Rare evidence for the existence of a Hadean enriched mantle reservoir
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Keywords: short-lived 146Sm-142Nd, enriched mantle, Hadean
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Abstract
Figures
 Figure 1 Simplified geological map of the Borborema Province. Tectonic domains; MCD – Médio coreau domain; CD – Ceará domain; RGND – Rio grande do norte domain; TD- transversal domain; SD – Southern domain. Archean cratons; AC- Amazon craton; SFC – São Francisco craton. See Figure S-1 for detailed geological map. |  Figure 2 μ142Nd for the Bom Jesus samples. Grey band shows external error on the standard. Dashed line shows the average μ142Nd = −10.2 for the amphibolite samples exhibiting μ142Nd outside of the JNdi-1 error. Errors on data points are 2σ. Duplicate samples are labelled. |  Figure 3 μ142Nd evolution of the source of the Bom Jesus amphibolites. Horizontal line at μ142Nd = 0 represents a reservoir with chondritic Sm/Nd and present day μ142Nd corresponding to modern mantle. Blue dashed line represents a super-chondritic BSE (Frossard et al., 2022; Johnston et al., 2022). Grey band as in Figure 2. Red and green envelopes represent modelled enriched and depleted reservoirs formed at 4470 Ma. Black dashed lines show these reservoirs formed at 4400 Ma and evolving to the same present day μ142Nd. Thin solid black lines correspond to the 147Sm/144Nd required to evolve to μ142Nd = −10 (average amphibolite value). Blue line shows a 4400 Ma reservoir derived from a super-chondritic BSE. The Bom Jesus samples are displaced around their interpreted age (3.4 Ga) for clarity. SW Greenland and NE Canada data are average μ142Nd values for distinct mantle-derived lithologies. Schapenburg komatiite, Dwalie Greenstone and Komati formation data show average values (Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021). Ameralik dike data shows the lowest μ142Nd value measured (Rizo et al., 2012). |  Figure 4 μ142Nd histograms for ≤3.4 Ga mantle-derived rocks. Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021). Nuvvuagittuq data in top panel are measured 142Nd compositions, while bottom panel shows the initial μ142Nd at 4.31 Ga if the rocks are considered Hadean (O’Neil et al., 2012). |
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Introduction
The formation of the Earth was associated with considerable thermal energy, leading to large scale differentiation shortly after its formation. It has been suggested that the Earth formed, at least in part, from already differentiated bodies (e.g., Kruijer et al., 2014
Kruijer, T.S., Touboul, M., Fischer-Gödde, M., Bermingham, K.R., Walker, R.J., Kleine, T. (2014) Protracted core formation and rapid accretion of protoplanets. Science 344, 1150–1154, https://doi.org/10.1126/science.1251766.
; Frossard et al., 2022Frossard, P., Israel, C., Bouvier, A., Boyet, M. (2022) Earth’s composition was modified by collisional erosion. Science 377, 1529–1532, https://doi.org/10.1126/science.abq7351.
). Giant impacts, such as the Moon-forming event, with ensuing magma ocean formation and crystallisation, also contributed to extensive differentiation of the early mantle. These differentiation processes were consequential on the composition of Earth’s various geochemical reservoirs (Carlson et al., 2015Carlson, R.W., Boyet, M., O’Neil, J., Rizo, H., Walker, R.J. (2015) Early Differentiation and its Long-Term Consequences for Earth Evolution. In: Badro, J., Walter, M. (Eds.) The Early Earth: Accretion and Differentiation, 143–172.
), but have been greatly obscured by more than four billion years of geological activity. High precision measurements of short lived isotopic systems can however provide insights into the early differentiation of the silicate Earth and growing evidence from systems such as 146Sm-142Nd, 182Hf-182W and 129I-129Xe, supports a complex differentiation history of the mantle during the first few tens to hundreds of million years of Earth’s evolution (Bennett et al., 2007Bennett, V.C., Brandon, A.D., Nutman, A.P. (2007) Coupled 142Nd-143Nd isotopic evidence for hadean mantle dynamics. Science 318, 1907–1910, https://doi.org/10.1126/science.1145928.
