Riccardo ASTI

Control of mantle dynamics on Iberian and Mediterranean basins 

Supervisor:
Yves Lagabrielle – Université de Rennes

Major Results

A detailed field study was conducted on exceptionally preserved Cretaceous distal margin analogs in two key areas of the western Pyrenees (North Pyrenean Zone): the Urdach and Saraillé ultramafic massifs in the Chaînons Béarnais range The importance of the crustal structure inherited from previous Paleozoic and Mesozoic tectonic events is highlighted and it is interpreted that mantle exhumation was partially achieved before the Cretaceous North Pyrenean rifting.

Abstract

Extreme crustal thinning associated with subcontinental mantle exhumation characterizes the distal domain of some current, magma‐poor continental passive margins. Since these domains lie at abyssal depths and are hardly accessible, their internal structure and the finite strain of the stretched crust are not directly observed and are only inferred. A tight sampling allowed us to characterize the conditions of the ductile deformation of the continental crust exhumed together with the mantle.

 

New 40Ar/39Ar dating on muscovite constrains the timing of the last deformation of the continental crust in relation with mantle exhumation to the late Albian. We propose a new reconstruction for the distal part of the North Iberian paleopassive margin.
Conceptual reconstruction of the distal domain of the North Iberian paleopassive margin at mid‐Cretaceous times as constrained from the data presented in this study. Thin mylonitic pre‐Silurian crustal lenses are exhumed together with the mantle at the floor of the Albian‐Cenomanian basin; these are locally reworked together in in clastic deposits interfingered with the late Albian tubidites (e.g., Urdach Breccia). The granulitic lower crust is extracted laterally and is left behind in the proximal margin domain. The Mesozoic prerift cover glide on a decollement layer represented by the late Triassic evaporites (Keuper) and are locally put in direct contact with the exhumed mantle in the distal domain (e.g., Saraillé massif). Clastic deposits reworking post‐Silurian and Mesozoic prerift deposits (e.g., Mendibelza conglomerate) onlap the proximal margin that is simply tilted basinward, without the development of major tilted blocks.

Review of Iberia-Eurasia plate-boundary basins: Role of sedimentary burial on depth-dependent continental crust ductile thinning during rifting and continental breakup.

Review of Iberia-Eurasia plate-boundary basins: Role of sedimentary burial on depth-dependent continental crust ductile thinning during rifting and continental breakup.

N. Saspiturry, B. Issautier, P. Razin, T. Baudin, R. Asti, Y. Lagabrielle, C. Allanic, O. Serrano, (2021), Review of Iberia-Eurasia plate-boundary basins: Role of sedimentary burial on depth-dependent continental crust ductile thinning during rifting and continental breakup. Basin Research. 

keywords: Iberian-European boundary; Sedimentary burial; Salt tectonics; Depth-dependent thinning; Ductile regime; HT/LP metamorphism

DOI: https://doi.org/10.1111/bre.12529

A review of Cretaceous smooth-slopes-extensional basins along the Iberia-Eurasia plate boundary: how prerift salt controls the modes of continental rifting and mantle exhumation.

A review of Cretaceous smooth-slopes-extensional basins along the Iberia-Eurasia plate boundary: how prerift salt controls the modes of continental rifting and mantle exhumation.

Y. Lagabrielle, R. Asti, T. Duretz, C. Clerc, S. Fourcade, A. Teixell, P. Labaume, B. Corre, N. Saspiturry, (2020), A review of Cretaceous smooth-slopes-extensional basins along the Iberia-Eurasia plate boundary: how prerift salt controls the modes of continental rifting and mantle exhumation. Earth Science Review. 

keywords: Smooth-slopes basins; symmetrical profile; Iberia; Eurasia; Triassic evaporites; décollement layer; thermal anomaly; sedimentary burial; dominating-ductile tectonic regime

DOI: https://doi.org/10.1016/j.earscirev.2019.103071

A reconstruction of Iberia accounting for Western Tethys/N-Atlantic kinematics since the late Permian-Triassic

