Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths

Hughes, Hannah S.R.; McDonald, Iain; Goodenough, Kathryn; Ciborowski, T. Jake R.; Kerr, Andrew C.; Davies, Joshua; Selby, David

doi:10.1016/j.precamres.2014.05.026

Cited by 48 publications

(25 citation statements)

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“…Also presented are the whole-rock compositions for host dykes to the xenoliths. Note that results from Loch Roag marked with (*) have been reported previously in Hughes et al (2014). show polycrystalline clinopyroxenes surrounding and including fine granular olivine and chromite crystals (Fig.…”

Section: Petrography and Accessory Mineralogysupporting

confidence: 66%

“…formation of Laxfordian high-grade metamorphic belts; (5) continued calc-alkaline magmatism 1.8À1.7 Ga, including further deformation and prograde amphibolite-facies metamorphism and Laxfordian crustal anatexsis (Bridgwater et al, 1973;Park, 1994;Park, 1995;Kinny et al, 2005;Park, 2005;Hughes et al, 2014;Vernon et al, 2014).…”

Section: Overview Of the North Atlantic Craton à Formation Amalgamatmentioning

confidence: 99%

“…Previous studies on the spinel lherzolites were concerned with the isotopic composition and mineral chemistry of the major rock-forming minerals (see Upton et al, 2011 and references therein). New Re-Os whole-rock isotopic data for a Loch Roag spinel lherzolite are also available in Hughes et al (2014) (see Table 1). Overall, the spinel lherzolites are granoblastic, porphyroblastic to sub-equigranular with crystal sizes typically ranging from 200 mm to 1 mm in size.…”

Section: Loch Roag Isle Of Lewis (Hebridean Terrane)mentioning

confidence: 99%

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Trace-element abundances in the shallow lithospheric mantle of the North Atlantic Craton margin: Implications for melting and metasomatism beneath Northern Scotland

et al. 2015

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Bulk rock geochemistry and major-and trace-element compositions of clinopyroxene have been determined for three suites of peridotitic mantle xenoliths from the North Atlantic Craton (NAC) in northern Scotland, to establish the magmatic and metasomatic history of subcontinental lithospheric mantle (SCLM) below this region. Spinel lherzolites from the southernmost locality (Streap Com'laidh) have non-NAC mantle compositions, while the two northern xenolith suites (Loch Roag and Rinibar) are derived from the thinned NAC marginal keel. Clinopyroxene compositions have characteristic trace-element signatures which show both 'primary' and 'metasomatic' origins. We use Zr and Hf abundances to identify ancient cryptic refertilization in 'primary' clinopyroxenes. We suggest that Loch Roag and Rinibar peridotite xenoliths represent an ancient ArchaeanPalaeoproterozoic SCLM with original depleted cratonic signatures which were overprinted by metasomatism around the time of intrusion of the Scourie Dyke Swarm (~2.4 Ga). This SCLM keel was preserved during Caledonian orogenesis, although some addition of material and/or metasomatism probably also occurred, as recorded by Rinibar xenoliths. Rinibar and Streap xenoliths were entrained in Permo-Carboniferous magmas and thus were isolated from the SCLM~200 Ma before Loch Roag xenoliths (in an Eocene dyke). Crucially, despite their geographical location, lithospheric mantle peridotite samples from Loch Roag show no evidence of recent melting or refertilization during the Palaeogene opening of the Atlantic.

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Section: Petrography and Accessory Mineralogysupporting

confidence: 66%

Section: Overview Of the North Atlantic Craton à Formation Amalgamatmentioning

confidence: 99%

Section: Loch Roag Isle Of Lewis (Hebridean Terrane)mentioning

confidence: 99%

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Trace-element abundances in the shallow lithospheric mantle of the North Atlantic Craton margin: Implications for melting and metasomatism beneath Northern Scotland

et al. 2015

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“…To explain the high trace element contents, one could suggest that Kaapvaal xenoliths are non-representative of the Kaapvaal SCLM. A recent study on SCLM xenoliths from Scotland (Hughes et al 2014) indicates the existence of SCLM reservoirs that show relatively high PGE contents, yet strong negative Nb-Ta, Ti and Zr-Hf anomalies. These rocks were interpreted to reflect SCLM metasomatized by carbonatite melts, but their Nb levels are still too high to explain the composition of the NG2 chills.…”

