Thermal Evolution of Asymmetric Hyperextended Magma‐Poor Rift Systems: Results From Numerical Modeling and Pyrenean Field Observations

Lescoutre, Rodolphe; Tugend, Julie; Brune, Sascha; Masini, Emmanuel; Manatschal, Giänreto

doi:10.1029/2019gc008600

Cited by 32 publications

(36 citation statements)

References 100 publications

(201 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As in the Mauléon basin, the paleothermal gradient decreases to 41.5°C/km near the edge of the Camèros basin, along with the intensity of the high temperature–low pressure metamorphism (Omodeo‐Salé et al, 2017). In the Mauléon basin, Lescoutre et al (2019) and Lescoutre et al (2019) have proposed that the paleogeothermal gradient had an asymmetric distribution in response to Early Cretaceous simple shear thinning. However, this study indicates that the Cretaceous paleogeothermal gradient was symmetric.…”

Section: Discussionmentioning

confidence: 99%

Paleogeothermal Gradients Across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)

et al. 2020

View full text Add to dashboard Cite

The fossil rift in the North Pyrenean Zone, which underwent high temperature-low pressure metamorphism and alkaline magmatism during Early Cretaceous hyperextension, was studied to explore the geothermal regime at the time of rifting. In this work, we combined Raman lab analysis and thermal numerical modelling to shed light on the distribution of geothermal gradients across the inverted hyperextended Mauléon rift basin during Albian and Cenomanian time, its period of active extension. Data were acquired from a set of 155 samples from densely spaced outcrops and boreholes, analyzed using Raman spectroscopy of carbonaceous material. The estimated paleogeothermal gradient is strongly related to the structural position along the Albian-Cenomanian rift, increasing along a proximal-distal margin transect from~34°C/km in the European proximal margin to~37-47°C/km in the two necking zones and 57-60°C/km in the hyperextended domain. This pattern of the paleogeothermal gradient induced a complex interaction between brittle and ductile deformation during crustal extension. A numerical model reproducing the thermal evolution of the North Pyrenees since 120 Ma suggests that mantle heat flow values may have reached 100 mW/m 2 during the rifting event. This model reveals that above the thermal pulse, the temperature gradient varied within a small range of 55 to 62°C/km, as inferred from RSCM peak temperatures. We demonstrate that the style of reactivation during subsequent convergence influenced the thermal structure of the inverted rift system.

show abstract

Section: Discussionmentioning

confidence: 99%

Paleogeothermal Gradients Across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Both interpretations indicate an oceanward migration in time and space of deformation. This migration is nowadays recognized in many margins and has been deduced from stratigraphic observations in the North Sea (Cowie et al, 2005;Walsh et al, 2003), Gulf of Corinth (Mattei et al, 2004), the Gulf of Suez (Gawthorpe et al, 2003), Alpine Tethys margins (Masini et al, 2013), the Mauleón-Arzacq basin (Western Pyrenees, Lescoutre et al, 2019), from fault and deformation kinematics in the West Iberia-Newfoundland margins (Pérez-Gussinyé & Ranero, 2005;Perón-Pinvidic et al, 2007;Ranero & Pérez-Gussinyé, 2010), and from numerical models of extension (Andrés-Martínez et al, 2019;Brune et al, 2014Brune et al, , 2017Ros et al, 2017).…”

Section: Introductionmentioning

confidence: 88%

Lithospheric Strength and Rift Migration Controls on Synrift Stratigraphy and Breakup Unconformities at Rifted Margins: Examples From Numerical Models, the Atlantic and South China Sea Margins

