Torngat ultramafic lamprophyres and their relation to the North Atlantic Alkaline Province

Tappe, Sebastian; Jenner, George A.; Foley, Stephen F.; Heaman, Larry M.; Besserer, Dean; Kjarsgaard, Bruce A.; Ryan, Bruce D.

doi:10.1016/j.lithos.2004.03.040

Cited by 105 publications

(57 citation statements)

References 36 publications

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“…Digonnet et al (2000) reported a 40 Ar/ 39 Ar phlogopite age of 550 ± 15 Ma (2r) for an aillikite dyke from Abloviak Fjord in the Torngat Mountains of northern Quebec. Tappe et al (2004) demonstrated the extension of this UML swarm into Labrador to the southeast and emphasized the compositional diversity. The aillikite/carbonatite and mela-aillikite dyke varieties recognized in the Abloviak Fjord region were collectively referred to as 'Torngat UML' by Tappe et al (2004), who determined an U-Pb perovskite emplacement age of 584.0 ± 3.6 Ma (2r) for aillikite dyke Q39.…”

Section: North Atlantic Craton Torngat Mountains and Diamondiferousmentioning

confidence: 82%

“…Tappe et al (2004) demonstrated the extension of this UML swarm into Labrador to the southeast and emphasized the compositional diversity. The aillikite/carbonatite and mela-aillikite dyke varieties recognized in the Abloviak Fjord region were collectively referred to as 'Torngat UML' by Tappe et al (2004), who determined an U-Pb perovskite emplacement age of 584.0 ± 3.6 Ma (2r) for aillikite dyke Q39. These dykes intruded an area that is at least 1500 km 2 in size and, thus, form one of the largest known UML swarms.…”

Section: North Atlantic Craton Torngat Mountains and Diamondiferousmentioning

confidence: 82%

“…Green and Falloon, 1998), a volatile species not essential in the genesis of lamproites (Foley et al, 1986). Previously, CO 2 degassing during UML magma emplacement was suggested as a possible explanation for the Torngat aillikite/carbonatite and mela-aillikite compositional continuum (Tappe et al, 2004).…”

Section: Introductionmentioning

confidence: 96%

“…In this paper we present the case for the concurrent melting of two such contrasting metasomatic assemblages that had been introduced into the North Atlantic craton (NAC) mantle lithosphere at different times. The outcome was a suite of carbonate-potassic silicate magmas, the Torngat ultramafic lamprophyres, which form a diamondiferous dyke swarm across northern Labrador and easternmost Quebec, Canada (Tappe et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…Aillikite compositionally grades into carbonate-poor (to carbonate-free) varieties, for which we introduced the term mela-aillikite (Tappe et al, 2004(Tappe et al, , 2005. Although we previously noted these mela-aillikites can have mineralogical similarities to olivine lamproites, i.e., the occurrence of olivine and phlogopite phenocrysts with groundmass high-Ti potassian richterite, they differ from olivine lamproites in being significantly SiO 2 -undersaturated (30-37 wt% as opposed to 41-46 wt% SiO 2 for typical olivine lamproites; Mitchell and Bergman, 1991;Foley, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Between carbonatite and lamproite—Diamondiferous Torngat ultramafic lamprophyres formed by carbonate-fluxed melting of cratonic MARID-type metasomes

Tappe

Foley

Kjarsgaard

et al. 2008

Geochimica et Cosmochimica Acta

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256

104

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New U-Pb perovskite ages reveal that diamondiferous ultramafic lamprophyre magmas erupted through the Archean crust of northern Labrador and Quebec (eastern Canada) .2). These contrasting isotopic characteristics of aillikites/carbonatites and mela-aillikites, along with subtle differences in their modal carbonate, SiO 2 , Al 2 O 3 , Na 2 O, Cs-Rb, and Zr-Hf contents, are consistent with two distinctive metasomatic assemblages of different age in the mantle magma source region.Integration of petrologic, geochemical, and isotopic information leads us to propose that the isotopically enriched component originated from a reduced phlogopite-richterite-Ti-oxide dominated source assemblage that is reminiscent of MARID suite xenoliths. In contrast, the isotopically depleted component was derived from a more oxidized phlogopite-carbonate dominated source assemblage. We argue that low-degree CO 2 -rich potassic silicate melts from the convective upper mantle were preferentially channelled into an older, pre-existing MARID-type vein network at the base of the North Atlantic craton lithosphere, where they froze to form new phlogopite-carbonate dominated veins. Continued stretching and thinning of the cratonic lithosphere during the Late Neoproterozoic remobilized the carbonate-rich vein material and induced volatile-fluxed fusion of the MARID-type veins and the cold peridotite substrate. Isotopic modelling suggests that only 5-12% trace element contribution from such geochemically extreme MARID-type material is required to produce the observed compositional shift from the isotopically most depleted aillikites/carbonatites towards enriched mela-aillikites.We conclude that cold cratonic mantle lithosphere can host several generations of contrasting vein assemblages, and that each may have formed during past tectonic and magmatic events under distinctively different physicochemical conditions. Although cratonic MARID-type and carbonate-bearing veins in peridotite can be the respective sources for lamproite and carbonatite magmas when present as the sole metasome, their concomitant fusion in a complex source region may give rise to a whole new variety of deep volatile-rich magmas and we suggest that orangeites (formerly Group 2 kimberlites), kamafugites, and certain types of ultramafic lamprophyre are formed in this manner.

