Shear-driven upwelling induced by lateral viscosity variations and asthenospheric shear: A mechanism for intraplate volcanism

Conrad, Clinton P.; Wu, Buyun; Smith, Eugene I.; Bianco, T. A.; Tibbetts, A. K.

doi:10.1016/j.pepi.2009.10.001

Cited by 101 publications

(118 citation statements)

References 75 publications

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“…The latter also apply for rocks of the same age cropping out in different locations. Because the development of the magmatic province encompasses the stage of fast westward drift of South America, we propose that shear-driven upwelling (Conrad et al, 2010) is a geodynamic process to take into account as a possible contributing mechanism when analyzing the genesis of most of these backarc to intraplate lavas.…”

Section: Discussionmentioning

confidence: 99%

“…Shear-driven upwelling (Conrad et al, 2010) is another mechanism that may be applied to the petrogenesis of any of the Late Cretaceous to Cenozoic Patagonian back-arc lavas irrespective of their rock ages. Plate motion requires shearing between the westward moving lithosphere and the asthenosphere.…”

Section: On Tectonomagmatic Models From the Patagonian Plateu Basaltsmentioning

confidence: 99%

“…These irregularities in the lithosphere-asthenosphere plane would imply the presence of lateral viscosity heterogeneities. Analysing classic engineering problems, Conrad et al (2010) concluded that rapid shearing in a lithosphere-asthenosphere zone having asperities (i.e., lateral viscosity heterogeneities) will induce circulatory flow within cavities, facilitating magma upwelling (Fig. 6).…”

Section: On Tectonomagmatic Models From the Patagonian Plateu Basaltsmentioning

confidence: 99%

“…Additionally, South America began to move fast to the west with respect to the underlying mantle at 90-95 Ma (Somoza and Zaffarana, 2008) and continued throughout the entire Cenozoic, matching the timing of back-arc volcanism in Patagonia. Then, the Late Cretaceous to Recent mafic volcanic province of Patagonia developed above a rapidly shearing asthenosphere, making shear-driven upwelling (Conrad et al, 2010) a geodynamic process capable to contribute in the genesis of most of these back-arc to intraplate lavas.…”

Section: On Tectonomagmatic Models From the Patagonian Plateu Basaltsmentioning

confidence: 99%

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Paleomagnetism and geochemistry from the Upper Cretaceous Tres Picos Prieto locality (43ºS), Patagonian Plateau Basalts

Zaffarana¹,

Lagorio²,

Somoza³

2012

Andgeo

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ABSTRACT.A paleomagnetic study on nine samples from lavas from the Upper Cretaceous Tres Picos Prieto locality (43º50'S and 70º3'W), Patagonian Plateau Basaltic Province, revealed that a ca. 300 m thick pile of basalts accumulated during three discrete (i.e., temporally separated) volcanic episodes. The chemistry of these lavas shows characteristics compatible with both subduction and intraplate magmatism, with the former having a more important contribution in the younger lavas. Overall, we interpret these rocks to be transitional basalts generated in a supra-subduction environment. The Late Cretaceous to Cenozoic Patagonian Plateau Basaltic Province crops out from eastern Patagonia to the cordillera, and their genesis have been associated with different tectonic processes, even for spatially separated rocks of the same age. Considering that the development of the magmatic province is contemporary with the stage of westward drift of South America, we propose that magma generation and upwelling due to rapidly shearing asthenosphere inducing circulatory flow associated to asperities in the lithosphere-asthenosphere interface (shear-driven upwelling) can be evaluated as a further potential mechanism to account for many outcrops of these backarc to intraplate lavas.

