Highly refractory Archaean peridotite cumulates: Petrology and geochemistry of the Seqi Ultramafic Complex, SW Greenland
Journal article
Authors | Szilas, Kristoffer, van Hinsberg, Vincent J., McDonald, Iain, Næraa, Tomas, Rollinson, Hugh, Adetunji, Jacob and Bird, Dennis |
---|---|
Abstract | This paper investigates the petrogenesis of the Seqi Ultramafic Complex, which covers a total area of approximately 0.5 km2. The ultramafic rocks are hosted by tonalitic orthogneiss of the ca. 3000 Ma Akia terrane with crosscutting granitoid sheets providing an absolute minimum age of 2978 ± 8 Ma for the Seqi Ultramafic Complex. The Seqi rocks represent a broad range of olivine-dominated plutonic rocks with varying modal amounts of chromite, orthopyroxene and amphibole, i.e. various types of dunite (s.s.), peridotite (s.l.), as well as chromitite. The Seqi Ultramafic Complex is characterised primarily by refractory dunite, with highly forsteritic olivine with core compositions having Mg# ranging from about 91 to 93. The overall high modal contents, as well as the specific compositions, of chromite rule out that these rocks represent a fragment of Earth’s mantle. The occurrence of stratiform chromitite bands in peridotite, thin chromite layers in dunite and poikilitic orthopyroxene in peridotite instead supports the interpretation that the Seqi Ultramafic Complex represents the remnant of a fragmented layered complex or a magma conduit, which was subsequently broken up and entrained during the formation of the regional continental crust. Integrating all of the characteristics of the Seqi Ultramafic Complex points to formation of these highly refractory peridotites from an extremely magnesian (Mg# ~ 80), near-anhydrous magma, as olivine-dominated cumulates with high modal contents of chromite. It is noted that the Seqi cumulates were derived from a mantle source by extreme degrees of partial melting (>40%). This mantle source could potentially represent the precursor for the sub-continental lithospheric mantle (SCLM) in this region, which has previously been shown to be ultra-depleted. The Seqi Ultramafic Complex, as well as similar peridotite bodies in the Fiskefjord region, may thus constitute the earliest cumulates that formed during the large-scale melting event(s), which resulted in the ultra depleted cratonic keel under the North Atlantic Craton. Hence, a better understanding of such Archaean ultramafic complexes may provide constraints on the geodynamic setting of Earth’s first continents and the corresponding SCLM. |
Keywords | Archaean; Ultramafic; North Atlantic craton; Dunite; Platinum-group elements; Ultra-depleted mantle; Fiskefjord |
Year | 2017 |
Journal | Geoscience Frontiers |
Journal citation | 9 (3), pp. 1-26 |
Publisher | Elsevier |
ISSN | 1674-9871 |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.gsf.2017.05.003 |
Web address (URL) | https://www.sciencedirect.com/science/article/pii/S1674987117300993?via%3Dihub |
hdl:10545/621658 | |
Output status | Published |
Publication dates | 06 Jun 2017 |
Publication process dates | |
Deposited | 21 Jun 2017, 15:42 |
Accepted | 21 May 2017 |
Rights | Archived with thanks to Geoscience Frontiers |
Contributors | Stanford University, McGill University, Lund University, Cardiff University and University of Derby |
File | License File Access Level Open |
File | File Access Level Restricted |
https://repository.derby.ac.uk/item/9272w/highly-refractory-archaean-peridotite-cumulates-petrology-and-geochemistry-of-the-seqi-ultramafic-complex-sw-greenland
Download files
51
total views44
total downloads1
views this month7
downloads this month
Export as
Related outputs
The significance of water in the genesis of ophiolitic chromitites
Rollinson, H. 2025. The significance of water in the genesis of ophiolitic chromitites. Lithos. 502–503. https://doi.org/10.1016/j.lithos.2025.108022Do all Archaean TTG rock compositions represent former melts
Rollinson, H. 2025. Do all Archaean TTG rock compositions represent former melts. Precambrian Research. 367, pp. 1-13. https://doi.org/10.1016/j.precamres.2021.106448Zircon trace element geochemistry of the neoarchaean late-granite suites along the southern margin of the Zimbabwe craton, Zimbabwe
Chagondah, G. S., Elburg, M. A., Hofmann, A., Rollinson, H., Ueckermann, H. and Vorster, C. 2025. Zircon trace element geochemistry of the neoarchaean late-granite suites along the southern margin of the Zimbabwe craton, Zimbabwe. Journal of African Earth Sciences. 228, pp. 1-13. https://doi.org/10.1016/j.jafrearsci.2025.105619Neoarchaean and Palaeoproterozoic tectono-metamorphic events along the southern margin of the Zimbabwe craton: Insights from muscovite 40Ar/39Ar geochronology from rare-metal pegmatites, Zimbabwe
Chagondah, G. S., Kramers, J. D., Hofmann, A. and Rollinson, H. 2024. Neoarchaean and Palaeoproterozoic tectono-metamorphic events along the southern margin of the Zimbabwe craton: Insights from muscovite 40Ar/39Ar geochronology from rare-metal pegmatites, Zimbabwe. Journal of African Earth Sciences . 217, pp. 1-12.Magma mingling in plagiogranites of the Oman ophiolite suggests an origin by fractional crystallisation