Section: Magma Derivation From the Sclmmentioning

confidence: 99%

“…9 Primitive mantle-normalized multi-element patterns of a the NG2 chill samples compared to average B1 magma , the B1 chill sequence at Clapham (Wilson 2012), the quartzitic floor rock, DMM (Workman and Hart 2005), and upper continental crust (Rudnick and Fountain 1995). b Patterns for Kaapvaal peridotite mantle xenoliths and MARID, as well as xenoliths from Loch Roag, Scotland (Hughes et al 2014). Normalization factors from Sun and McDonough (1989) Page 13 of 22 57 whereas the Pt contents are markedly higher than in the global magmas (see also Barnes et al 2015).…”

Section: Chalcophile Elementsmentioning

confidence: 99%

A chilled margin of komatiite and Mg-rich basaltic andesite in the western Bushveld Complex, South Africa

Maier

Barnes

2016

Contrib Mineral Petrol

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Geochemistry, geochronology, and geodynamic implications of mafic‐felsic dykes from the Hadamengou area, north‐western North China Craton

Liu

Zhang

et al. 2020

Geological Journal

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Occurrences of multistage dykes provide a critical opportunity to constrain the nature of geological setting in the Daqingshan region during the Late Neoarchean to Middle Palaeoproterozoic. In this article, we present the results of zircon U-Pb ages and whole-rock geochemical data from mafic-felsic dykes in the Hadamengou area in order to constrain their ages and tectonic significance. Based on their zircon U-Pb ages, these dykes can be divided into four types: 2.52 Ga metadiabase, 2.45 Ga K-feldspar granite, 2.44 Ga granitic pegmatite, and 1.99 Ga metagabbro. Geochemically, the 2.52 Ga metadiabase rocks have low SiO 2 , high MgO, and Na 2 O/ K 2 O ratios, with enrichment in LILE and depletion in HFSE, which suggests these rocks originated from melting of the lithosphere mantle components metasomatised by subducted slab-derived fluids. The 2.45 Ga K-feldspar granite and the 2.44 Ga granitic pegmatite are characterised by high SiO 2 and Na 2 O + K 2 O contents, low MgO, Ni and Cr contents, and high A/CNK ratios, similar to typical features of strongly peraluminous granites. Additionally, these rocks show a variation of Eu anomalies and strong depletion of Th, U, Nb, and Ta elements, which characteristics are considered as a feature of anatectic origin. The 1.99 Ga metagabbro rocks belong to calc-alkaline rock series, and contain low SiO 2 contents, high MgO, Cr and Ni contents, negative Nb, Ta, and Ti anomalies, and high LILE abundances without Eu anomalies. Geological features of the metagabbro dykes indicate that they are likely derived from partial melting of the subduction-related metasomatised lithospheric mantle. Combined with the evidence of mafic-felsic dykes in the Hadamengou and magmatism in the adjacent area, a complex tectonic evolution history during Late Neoarchean to Middle Palaeoproterozoic is presented in the Daqingshan region, which is associated with the amalgamation of micro-blocks within the North China Craton (NCC), regional extension after cratonisation and subduction of the old ocean between the Yinshan Block and the Ordos Block.

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Enriched lithospheric mantle keel below the Scottish margin of the North Atlantic Craton: Evidence from the Palaeoproterozoic Scourie Dyke Swarm and mantle xenoliths

Cited by 48 publications

References 74 publications

Trace-element abundances in the shallow lithospheric mantle of the North Atlantic Craton margin: Implications for melting and metasomatism beneath Northern Scotland

Trace-element abundances in the shallow lithospheric mantle of the North Atlantic Craton margin: Implications for melting and metasomatism beneath Northern Scotland

A chilled margin of komatiite and Mg-rich basaltic andesite in the western Bushveld Complex, South Africa

Geochemistry, geochronology, and geodynamic implications of mafic‐felsic dykes from the Hadamengou area, north‐western North China Craton

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