; Willbold et al., 2011Willbold, M., Elliott, T., Moorbath, S. (2011) The tungsten isotopic composition of the Earth’s mantle before the terminal bombardment. Nature 477, 195–198, https://doi.org/10.1038/nature10399.
; Tucker and Mukhopadhyay, 2014Tucker, J.M., Mukhopadhyay, S. (2014) Evidence for multiple magma ocean outgassing and atmospheric loss episodes from mantle noble gases. Earth and Planetary Science Letters 393, 254–265, https://doi.org/10.1016/j.epsl.2014.02.050.
).The short lived 146Sm-142Nd isotopic system is a powerful tool to understand the early differentiation of the silicate Earth. Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where
, have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006Caro, G., Bourdon, B., Birck, J.L., Moorbath, S. (2006) High-precision 142Nd/144Nd measurements in terrestrial rocks: Constraints on the early differentiation of the Earth’s mantle. Geochimica et Cosmochimica Acta 70, 164–191, https://doi.org/10.1016/j.gca.2005.08.015.
; Bennett et al., 2007Bennett, V.C., Brandon, A.D., Nutman, A.P. (2007) Coupled 142Nd-143Nd isotopic evidence for hadean mantle dynamics. Science 318, 1907–1910, https://doi.org/10.1126/science.1145928.
; Rizo et al., 2011Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M. (2011) Combined Nd and Hf isotope evidence for deep-seated source of Isua lavas. Earth and Planetary Science Letters 312, 267–279, https://doi.org/10.1016/j.epsl.2011.10.014.
; Li et al., 2017Li, C.F., Wang, X.C., Wilde, S.A., Li, X.H., Wang, Y.F., Li, Z. (2017) Differentiation of the early silicate Earth as recorded by 142Nd-143Nd in 3.8–3.0 Ga rocks from the Anshan Complex, North China Craton. Precambrian Research 301, 86–101, https://doi.org/10.1016/j.precamres.2017.09.001.
; Morino et al., 2017Morino, P., Caro, G., Reisberg, L., Schumacher, A. (2017) Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm–142,143Nd systematics in ultramafic rocks of the Saglek block (3.25–3.9 Ga; northern Labrador, Canada). Earth and Planetary Science Letters 463, 136–150, https://doi.org/10.1016/j.epsl.2017.01.044.
), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006Caro, G., Bourdon, B., Birck, J.L., Moorbath, S. (2006) High-precision 142Nd/144Nd measurements in terrestrial rocks: Constraints on the early differentiation of the Earth’s mantle. Geochimica et Cosmochimica Acta 70, 164–191, https://doi.org/10.1016/j.gca.2005.08.015.
; Rizo et al., 2011Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M. (2011) Combined Nd and Hf isotope evidence for deep-seated source of Isua lavas. Earth and Planetary Science Letters 312, 267–279, https://doi.org/10.1016/j.epsl.2011.10.014.
; Morino et al., 2017Morino, P., Caro, G., Reisberg, L., Schumacher, A. (2017) Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm–142,143Nd systematics in ultramafic rocks of the Saglek block (3.25–3.9 Ga; northern Labrador, Canada). Earth and Planetary Science Letters 463, 136–150, https://doi.org/10.1016/j.epsl.2017.01.044.
; Hasenstab-Dübeler et al., 2022Hasenstab-Dübeler, E., Tusch, J., Hoffmann, J.E., Fischer-Gödde, M., Szilas, K., Münker, C. (2022) Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements. Chemical Geology 614, 121141, https://doi.org/10.1016/j.chemgeo.2022.121141.
