Archean mantle plumes: Evidence from greenstone belt geochemistry

Tomlinson, K Y; Condie, Kent C.

doi:10.1130/0-8137-2352-3.341

Cited by 42 publications

(17 citation statements)

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“…Arndt et al. , 2001; Tomlinson and Condie, 2001; Condie, 2005). The presence of komatiite flows within generally basaltic sequences is another argument typically used as evidence for a mantle plume origin, because of the very high temperatures thought to be required to produce komatiitic magmas, at great depth in particularly hot mantle plumes (e.g.…”

Section: Secular Geochemical Trends As Indicators Of Tectonic Processesmentioning

confidence: 99%

Review: secular tectonic evolution of Archean continental crust: interplay between horizontal and vertical processes in the formation of the Pilbara Craton, Australia

et al. 2007

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The Archean Pilbara Craton contains five geologically distinct terranes – the East Pilbara, Karratha, Sholl, Regal and Kurrana Terranes – all of which are unconformably overlain by the 3.02‐ to 2.93‐Ga De Grey Superbasin. The 3.53–3.17 Ga East Pilbara Terrane (EP) represents the ancient nucleus of the craton that formed through three distinct mantle plume events at 3.53–3.43, 3.35–3.29 and 3.27–3.24 Ga. Each plume event resulted in eruption of thick dominantly basaltic volcanic successions on older crust to 3.72 Ga, and melting of crust to generate first tonalite‐trondhjemite‐granodiorite (TTG), and then progressively more evolved granitic magmas. In each case, plume magmatism was accompanied by uplift and crustal extension. The combination of conductive heating from below, thermal blanketing from above, and internal heating of buried granitoids during these events led to episodes of partial convective overturn of upper and middle crust. These mantle melting events caused severe depletion of the subcontinental lithospheric mantle, making the EP a stable, buoyant, unsubductable continent by c. 3.2 Ga. Extension accompanying the latest event led to rifting of the protocontinent margins at between 3.2 and 3.17 Ga. After 3.2 Ga, horizontal tectonic forces dominated over vertical forces, as revealed by the geology of the three terranes (Karratha, Sholl and Regal) of the West Pilbara Superterrane. The c. 3.12‐Ga Whundo Group of the Sholl Terrane is a fault bounded, 10‐km‐thick volcanic succession with geochemical characteristics of modern oceanic arcs (including boninites and evidence for flux melting) that indicate steep Archean subduction. At 3.07 Ga, the 3.12‐Ga Sholl Terrane, 3.27‐Ga Karratha Terrane and c. 3.2‐Ga Regal Terrane accreted together and onto the EP during the Prinsep Orogeny. This was followed by development of the De Grey Superbasin – an intracontinental sag basin and widespread plutonism (2.99–2.93 Ga) as a result of orogenic relaxation and slab break off. Craton‐wide compressional deformation at 2.95–2.93 Ga culminated with 2.91‐Ga accretion of the 3.18 Ga Kurrana Terrane with the EP. This compression caused amplification of the dome‐and‐keel structure in the EP. Final cratonization was effected by emplacement of 2.89–2.83 Ga post‐tectonic granites.

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Section: Secular Geochemical Trends As Indicators Of Tectonic Processesmentioning

confidence: 99%

Review: secular tectonic evolution of Archean continental crust: interplay between horizontal and vertical processes in the formation of the Pilbara Craton, Australia

et al. 2007

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“…In this section, we address high-Mg magmas (komatiites and meimechites with MgO > 18% and picrites with MgO = 12%-18%) (Le Bas 2000), which are considered diagnostic of plumes (e.g., Campbell 1998Campbell , 2001Arndt et al 2001;Tomlinson & Condie 2001;Condie 2001;Isley & Abbott 2002). Komatiites constitute at least 5% of the volcanic pile in about 60% of Archean greenstone belts (Figure 2 in de Wit & Ashwal 1997).…”

Section: High-mg Meltsmentioning

confidence: 99%

“…Building on earlier compilations [such as Coffin & Eldholm (1994) for young LIPs, Tomlinson & Condie (2001) for Archean LIPs, and Isley & Abbott (1999) for units older than 1.5 Ga], Ernst & Buchan (2001b compiled a LIP database and used it to assess the distribution of plume-head magmatic events in space and time back to 3.8 Ga. Three hundred and four possible LIP events were identified and divided into three classes ("well established," "probable," and "possible"). Thirty-one mafic magmatic events have been confidently related to mantle plume heads and are considered well established on the basis of the following criteria: emplacement of a large amount (areal coverage of >100,000 km 2 ) of magma in a short time (a few million years), the presence of a giant radiating dyke swarm, or a link to a present-day hot spot.…”

Section: Lip Record Through Timementioning

confidence: 99%

Recognizing Mantle Plumes in the Geological Record

Ernst

Buchan

2003

Annu. Rev. Earth Planet. Sci.

