain by pre-Miocene polymict breccias and poorly cemented gravels composed of sandstone pebbles and cobbles. Preliminary structural and lithologic analysis suggested that the gravels might be early synrift to prerift sediment. At Site U1500, the main seismic reflector corresponds to the top of a basalt sequence at ~1379.1 m. We cored 149.90 m into this volcanic package, recovering 114.92 m (77%) of sparsely to moderately plagioclase-phyric basalt comprising numerous lava flows including pillow lavas with glass, chilled margins, altered veins, hyaloclastites, and minor sediment. Preliminary geochemical analyses show that the basalt is tholeiitic. We speculate that the basalt might belong to the very early stage of magmatism prior to steady-state seafloor spreading (known as an "...

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Rifted margin architecture and crustal rheology: Reviewing Iberia-Newfoundland, Central South Atlantic, and South China Sea

Cited by 169 publications

References 275 publications

Segmentation of Rifts Through Structural Inheritance: Creation of the Davis Strait

Segmentation of Rifts Through Structural Inheritance: Creation of the Davis Strait

Crustal versus mantle core complexes

Expedition 367 Preliminary Report: South China Sea Rifted Margin

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