). Such a differentiation event should have produced a complementary enriched reservoir, but evidence for its existence is more tenuous. Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008O’Neil, J., Carlson, R.W., Francis, D., Stevenson, R.K. (2008) Neodymium-142 evidence for hadean mafic crust. Science 321, 1828–1831, https://doi.org/10.1126/science.1161925.
; Caro et al., 2017Caro, G., Morino, P., Mojzsis, S.J., Cates, N.L., Bleeker, W. (2017) Sluggish Hadean geodynamics: Evidence from coupled 146,147Sm–142,143Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec). Earth and Planetary Science Letters 457, 23–37, https://doi.org/10.1016/j.epsl.2016.09.051.
; O’Neil and Carlson, 2017O’Neil, J., Carlson, R.W. (2017) Building Archean cratons from Hadean mafic crust. Science 355, 1199–1202, https://doi.org/10.1126/science.aah3823.
; Reimink et al., 2018Reimink, J.R., Chacko, T., Carlson, R.W., Shirey, S.B., Liu, J., Stern, R.A., Bauer, A.M., Pearson, D.G., Heaman, L.M. (2018) Petrogenesis and tectonics of the Acasta Gneiss Complex derived from integrated petrology and 142Nd and 182W extinct nuclide-geochemistry. Earth and Planetary Science Letters 494, 12–22, https://doi.org/10.1016/j.epsl.2018.04.047.
; Guitreau et al., 2019Guitreau, M., Boyet, M., Paquette, J.-L., Gannoun, A., Konc, Z., Benbakkar, M., Suchorski, K., Hénot, J.-M. (2019) Hadean protocrust reworking at the origin of the Archean Napier Complex (Antarctica). Geochemical Perspectives Letters 12, 7–11, https://doi.org/10.7185/geochemlet.1927.
; Wang et al., 2023Wang, D., Qiu, X.-F., Carlson, R.W. (2023) The Eoarchean Muzidian gneiss complex: Long-lived Hadean crustal components in the building of Archean continents. Earth and Planetary Science Letters 605, 118037, https://doi.org/10.1016/j.epsl.2023.118037.
), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle. Only sparse Palaeoarchean (3.6 to 3.2 Ga) mantle-derived rocks hint at an early enriched mantle source, with few resolved negative μ142Nd anomalies (Rizo et al., 2012Rizo, H., Boyet, M., Blichert-Toft, J., O’Neil, J., Rosing, M.T., Paquette, J.L. (2012) The elusive Hadean enriched reservoir revealed by 142Nd deficits in Isua Archaean rocks. Nature 491, 96–100, https://doi.org/10.1038/nature11565.
; Puchtel et al., 2016Puchtel, I.S., Blichert-Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182 W- 142 Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193, https://doi.org/10.1002/2016GC006324.
; Schneider et al., 2018Schneider, K.P., Hoffmann, J.E., Boyet, M., Münker, C., Kröner, A. (2018) Coexistence of enriched and modern-like 142Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa. Earth and Planetary Science Letters 487, 54–66, https://doi.org/10.1016/j.epsl.2018.01.022.
; Boyet et al., 2021Boyet, M., Garçon, M., Arndt, N., Carlson, R.W., Konc, Z. (2021) Residual liquid from deep magma ocean crystallization in the source of komatiites from the ICDP drill core in the Barberton Greenstone Belt. Geochimica et Cosmochimica Acta 304, 141–159, https://doi.org/10.1016/j.gca.2021.04.020.
), whose existence remains unclear.Here we present 142Nd data obtained on ≥3.4 Ga mafic amphibolite xenoliths from the São José do Campestre Massif, NE Brazil, which are the first results reporting 142Nd anomalies in rocks from South America. More importantly, our results provide clear evidence for the existence of a Hadean enriched mantle, potentially complementary to the early depleted reservoir recorded by the Eoarchean mantle-derived rocks from the North Atlantic and North China cratons (Caro et al., 2006
Caro, G., Bourdon, B., Birck, J.L., Moorbath, S. (2006) High-precision 142Nd/144Nd measurements in terrestrial rocks: Constraints on the early differentiation of the Earth’s mantle. Geochimica et Cosmochimica Acta 70, 164–191, https://doi.org/10.1016/j.gca.2005.08.015.
