Oceanic plateau accretion onto the northwestern margin of the Yilgarn Craton, Western Australia

Pirajno, Franco

doi:10.1016/j.jog.2004.02.003

Cited by 16 publications

(2 citation statements)

References 59 publications

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“…Geochemical mixing between mantle and lithospheric material (as for the "slab-like" lithospheric instability) would also fit the geochronological and petrological constraints detailed in Abouchami et al (1990). In Western Australia, a similar scenario with a mantle plume event at 2.0 Ga around cratonic areas, has also been suggested by Pirajno (2004).…”

Section: Lithospheric Instabilities and Crustal Growthmentioning

confidence: 67%

Plume head–lithosphere interactions near intra-continental plate boundaries

et al. 2007

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Plume-lithosphere interactions (PLI) have important consequences both for tectonic and mineralogical evolution of the lithosphere: for example, Archean metallogenic crises at the boundaries of the West African and Australian cratons coincide with postulated plume events. In continents, PLI are often located near boundaries between younger plates (e.g., orogenic) and older stable plates (e.g., cratons), which represent important geometrical, thermal and rheological barriers that interact with the emplacement of the plume head (e.g., Archean West Africa, East Africa, Pannonian-Carpathian system). The observable PLI signatures are conditioned by plume dynamics but also by lithosphere rheology and structure. We address the latter problem by considering a free-surface numerical model of PLI with two stratified elastoviscous-plastic (EVP) lithospheric plates, one of which is older and thicker than another. The results show that: (1) plume head flattening is asymmetric, it is blocked from one side by the cold vertical boundary of the older plate, which leads to the mechanical decoupling of the crust from the mantle lithosphere, and to localized faulting at the cratonic margin; (2) the return flow from the plume head results in sub-vertical downthrusting (delamination) of the lithosphere at the margin, producing sharp vertical cold boundary down to the 400 km depth; (3) plume head flattening and migration towards the younger plate results in concurrent surface extension above the centre of the plume and in compression (pushing), down-thrusting and magmatic events at the cratonic margin (down-thrusting is also produced at the opposite border of the younger plate); these processes may result in continental growth at the "craton side"; (4) topographic signatures of PLI show basin-scale uplifts and subsidences preferentially located at cratonic margins. Negative Rayleigh-Taylor instabilities in the lithosphere above the plume head provide a mechanism for crustal delamination. Inferred consequences of PLI near intra-continental plate boundaries, such as faulting at cratonic edges and enhanced magmatic activity, could explain plume-related metallogenic crises, as suggested for West Africa and Australia.

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Section: Lithospheric Instabilities and Crustal Growthmentioning

confidence: 67%

Plume head–lithosphere interactions near intra-continental plate boundaries

et al. 2007

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“…The UB rocks have been interpreted as: (i) part of ophiolitic complexes (Furnes et al, 2015); (ii) relics of Large Igneous Province-type Layered Complex associated to deep continental crust (Yu et al, 2015;Grant et al, 2016) or arcs settings (Jagoutz et al, 2006;Burg et al, 2009); (iii) roots of ultrabasic-basic (UB-B) arc complexes like Alaskan-type (Grant et al, 2016;Yuan et al, 2017). Moreover, their formation have been associated with various geodynamic environments: i) back-arc suprasubduction zone ophiolite (Myers et al, 1996;Furnes et al, 2015); ii) plume-enhanced back-arc basin (Pirajno and Occhipinti, 2000); iii) an oceanic plateau (Pirajno, 2004); iv) an intracontinental rift setting (Olierook et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Petrological and geochemical study of Birimian ultramafic rocks within the West African Craton: Insights from Mako (Senegal) and Loraboué (Burkina Faso) lherzolite/harzburgite/wehrlite associations

Labou

Benoît

Baratoux

et al. 2020

Journal of African Earth Sciences

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In Archean and Paleoproterozoic greenstone belts, ultrabasic (UB) rock occurrences are commonly found in close association within basic and differentiated magmatic series. In the Kedougou inlier (West African Craton), UB rocks are interbeded within the Birimian (2.1 Ga) Mako tholeiitic series (basalts, gabbros). UBs are typically lherzolite, harzburgite and wehrlite, characterized by their cumulative textures and relative proportions of chromite, olivine, clinopyroxene, amphibole ± orthopyroxene. Geochemical study (Major, REE and trace elements in whole rocks and mineral (mainly clinopyroxene and amphibole) and Sr/Nd isotopic records suggest the existence of different types of complexes. The first one consists of lherzolite + harzburgite assemblages whereas the second one consists of isolated wehrlite massifs. Both complexes highlight two different geodynamic environments, the first association being significantly more juvenile or mantle-related than isolated wehrlites which show more evolved geochemical signatures. UB rocks (dunite + wehrlite) of Loraboué (greenstone belt of Boromo, Burkina Faso) associated with calc-alcaline series display the same mineralogical composition as the Mako UB rocks but exhibit a different whole rock composition characteristics of mature island-arc magmas and showing U-shaped REE pattern for both clinopyroxene and host rock, and a clear negative Nb anomaly. The Mako UBs suggest that this portion of the Birimian crust was built in an oceanic context evolving from a MORB-like domain to an increasingly mature volcanic arc domain.

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Submarine Hydrothermal Mineral Systems

Pirajno

2009

Hydrothermal Processes and Mineral Systems

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Oceanic plateau accretion onto the northwestern margin of the Yilgarn Craton, Western Australia

Cited by 16 publications

References 59 publications

Plume head–lithosphere interactions near intra-continental plate boundaries

Plume head–lithosphere interactions near intra-continental plate boundaries

Petrological and geochemical study of Birimian ultramafic rocks within the West African Craton: Insights from Mako (Senegal) and Loraboué (Burkina Faso) lherzolite/harzburgite/wehrlite associations

Submarine Hydrothermal Mineral Systems

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