Tusch, Jonas ORCID: 0000-0001-7492-8037, Muenker, Carsten, Hasenstab, Eric ORCID: 0000-0002-7688-6659, Jansen, Mike, Marien, Chris S., Kurzweil, Florian ORCID: 0000-0002-8202-1475, Van Kranendonk, Martin J., Smithies, Hugh, Maier, Wolfgang and Garbe-Schoenberg, Dieter (2021). Convective isolation of Hadean mantle reservoirs through Archean time. Proc. Natl. Acad. Sci. U. S. A., 118 (2). WASHINGTON: NATL ACAD SCIENCES. ISSN 0027-8424

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Abstract

Although Earth has a convecting mantle, ancient mantle reservoirs that formed within the first 100 Ma of Earth's history (Hadean Eon) appear to have been preserved through geologic time. Evidence for this is based on small anomalies of isotopes such as W-182, Nd-142, and Xe-129 that are decay products of short-lived nuclide systems. Studies of such short-lived isotopes have typically focused on geological units with a limited age range and therefore only provide snapshots of regional mantle heterogeneities. Here we present a dataset for short-lived Hf-182-W-182 (half-life 9 Ma) in a comprehensive rock suite from the Pilbara Craton, Western Australia. The samples analyzed preserve a unique geological archive covering 800 Ma of Archean history. Pristine W-182 signatures that directly reflect the W isotopic composition of parental sources are only preserved in unaltered mafic samples with near canonical W/Th (0.07 to 0.26). Early Paleoarchean, mafic igneous rocks from the East Pilbara Terrane display a uniform pristine mu W-182 excess of 12.6 +/- 1.4 ppm. From ca. 3.3Ga onward, the pristine W-182 signatures progressively vanish and are only preserved in younger rocks of the craton that tap stabilized ancient lithosphere. Given that the anomalous W-182 signature must have formed by ca. 4.5 Ga, the mantle domain that was tapped by magmatism in the Pilbara Craton must have been convectively isolated for nearly 1.2 Ga. This finding puts lower bounds on timescale estimates for localized convective homogenization in early Earth's interior and on the widespread emergence of plate tectonics that are both important input parameters in many physical models.

Item Type: Journal Article
Creators:
CreatorsEmailORCIDORCID Put Code
Tusch, JonasUNSPECIFIEDorcid.org/0000-0001-7492-8037UNSPECIFIED
Muenker, CarstenUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Hasenstab, EricUNSPECIFIEDorcid.org/0000-0002-7688-6659UNSPECIFIED
Jansen, MikeUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Marien, Chris S.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Kurzweil, FlorianUNSPECIFIEDorcid.org/0000-0002-8202-1475UNSPECIFIED
Van Kranendonk, Martin J.UNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Smithies, HughUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Maier, WolfgangUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
Garbe-Schoenberg, DieterUNSPECIFIEDUNSPECIFIEDUNSPECIFIED
URN: urn:nbn:de:hbz:38-589630
DOI: 10.1073/pnas.2012626118
Journal or Publication Title: Proc. Natl. Acad. Sci. U. S. A.
Volume: 118
Number: 2
Date: 2021
Publisher: NATL ACAD SCIENCES
Place of Publication: WASHINGTON
ISSN: 0027-8424
Language: English
Faculty: Unspecified
Divisions: Unspecified
Subjects: no entry
Uncontrolled Keywords:
KeywordsLanguage
SIDEROPHILE ELEMENT ABUNDANCES; TUNGSTEN ISOTOPIC EVIDENCE; CONTINENTAL-CRUST; PILBARA CRATON; SUPRACRUSTAL ROCKS; W-182; EARTH; GA; EVOLUTION; ND-142Multiple languages
Multidisciplinary SciencesMultiple languages
URI: http://kups.ub.uni-koeln.de/id/eprint/58963

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