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Section: Discussionmentioning

confidence: 99%

Section: On Tectonomagmatic Models From the Patagonian Plateu Basaltsmentioning

confidence: 99%

Section: On Tectonomagmatic Models From the Patagonian Plateu Basaltsmentioning

confidence: 99%

Section: On Tectonomagmatic Models From the Patagonian Plateu Basaltsmentioning

confidence: 99%

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Paleomagnetism and geochemistry from the Upper Cretaceous Tres Picos Prieto locality (43ºS), Patagonian Plateau Basalts

Zaffarana¹,

Lagorio²,

Somoza³

2012

Andgeo

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“…Forsyth et al 2006), small-scale sublithospheric convection (e.g. Ballmer et al 2009), or shear-induced melting of low-viscosity pockets of asthenospheric mantle located along the base of the lithosphere (Conrad et al 2010).…”

mentioning

confidence: 99%

Seamounts and oceanic igneous features in the NE Atlantic: a link between plate motions and mantle dynamics

Gaina

Blischke

Geissler

et al. 2016

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A new regional compilation of seamount-like oceanic igneous features (SOIFs) in the NE Atlantic points to three distinct oceanic areas of abundant seamount clusters. Seamounts on oceanic crust dated 54-50 Ma are formed on smooth oceanic basement, which resulted from high spreading rates and magmatic productivity enhanced by higher than usual mantle plume activity. Late Eocene-Early Miocene SOIF clusters are located close to newly formed tectonic features on rough oceanic crust in the Irminger, Iceland and Norway basins, reflecting an unstable tectonic regime prone to local readjustments of mid-ocean ridge and fracture zone segments accompanied by extra igneous activity. A SOIF population observed on Mid-Miocene-Present rough oceanic basement in the Greenland and Lofoten basins, and on conjugate Kolbeinsey Ridge flanks, coincides with an increase in spreading rate and magmatic productivity. We suggest that both tectonic/kinematic and magmatic triggers produced Mid-Miocene-Present SOIFs, but the Early Miocene westwards ridge relocation may have played a role in delaying SOIF formation south of the Jan Mayen Fracture Zone. We conclude that Iceland plume episodic activity combined with regional changes in relative plate motion led to local mid-ocean ridge readjustments, which enhanced the likelihood of seamount formation.

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Dynamics of lithospheric thinning and mantle melting by edge‐driven convection: Application to Moroccan Atlas mountains

Kaislaniemi

Hunen

2014

Geochem Geophys Geosyst

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Edge-driven convection (EDC) forms in the upper mantle at locations of lithosphere thickness gradients, e.g., craton edges. In this study we show how the traditional style of EDC, a convection cell governed by the cold downwelling below an edge alternates with another style of EDC, in which the convection cell forms as a secondary feature with a hot asthenospheric shear flow from underneath the thicker lithosphere. These alternating EDC styles produce episodic lithosphere erosion and decompression melting. Three-dimensional models of EDC show that convection rolls form perpendicular to the thickness gradient at the lithosphere-asthenosphere boundary. Stagnant-lid convection scaling laws are used to gain further insight in the underlying physical processes. Application of our models to the Moroccan Atlas mountains region shows that the combination of these two styles of EDC can reproduce many of the observations from the Atlas mountains, including two distinct periods of Cenozoic volcanism, a semicontinuous corridor of thinned lithosphere under the Atlas mountains, and piecewise delamination of the lithosphere. A very good match between observations and numerical models is found for the lithosphere thicknesses across the study area, amounts of melts produced, and the length of the quiet gap in between volcanic episodes show quantitative match to observations.

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Shear-driven upwelling induced by lateral viscosity variations and asthenospheric shear: A mechanism for intraplate volcanism

Cited by 101 publications

References 75 publications

Paleomagnetism and geochemistry from the Upper Cretaceous Tres Picos Prieto locality (43ºS), Patagonian Plateau Basalts

Paleomagnetism and geochemistry from the Upper Cretaceous Tres Picos Prieto locality (43ºS), Patagonian Plateau Basalts

Seamounts and oceanic igneous features in the NE Atlantic: a link between plate motions and mantle dynamics

Dynamics of lithospheric thinning and mantle melting by edge‐driven convection: Application to Moroccan Atlas mountains

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