Hafnium-Neodymium isotope, trace element and U-Pb zircon age constraints on the petrogenesis of the 3.44–3.46 Ga Dwalile greenstone remnant, Ancient gneiss Complex, Swaziland
Hoffmann JE, Musese E, Kröner A, Schneider K, Wong J, Hofmann A, Hegner E, Kasper HU, Tusch J, Münker C (2020)
Publication Type: Journal article
Publication year: 2020
Journal
Book Volume: 351
Article Number: 105970
DOI: 10.1016/j.precamres.2020.105970
Abstract
The geodynamic setting of the 3.44–3.46 Ga Dwalile greenstone remnant (DGR) of the Ancient Gneiss Complex (Swaziland) and its relationship to other Greenstone belts of similar age is investigated in this contribution. We present Hf-Nd isotope, major and trace element data for komatiites, komatiitic basalts, basalts, basaltic andesites as well as felsic volcanic and sedimentary rocks, all metamorphosed at amphibolite-facies grade. Major and trace element compositions of metabasalts and metakomatiites indicate crustal contamination. The best-preserved samples yield 176Lu-176Hf and 147Sm-143Nd isochron ages of ca. 3500 and 3460 Ma, respectively, in line with U-Pb zircon ages of interlayered felsic volcanic rocks of 3460 Ma. Isotope and trace element data for the metasedimentary rocks reveal a contribution of older crustal material with 3.53 Ga zircon grains. Together with >3.7 Ga inherited zircon grains in the Ngwane gneiss (NG) of the basement, this evidence supports a model of deposition of the Dwalile supracrustal rocks on or near older continental crust. Initial εHf and εNd values of the least contaminated DGR metabasalts and metakomatiites are similar to those of the contemporaneous Komati Formation komatiites and tholeiitic basalts, however, the trace element composition and slight correlations of initial εHf and εNd values with major and trace element parameters indicative for crustal contamination reveal differences in the basement of both units.
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Involved external institutions
Universität zu Köln
Germany (DE)
Freie Universität Berlin
Germany (DE)
University of Hong Kong (HKU) / 香港大學
Hong Kong (HK)
University of Johannesburg
South Africa (ZA)
Chinese Academy of Geological Sciences (CAGS) / 中国地质科学院
China (CN)
Ludwig-Maximilians-Universität (LMU)
Germany (DE)
Germany (DE)
Freie Universität Berlin
Germany (DE)
University of Hong Kong (HKU) / 香港大學
Hong Kong (HK)
University of Johannesburg
South Africa (ZA)
Chinese Academy of Geological Sciences (CAGS) / 中国地质科学院
China (CN)
Ludwig-Maximilians-Universität (LMU)
Germany (DE)
How to cite
APA:
Hoffmann, J.E., Musese, E., Kröner, A., Schneider, K., Wong, J., Hofmann, A.,... Münker, C. (2020). Hafnium-Neodymium isotope, trace element and U-Pb zircon age constraints on the petrogenesis of the 3.44–3.46 Ga Dwalile greenstone remnant, Ancient gneiss Complex, Swaziland. Precambrian Research, 351. https://dx.doi.org/10.1016/j.precamres.2020.105970
MLA:
Hoffmann, J. Elis, et al. "Hafnium-Neodymium isotope, trace element and U-Pb zircon age constraints on the petrogenesis of the 3.44–3.46 Ga Dwalile greenstone remnant, Ancient gneiss Complex, Swaziland." Precambrian Research 351 (2020).
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