et al. 2020

View full text Add to dashboard Cite

Synrift stratigraphy and the distribution of breakup-related erosional unconformities vary vastly between passive margins and cannot be explained by classical rifting models. Here we use numerical modeling to predict their spatiotemporal distribution. We show that synrift stratigraphy mimics rift architecture, which is controlled by lithospheric strength. Basinward rift migration during extension produces (1) oceanward younging, syntectonic and posttectonic sequences, (2) rift migration unconformities, RMUs, predating breakup, and (3) a breakup unconformity, BU, that only extends over the outermost margins, since breakup is not linked with a sudden stress drop. With small synrift sedimentation, the RMUs and BU laterally merge to form a margin-wide unconformity. In symmetric, wide conjugate margins, which arise for weak lithospheres such as the South China Sea, a long phase of distributed deformation with little subsidence results in early synrift sediment over most of the margins. RMUs merge into a single event that marks the subsequent focusing of deformation into a narrow breakup area, which experiences short-lived intense thinning and subsidence. In asymmetric conjugate margins, lateral rift migration transports shallowly deposited, early synrift sediments from the narrow to the wide, hyperextended margin, leading to a condensed syntectonic sequence and a single BU in the narrow margin and a series of RMUs in the wide one. For very weak lower crusts, lateral rift migration generates large synrift sag basins in the wide margin, as in Angola and Congo margins. Our models resemble the observed margins tectonic diversity and may be used as templates for interpreting their distal, unexplored areas.

show abstract

“…Classifying conjugate rifted margins in terms of their symmetry is a fundamental approach for analyzing the geodynamics of rifted margin formation (Huismans and Beaumont, 2003;Nagel and Buck, 2004;Reston, 2009;Brune et al, 2014;Lescoutre et al, 2019). The crustal rheology and extension rate control the rifting styles and final architectures of margins (Tetreault and Buiter, 2017).…”

Section: Introductionmentioning

confidence: 99%

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

Bai

Wang

Dong

et al. 2020

Marine and Petroleum Geology

Self Cite

View full text Add to dashboard Cite

The symmetry of conjugate rifted margins is a first-order observable feature reflecting the geodynamic processes acting during and after continental rifting. The symmetry of the South China Sea (SCS) rifted margins can be deduced from comprehensive geophysical datasets on a continental-margin scale. Here, we combine three key approaches: (1) lateral fault distributions are delineated according to free-air gravity anomalies, (2) crustal stretching styles are mapped based on gravity inversion constrained by deep seismic profiles, and (3) total extensions of conjugate margins are estimated according to margin restorations and tectonic settings. We infer a predominantly symmetric rifting style caused by pure shear extension, with only narrow domains of asymmetric deformation in continent-ocean transition (COT) regions that have undergone simple shear and where the lower crust of the highly thinned distal margin is embrittled before continental breakup. However, our analysis also suggests that this symmetry has been modified by post-rift geodynamic processes. Southward lower crustal flow, which occurred only on the southern margin due to the low viscosity of the lower crust and the slab pull induced by the subducting Proto-SCS plate during seafloor spreading, shifted the crustal stretching styles from symmetric to asymmetric. The collision between the southern margin and Borneo thickened the lower crust more than the upper crust at the southern end of the southern margin and shortened the southern margin. This event had a large impact on the SE margin but a small impact on the SW margin. We conclude that (1) for the SE and NE margins, the crustal stretching styles shifted from asymmetric to approximately symmetric, and the total extensions shifted from symmetric to asymmetric; (2) for the SW and NW margins, the crustal stretching and total extensions remained asymmetric and symmetric, respectively.

show abstract

Thermal Evolution of Asymmetric Hyperextended Magma‐Poor Rift Systems: Results From Numerical Modeling and Pyrenean Field Observations

Cited by 32 publications

References 100 publications

Paleogeothermal Gradients Across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)

Paleogeothermal Gradients Across an Inverted Hyperextended Rift System: Example of the Mauléon Fossil Rift (Western Pyrenees)

Lithospheric Strength and Rift Migration Controls on Synrift Stratigraphy and Breakup Unconformities at Rifted Margins: Examples From Numerical Models, the Atlantic and South China Sea Margins

Symmetry of the South China Sea conjugate margins in a rifting, drifting and collision context

Contact Info

Product

Resources

About