306

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Mantle plumes are recognized by domal uplift, triple junction rifting, and especially the presence of a large igneous province (LIP), dominated in the Phanerozoic by flood basalts, and in the Proterozoic by the exposed plumbing system of dykes, sills, and layered intrusions. In the Archean, greenstone belts that contain komatiites have been linked to plumes. In addition, some carbonatites and kimberlites may originate from plumes that have stalled beneath thick lithosphere. Geochemistry and isotopes can be used to test and characterize the plume origin of LIPs. Seismic tomography and geochemistry of crustal and subcrustal xenoliths in kimberlites can identify fossil plumes. More speculatively, plumes (or clusters of plumes) have been linked with variation in the isotopic composition of marine carbonates, sea-level rise, iron formations, anoxia events, extinctions, continental breakup, juvenile crust production, magnetic superchrons, and meteorite impacts. The central region of a plume is located using the focus of a radiating dyke swarm, the distribution of komatiites and picrites, etc. The outer boundary of a plume head circumscribes the main flood basalt distribution and approximately coincides with the edge of domal uplift that causes shoaling and offlap in regional sedimentation. 206 Pb/ 204 Pb, and low 143 Nd/ 144 Nd ratios. Its geochemical trends resemble continental crust. HIMU is characteristic of St. Helena, Austral-Cook Islands (Tubuai), Balleny Islands, and the Azores. HIMU represents strong enrichment of 206 Pb and 208 Pb relative to 204 Pb.

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“…Changes in eustatic sea level do not suffi ce to explain this observation because they have amplitudes of ~200 m in the Phanerozoic (Müller et al, 2008) and of <1 km over Earth's history (Flament et al, 2008). In this paper we focus on intraplate subaqueous Archean fl ood basalts that erupted away from continental rifting (Arndt, 1999;Tomlinson and Condie, 2001; Table 1); this allows us to characterize gravity-driven subsidence. Our generic thermo-mechanical numerical experiments suggest that synemplacement to postemplacement lateral ductile fl ow of hot lower crust could have maintained Archean CFBs close to sea level.…”

Section: Introductionmentioning

confidence: 99%

Lower crustal flow kept Archean continental flood basalts at sea level

Flament¹,

Rey²,

Coltice³

et al. 2011

Geology

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International audienceLarge basaltic provinces as much as 15 km thick are common in Archean cratons. Many of these flood basalts erupted through continental crust but remained at sea level. Although common in the Archean record, subaqueous continental flood basalts (CFBs) are rare to absent in the post-Archean. Here we show that gravity-driven lower crustal flow may have contributed to maintaining Archean CFBs close to sea level. Our numerical experiments reveal that the characteristic time to remove the thickness anomaly associated with a CFB decreases with increasing Moho temperature (T(M)), from 500 m.y. for T(M) approximate to 320 degrees C to 1 m.y. for T(M) approximate to 900 degrees C. This strong dependency offers the opportunity to assess, from the subsidence history of CFBs, whether continental geotherms were significantly hotter in the Archean. In particular, we show that the subsidence history of the ca. 2.7 Ga upper Fortescue Group in the East Pilbara Craton, Western Australia, requires Moho temperatures >>700 degrees C. Applied to eight other unambiguous subaqueous Archean CFBs, our results indicate Moho temperatures >>650 degrees C at the time of eruption. We suggest that the decrease in the relative abundance of subaqueous CFBs over Earth's history could reflect the secular cooling of the continental lithosphere due to the decrease in radiogenic heat production

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Archean mantle plumes: Evidence from greenstone belt geochemistry

Cited by 42 publications

References 0 publications

Review: secular tectonic evolution of Archean continental crust: interplay between horizontal and vertical processes in the formation of the Pilbara Craton, Australia

Review: secular tectonic evolution of Archean continental crust: interplay between horizontal and vertical processes in the formation of the Pilbara Craton, Australia

Recognizing Mantle Plumes in the Geological Record

Lower crustal flow kept Archean continental flood basalts at sea level

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