Regional shortening followed by channel flow induced collapse: A new mechanism for “dome and keel” geometries in Neoarchaean granite-greenstone terrains

Harris, Lyal B.; Godin, Laurent; Yakymchuk, Chris

doi:10.1016/j.precamres.2012.04.022

Cited by 18 publications

(3 citation statements)

References 111 publications

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“…The characteristic deformation feature of the latter; large areas of monotonous strain patterns, HT-LP granulites showing isobaric P-Tt paths and extensive magmatism contributing to crustal growth are consistent with the hypothesis that these orogens formed above a relatively hotter mantle than that in the modern orogens and remained hot and mechanically weak during deformation over extended periods of time (Cagnard et al, 2006;Chardon et al, 2011;Chardon and Jayananda, 2008;Dumond et al, 2010). Thermomechanical and numerical experiments (Chardon et al, 2011;Chardon and Jayananda, 2008), indicate that convergence related deformation of hot and buoyant lithosphere produces distributed patterns of strain, lower topographic relief and high-and/ or ultrahigh temperature granulites (Cagnard et al, 2006;Harris et al, 2012;. Our preferred tectonic model for the Neoarchean Dharwar craton envisages the combined role of continental and oceanic arcs generating both juvenile and recycled crustal material between ~2.75 and 2.55 Ga.…”

Section: The Post-30 Ga Crust: Plate Tectonics and Terrane Assemblysupporting

confidence: 71%

A Review of Paleo- to Neoarchean crustal evolution in the Dharwar craton, Southern India and the transition towards a Plate Tectonic regime

et al. 2020

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Section: The Post-30 Ga Crust: Plate Tectonics and Terrane Assemblysupporting

confidence: 71%

A Review of Paleo- to Neoarchean crustal evolution in the Dharwar craton, Southern India and the transition towards a Plate Tectonic regime

et al. 2020

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“…2007; Castro & Gerya, 2008; Beccaluva et al . 2011), during continental collision and subsequent delamination of the thickened lithosphere (Tubía, Cuevas & Esteban, 2004) or in post-collisional settings (Harris, Godin & Yakymchuk, 2012). Slices of mantle rocks within the crust possibly occur in concomitance with trans-lithospheric shear processes (Vauchez, Tommasi & Mainprice, 2012) and are also testified by recent geophysical evidence that often highlights CMB offsets in several geological frameworks (Bastow et al .…”

Section: Resultsmentioning

confidence: 99%

Crustal xenoliths from Tallante (Betic Cordillera, Spain): insights into the crust–mantle boundary

2013

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The volcano of Tallante (Pliocene) in the Betic Cordillera (Spain) exhumed a heterogeneous xenolith association, including ultramafic mantle rocks and diverse crustal lithologies. The latter include metagabbroids and felsic rocks characterized by quartz-rich parageneses containing spinel ± garnet ± sillimanite ± feldspars. Pressure-temperature estimates for felsic xenoliths overlap (at 0.7-0.8 GPa) those recorded by the mantle-derived peridotite xenoliths. Therefore, we propose that an intimate association of interlayered crust and mantle lithologies characterizes the crust-mantle boundary in this area. This scenario conforms to evidence provided by the neighbouring massifs of Ronda and Beni Bousera (and by other peri-Mediterranean deep crust/mantle sections) where exhumation of fossil crustmantle boundary reveals that this boundary is not sharp. The results are discussed on the basis of recent geophysical and petrological studies emphasizing that in non-cratonic regions the crust-mantle boundary is often characterized by a gradational nature showing inter-fingering of heterogeneous lithologies. Silica-rich melts formed within the crustal domains intruded the surrounding mantle and induced metasomatism. The resulting hybrid crust-mantle domains thus provide suitable sources for exotic magma types such as the Mediterranean lamproites.

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“…These two tectonic scenarios are not fundamentally incompatible and might have occurred simultaneously in the same region (Lin, 2005). Density-driven tectonics resulted in formation of large-scale dome-and-keel structures that characterize Archean terrains (Chardon et al, 1996;Harris et al, 2012;Lana et al, 2010;Lin, 2005;Sandiford et al, 2004;Shackleton, 1995;Van Kranendonk et al, 2010). Interference folding has also been proposed as a mechanism to explain structural domes within the Archean Chinamora batholith in Zimbabwe (Snowden and Bickle, 1976).…”

Section: Introductionmentioning

confidence: 99%

Deformation coupling between the Archean Pukaskwa intrusive complex and the Hemlo shear zone, Superior Province, Canada

et al. 2013

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Archean greenstone belts typically form narrow sheared basins separating bulbous tonalo-trondjhemogranodioritic (TTG) intrusive complexes. The role played by gravity in the development of such dome-and-keel structures constitutes a key question in Archean tectonics. The Pukaskwa intrusive complex (PIC)-Hemlo greenstone belt system stands as a remarkable example of the dome-and-keel architecture that commonly occurs in Archean terrains. Abundant strain markers in the greenstone belt and in the Hemlo shear zone (HSZ) attest of late sinistral strike-slip kinematics (D 2 ) whereas, in general, the quartzofeldspathic coarse-grained rocks of the Pukaskwa intrusive complex bear little macroscopically visible kinematic indicators, most likely due to pervasive recrystallization. The PIC consists dominantly of a heterogeneous assemblage of TTG plutonic rocks and gneisses, which overall are less dense than the greenstone rocks. The study of anisotropy of magnetic susceptibility (AMS), based on 120 stations and 1947 specimens from the PIC, reveals east-west trending prolate and plano-linear fabrics across the northern margin of the complex, i.e., along the HSZ. Since geotherms were higher in the Archean than in the present, the effective viscosity of the TTG units would have been sufficiently low to allow their diapiric ascent through denser greenstone rocks. Here we propose an alternative model where thrust tectonics is responsible for the early structuration of the PIC. Later transpressive tectonics causes strain localization along internal strike-slip shear zones and along lithological boundaries.

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Regional shortening followed by channel flow induced collapse: A new mechanism for “dome and keel” geometries in Neoarchaean granite-greenstone terrains

Cited by 18 publications

References 111 publications

A Review of Paleo- to Neoarchean crustal evolution in the Dharwar craton, Southern India and the transition towards a Plate Tectonic regime

A Review of Paleo- to Neoarchean crustal evolution in the Dharwar craton, Southern India and the transition towards a Plate Tectonic regime

Crustal xenoliths from Tallante (Betic Cordillera, Spain): insights into the crust–mantle boundary

Deformation coupling between the Archean Pukaskwa intrusive complex and the Hemlo shear zone, Superior Province, Canada

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