; Bennett et al., 2007Bennett, V.C., Brandon, A.D., Nutman, A.P. (2007) Coupled 142Nd-143Nd isotopic evidence for hadean mantle dynamics. Science 318, 1907–1910, https://doi.org/10.1126/science.1145928.
; Rizo et al., 2011Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M. (2011) Combined Nd and Hf isotope evidence for deep-seated source of Isua lavas. Earth and Planetary Science Letters 312, 267–279, https://doi.org/10.1016/j.epsl.2011.10.014.
; Li et al., 2017Li, C.F., Wang, X.C., Wilde, S.A., Li, X.H., Wang, Y.F., Li, Z. (2017) Differentiation of the early silicate Earth as recorded by 142Nd-143Nd in 3.8–3.0 Ga rocks from the Anshan Complex, North China Craton. Precambrian Research 301, 86–101, https://doi.org/10.1016/j.precamres.2017.09.001.
; Morino et al., 2017Morino, P., Caro, G., Reisberg, L., Schumacher, A. (2017) Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm–142,143Nd systematics in ultramafic rocks of the Saglek block (3.25–3.9 Ga; northern Labrador, Canada). Earth and Planetary Science Letters 463, 136–150, https://doi.org/10.1016/j.epsl.2017.01.044.
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Results
The São José do Campestre Massif is an Archean basement inlier occurring within the Neoproterozoic Borborema Province of NE Brazil (Dantas et al., 2013
Dantas, E.L., De Souza, Z.S., Wernick, E., Hackspacher, P.C., Martin, H., Xiaodong, D., Li, J.W. (2013) Crustal growth in the 3.4-2.7Ga São José de Campestre Massif, Borborema Province, NE Brazil. Precambrian Research 227, 120–156, https://doi.org/10.1016/j.precamres.2012.08.006.
) (Fig. 1). It includes gneisses from the tonalite-trondhjemite-granodiorite (TTG) series and supracrustal sequences, with ages from 3.4 to 2.7 Ga (Dantas et al., 2013Dantas, E.L., De Souza, Z.S., Wernick, E., Hackspacher, P.C., Martin, H., Xiaodong, D., Li, J.W. (2013) Crustal growth in the 3.4-2.7Ga São José de Campestre Massif, Borborema Province, NE Brazil. Precambrian Research 227, 120–156, https://doi.org/10.1016/j.precamres.2012.08.006.
). The oldest rocks are from the Bom Jesus unit, occurring in two distinct locations (BJ-I and BJ-II; Fig. S-1). The felsic rocks from BJ-I are finely banded migmatites, whereas BJ-II consists of tonalitic gneisses, both including metre scale mafic amphibolite xenoliths (Fig. S-1). The Bom Jesus tonalite has been dated at 3412 ± 8 Ma (Dantas et al., 2013Dantas, E.L., De Souza, Z.S., Wernick, E., Hackspacher, P.C., Martin, H., Xiaodong, D., Li, J.W. (2013) Crustal growth in the 3.4-2.7Ga São José de Campestre Massif, Borborema Province, NE Brazil. Precambrian Research 227, 120–156, https://doi.org/10.1016/j.precamres.2012.08.006.