Rollinson, H. 2024. Magma mingling in plagiogranites of the Oman ophiolite suggests an origin by fractional crystallisation. Lithos. 482-483, pp. 1-12. https://doi.org/10.1016/j.lithos.2024.107725The late Archaean granite paradox: A case study from the Zimbabwe Craton
Rollinson, H., Chagondah, G. and Hofmann, A. 2024. The late Archaean granite paradox: A case study from the Zimbabwe Craton. Precambrian Research. 410, pp. 1-11. https://doi.org/10.1016/j.precamres.2024.107491The late Archaean granite paradox
Rollinson, H., Chagondah, G. S. and Hofmann, A., 2023. The late Archaean granite paradox. Goldschmidt 2023. https://doi.org/10.7185/gold2023.16638Ferric iron in chrome-bearing spinels: implications for microprobe correction procedures
Rollinson, H. and Adetunji, J. 2023. Ferric iron in chrome-bearing spinels: implications for microprobe correction procedures. Mineralogical Magazine. 87 (5), pp. 702-710. https://doi.org/10.1180/mgm.2023.68The growth of the Zimbabwe craton during the Neoarchaean
Rollinson, H. 2023. The growth of the Zimbabwe craton during the Neoarchaean. Contributions to Mineralogy and Petrology. 178, pp. 1-16. https://doi.org/10.1007/s00410-022-01978-7The rare earth element geochemistry of mafic granulites from the Neoarchaean northern marginal zone of the Limpopo Belt
Rollinson, H. 2022. The rare earth element geochemistry of mafic granulites from the Neoarchaean northern marginal zone of the Limpopo Belt. Journal of African Earth Sciences. 186, pp. 1-12. https://doi.org/10.1016/j.jafrearsci.2021.104434The origin of the Earth’s continental crust
Rollinson, H. 2021. The origin of the Earth’s continental crust. Teaching Earth Sciences. 46, pp. 38-43.No plate tectonics necessary to explain Eoarchean rocks at Isua (Greenland)
Rollinson, H. 2021. No plate tectonics necessary to explain Eoarchean rocks at Isua (Greenland). Geology. 50 (2), p. 147–151. https://doi.org/10.1130/G49278.1Ethical challenges for mineral resource extraction in Sierra Leone
Rollinson, H. 2020. Ethical challenges for mineral resource extraction in Sierra Leone. The EGU General Assembly 2020. European Geosciences Union. https://doi.org/10.5194/egusphere-egu2020-2636Dunites in the mantle section of the Oman ophiolite – The boninite connection
Rollinson, H. 2019. Dunites in the mantle section of the Oman ophiolite – The boninite connection. Lithos. 334–335, pp. 1-7. https://doi.org/10.1016/j.lithos.2019.03.008Ethical challenges in mineral resource extraction: a case study from Sierra Leone
Rollinson, H. 2019. Ethical challenges in mineral resource extraction: a case study from Sierra Leone. Geoscience and Society Summit, Stockholm. American Geophysical Union (AGU).The eastern French Pyrenees: from mountain belt to foreland basin
Satterfield, Dorothy, Rollinson, H. and Suthren, Roger 2019. The eastern French Pyrenees: from mountain belt to foreland basin. Geology Today. 35 (6), pp. 228-240. https://doi.org/10.1111/gto.12291Polymineralic inclusions in mantle chromitites from the Oman ophiolite indicate a highly magnesian parental melt
Rollinson, H., Mameri, L. and Barry, T. 2018. Polymineralic inclusions in mantle chromitites from the Oman ophiolite indicate a highly magnesian parental melt. Lithos. 310–311, pp. 381-391. https://doi.org/10.1016/j.lithos.2018.04.024
Trevorite: Ni-rich spinel formed by metasomatism and desulfurization processes at Bon Accord, South Africa?
O'Driscoll, Brian, Clay, Patricia L., Cawthorn, R. Grant, Lenaz, Davide, Adetunji, Jacob and Kronz, Andreas 2014. Trevorite: Ni-rich spinel formed by metasomatism and desulfurization processes at Bon Accord, South Africa? Mineralogical Magazine. https://doi.org/10.1180/minmag.2014.078.1.11
UK pension changes in 2015: some mathematical considerations
Stubbs, John and Adetunji, Jacob 2016. UK pension changes in 2015: some mathematical considerations. The Mathematical Gazette. https://doi.org/10.1017/mag.2016.55Explainer: what dust from the Sahara does to you and the planet
Adetunji, Jacob 2016. Explainer: what dust from the Sahara does to you and the planet. The Conversation.
Low temperature, authigenic illite and carbonates in a mixed dolomite-clastic lagoonal and pedogenic setting, Spanish Central System, Spain
Huggett, Jennifer, Cuadros, Javier, Gale, Andrew S., Wray, David and Adetunji, Jacob 2016. Low temperature, authigenic illite and carbonates in a mixed dolomite-clastic lagoonal and pedogenic setting, Spanish Central System, Spain. Applied Clay Science. https://doi.org/10.1016/j.clay.2016.06.016
57Fe Mössbauer spectroscopy investigations of iron oxidation states in the Harmattan dust nutrient contribution to West African soils
Adetunji, Jacob 2014. 57Fe Mössbauer spectroscopy investigations of iron oxidation states in the Harmattan dust nutrient contribution to West African soils. Atmospheric Environment. https://doi.org/10.1016/j.atmosenv.2014.09.025