A reconstruction of Iberia accounting for Western Tethys/N-Atlantic kinematics since the late Permian-Triassic

Angrand, P., Mouthereau, F., Masini, E., Asti, R. (2020). A reconstruction of Iberia accounting for W-Tethys/N-Atlantic kinematics since the late Permian-Triassic. Solid Earth, European Geosciences Union, inPress, ⟨10.5194/se-2020-24⟩. ⟨insu-02865944⟩

keywords:  plate kinematics, Iberia, Mesozoic Cenozoic, Geodynamics, Ebro block, Central Iberian Range, Pyrenees

DOI: https://dx.doi.org/10.5194/se-2020-24

How do continents deform during mantle exhumation? Insights from the northern Iberia inverted paleopassive margin, western Pyrenees (France).

How do continents deform during mantle exhumation? Insights from the northern Iberia inverted paleopassive margin, western Pyrenees (France).

Asti, R., Lagabrielle, Y., Fourcade, S., Corre, B., & Monié, P. (2019). How do continents deform during mantle exhumation? Insights from the northern Iberia inverted paleopassive margin, western Pyrenees (France). Tectonics, 38, 1666–1693.

keywords:  mantle exhumation, Pyrenees, hyperextension, passive margins

DOI: https://doi. org/10.1029/2018TC005428

Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn‐rift salt tectonics 

Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation and syn‐rift salt tectonics

Duretz, T., Asti, R., Lagabrielle, Y., Brun, J-P., Jourdon, A.. (2019).Numerical modelling of Cretaceous Pyrenean Rifting: The interaction between mantle exhumation
and syn-rift salt tectonics. Basin Res. 2020;32: 652–667.

keywords:  North Pyrenean rifting, numerical modeling, décollement, syn-rift salt tectonics, mantle exhumation, high temperature metamorphism

DOI: https://doi.org/10.1111/bre.12389

Mantle exhumation at magma-poor passive continental margins. Part II: Tectonic and metasomatic evolution of large-displacement detachment faults preserved in a fossil distal margin domain (Saraillé lherzolites, northwestern Pyrenees, France)

Mantle exhumation at magma-poor passive continental margins. Part II: Tectonic and metasomatic evolution of large-displacement detachment faults preserved in a fossil distal margin domain (Saraillé lherzolites, northwestern Pyrenees, France)

Lagabrielle, Y., Asti, R., Fourcade, S., Corre, B., Labaume, P., Uzel, J., … & Picazo, S. (2019). Mantle exhumation at magma-poor passive continental margins. Part II: Tectonic and metasomatic evolution of large-displacement detachment faults preserved in a fossil distal margin domain (Saraillé lherzolites, northwestern Pyrenees, France). Bulletin de la Société Géologique de France, 190(1).

keywords:  North Pyrenean Zone, Saraillé, mantle exhumation, fluid-rock interactions, talc-chlorite schists, greenschist facies, detachment faults, mid-Late Cretaceous

DOI: https://doi.org/10.1051/bsgf/2019013

Mantle exhumation at magma-poor passive continental margins. Part I. 3D architecture and metasomatic evolution of a fossil exhumed mantle domain (Urdach lherzolite, north-western Pyrenees, France)  

Mantle exhumation at magma-poor passive continental margins. Part I. 3D architecture and metasomatic evolution of a fossil exhumed mantle domain (Urdach lherzolite, north-western Pyrenees, France)

Lagabrielle, Y., Asti, R., Fourcade, S., Corre, B., Labaume, P., Uzel, J., … & Picazo, S. (2019) Mantle exhumation at magma-poor passive continental margins. Part I. 3D architecture and metasomatic evolution of a fossil exhumed mantle domain (Urdach lherzolite, north-western Pyrenees, France) ; BSGF Earth Sciences Bulletin 2019, 190, 8

keywords:  North Pyrenean Zone, Urdach, mantle exhumation, fluid-rock interactions, listvenites, greenschist facies, detachment faults, Late Cretaceous

DOI: https://dx.doi.org/10.1051/bsgf/2019007