), providing a minimum age for the amphibolite xenoliths. Besides a few migmatite hosted samples, the amphibolites are mafic in composition (7.6−12.7 wt. % MgO; 46.5−54.0 wt. % SiO2,) with elevated Fe2O3 (≤17.5 wt. %). They generally exhibit high incompatible trace element concentrations and variable degrees of LREE enrichment with relatively flat HREE (Supplementary Information for details). Their composition is therefore consistent with derivation from a mantle source, rather than a crustal progenitor. To investigate the source of these Palaeoarchean mafic rocks, 15 amphibolite xenoliths (8 samples from BJ-I and 7 samples from BJ-II) have been analysed for their 146Sm-142Nd compositions, as well as 2 tonalitic host samples. Except for 1 sample, the amphibolite xenoliths exhibit 142Nd/144Nd ratios lower than the terrestrial Nd standard (including 11 samples showing well resolved negative anomalies), with μ142Nd as low as −14.1 and an average of −10.2 ± 5.0 ppm (2 sd, n = 15) (Fig. 2, Table S-2). The tonalitic samples yield μ142Nd (−6.7 ± 3.6 and −3.3 ± 3.8) higher than most amphibolite samples (Fig. 2, Table S-2). Besides the most enriched mafic rocks from the Nuvvuagittuq greenstone belt in Canada (O’Neil et al., 2012O’Neil, J., Carlson, R.W., Paquette, J.L., Francis, D. (2012) Formation age and metamorphic history of the Nuvvuagittuq Greenstone Belt. Precambrian Research 220–221, 23–44, https://doi.org/10.1016/j.precamres.2012.07.009.
), the Bom Jesus amphibolite μ142Nd values are the lowest measured in mantle-derived rocks.Figure 1 Simplified geological map of the Borborema Province. Tectonic domains; MCD – Médio coreau domain; CD – Ceará domain; RGND – Rio grande do norte domain; TD- transversal domain; SD – Southern domain. Archean cratons; AC- Amazon craton; SFC – São Francisco craton. See Figure S-1 for detailed geological map.
Figure 2 μ142Nd for the Bom Jesus samples. Grey band shows external error on the standard. Dashed line shows the average μ142Nd = −10.2 for the amphibolite samples exhibiting μ142Nd outside of the JNdi-1 error. Errors on data points are 2σ. Duplicate samples are labelled.
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Discussion
The amphibolite xenoliths are included in felsic rocks and have been metamorphosed to upper amphibolite facies, which could raise concerns about the inherency of their light REE content and Nd isotopic composition. The amphibolites present variable Nb/La ratios with some showing evidence of Th mobility (Figs. S-3, S-4). Post-magmatic disturbance is also apparent from the long lived 147Sm-143Nd isotopic system (Table S-3), yielding a 147Sm-144Nd vs. 143Nd/144Nd best fit line with an age of 4049.9 ± 832.8 Ma, MSWD = 290 (n = 13), holding no geochronological meaning and suggesting some extent of open system behaviour. The short lived 146Sm-142Nd system is however much less susceptible to post-crystallisation disturbance because processes fractionating the light REE after 4 Ga have no incidence on the 142Nd/144Nd ratios, since 146Sm is extinct. Nevertheless, the possible effects of secondary alteration must be examined. The xenoliths high concentration in Ba, a large ion lithophile element (LILE), may indicate some secondary fluid alteration. Yet, they are not correlated with the μ142Nd values (Fig. S4h) suggesting that the 142Nd/144Nd ratios were not disturbed despite possible element mobility. The felsic host exhibits higher concentrations in SiO2, Al2O3, Na2O when compared to the amphibolites, but the lack of correlations with μ142Nd and their lower Nd and Nb content argues against crustal contamination affecting the amphibolites’ 142Nd/144Nd ratios (Supplementary Information). Consequently, the measured μ142Nd are interpreted as the original isotopic composition. Furthermore, the migmatite-hosted mafic xenoliths (BJ-I) show lower Sm/Nd ratios compared to the tonalite-hosted samples (BJ-II) (Fig. S-3, Table S-3). Still, all amphibolites exhibit uniform μ142Nd values (Fig. 2) with average values of −9.6 ± 4.8 (2 sd, n = 7; BJ-I) and −10.6 ± 5.3 (2 sd, n = 8; BJ-II), suggesting that the 142Nd/144Nd ratios of the amphibolites were not significantly affected by the crustal reworking processes recorded by their host, and are thus interpreted as representative of their source. Although most amphibolite samples display lower μ142Nd compared to the TTG samples, the average compositions for both rock types overlap within error. This could suggest an indistinguishable 142Nd composition between the xenoliths and the TTG. If so, the most likely scenario would be that the TTG were produced by melting the mafic amphibolite, from which they inherited their 142Nd composition.