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Section: North Atlantic Craton Torngat Mountains and Diamondiferousmentioning

confidence: 82%

Section: North Atlantic Craton Torngat Mountains and Diamondiferousmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Between carbonatite and lamproite—Diamondiferous Torngat ultramafic lamprophyres formed by carbonate-fluxed melting of cratonic MARID-type metasomes

Tappe

Foley

Kjarsgaard

et al. 2008

Geochimica et Cosmochimica Acta

Self Cite

256

104

View full text Add to dashboard Cite

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Discovery of Mesoproterozoic kimberlite from Dörbed Banner, Inner Mongolia and its tectonic significance

Zhou

Wang

et al. 2017

Geological Journal

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Porphyritic olivine kimberlitic breccia, discovered in the Dörbed Banner of Inner Mongolia, Western China, is referred to as Longtou Shan Kimberlite in our study. This kimberlite occurs as a pipe in the Halahuogete Formation of Bayan Obo Group. Zircon U–Pb ages of Longtou Shan Kimberlite reveals a Mesoproterozoic age of ~1,552 Ma, constraining the deposition age of Halahuogete Formation to the Mesoproterozoic. Compared with Mesoproterozoic kimberlite of the ancient landmass, it can be inferred that the North China Craton is a member of the Ur ancient continent of the Columbia supercontinent. Furthermore, according to the tectonic background of the Bayan Obo Group, we raise this possibility that “Bayan Obo Aulacogen” should be renamed the “Bayan Obo Continental Rift.”

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Lithosphere–asthenosphere interaction and carbonatite metasomatism in the genesis of Mesoproterozoic shoshonitic lamprophyres at Korakkodu, Wajrakarur kimberlite field, Eastern Dharwar Craton, southern India

et al. 2019

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The spatial and temporal association between lamprophyres and kimberlites provides unique opportunities to explore their genetic relationships. This paper explores such a relationship by detailing mineralogical and geochemical aspects of Korakkodu lamprophyre dykes located within the well‐known Mesoproterozoic diamondiferous Wajrakarur Kimberlite field (WKF), towards the south‐western margin of Paleo–Mesoproterozoic Cuddapah Basin, Eastern Dharwar Craton, southern India. Mineralogy reveals that these dykes belong to calc‐alkaline variety of lamprophyres, but their geochemistry display mixed signals of both alkaline and calc‐alkaline lamprophyres. These lamprophyres are highly potassic, and their high Al2O3 and low‐TiO2 content implies a shoshonitic character. Low Mg#, Ni, and Cr concentration highlight their evolved nature. High (La/Yb)N and (Gd/Yb)N content is consistent with their derivation from low degrees of partial melting, whereas highly fractionated nature suggests the presence of garnet in their source. Absence of prominent Nb‐Ta anomaly implies to the dilution of lithospheric mantle source by melts rich in HFSEs and low La/Nb ratio compared to those of the calc‐alkaline island arc volcanics and suggests an asthenospheric overprint on lithospheric mantle source. Carbonatite metasomatism in the source region of these lamprophyres is apparent from conspicuously high‐Zr/Hf ratio, and the HFSE budget of these lamprophyres are principally controlled by the presence of phlogopite veins in their lithospheric source. An extremely heterogeneous and layered lithospheric mantle beneath Eastern Dharwar Craton has been inferred from the divergent genetic history of Mesoproterozoic lamprophyres and kimberlites in the Wajrakarur field.

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Torngat ultramafic lamprophyres and their relation to the North Atlantic Alkaline Province

Cited by 105 publications

References 36 publications

Between carbonatite and lamproite—Diamondiferous Torngat ultramafic lamprophyres formed by carbonate-fluxed melting of cratonic MARID-type metasomes

Between carbonatite and lamproite—Diamondiferous Torngat ultramafic lamprophyres formed by carbonate-fluxed melting of cratonic MARID-type metasomes

Discovery of Mesoproterozoic kimberlite from Dörbed Banner, Inner Mongolia and its tectonic significance

Lithosphere–asthenosphere interaction and carbonatite metasomatism in the genesis of Mesoproterozoic shoshonitic lamprophyres at Korakkodu, Wajrakarur kimberlite field, Eastern Dharwar Craton, southern India

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