Since variability in 142Nd/144Nd ratios requires Sm-Nd chemical fractionation during the Hadean, the isotopic composition measured in the 3.4 Ga Bom Jesus amphibolites, can only be explained by a few scenarios: 1) the amphibolites themselves are xenoliths of Hadean mafic rocks, 2) a recycled Hadean crustal component in their mantle source, and 3) derivation from a Hadean light REE-enriched mantle.
If older than 4 Ga, rocks with sub-chondritic Sm/Nd ratios would exhibit lower 142Nd/144Nd ratios compared to the terrestrial Nd standard. For example, a mafic crust with a 147Sm/144Nd ratio of 0.16 and formed at 4.32 Ga from a reservoir with chondritic Sm/Nd and present day 142Nd/144Nd corresponding to modern terrestrial mantle, would evolve to a μ142Nd of ∼ −10 (Figs. 3, S-5), similar to the average obtained for the Bom Jesus amphibolites. Their low 142Nd/144Nd ratios could therefore be consistent with preserved fragments of Hadean mafic crust. However, a Hadean suite of rocks with variable Sm/Nd ratios such as measured in the Bom Jesus amphibolites, would exhibit a range in μ142Nd, correlated with their Sm/Nd ratios. Such correlation is not observed for amphibolites (Fig. S-5). Post-magmatic processes have likely affected, to some extent, the original Sm/Nd ratios of the amphibolites, which may have obscured a potential relationship with μ142Nd, yet the relatively homogeneous μ142Nd values of ∼−10 ppm for most samples is more in accordance with post-4 Ga derivation from an enriched Hadean source.
Figure 3 μ142Nd evolution of the source of the Bom Jesus amphibolites. Horizontal line at μ142Nd = 0 represents a reservoir with chondritic Sm/Nd and present day μ142Nd corresponding to modern mantle. Blue dashed line represents a super-chondritic BSE (Frossard et al., 2022
Frossard, P., Israel, C., Bouvier, A., Boyet, M. (2022) Earth’s composition was modified by collisional erosion. Science 377, 1529–1532, https://doi.org/10.1126/science.abq7351.
; Johnston et al., 2022Johnston, S., Brandon, A., McLeod, C., Rankenburg, K., Becker, H., Copeland, P. (2022) Nd isotope variation between the Earth–Moon system and enstatite chondrites. Nature 611, 501–506, https://doi.org/10.1038/s41586-022-05265-0.
). Grey band as in Figure 2. Red and green envelopes represent modelled enriched and depleted reservoirs formed at 4470 Ma. Black dashed lines show these reservoirs formed at 4400 Ma and evolving to the same present day μ142Nd. Thin solid black lines correspond to the 147Sm/144Nd required to evolve to μ142Nd = −10 (average amphibolite value). Blue line shows a 4400 Ma reservoir derived from a super-chondritic BSE. The Bom Jesus samples are displaced around their interpreted age (3.4 Ga) for clarity. SW Greenland and NE Canada data are average μ142Nd values for distinct mantle-derived lithologies. Schapenburg komatiite, Dwalie Greenstone and Komati formation data show average values (Puchtel et al., 2016Puchtel, I.S., Blichert-Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182 W- 142 Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193, https://doi.org/10.1002/2016GC006324.
; Schneider et al., 2018Schneider, K.P., Hoffmann, J.E., Boyet, M., Münker, C., Kröner, A. (2018) Coexistence of enriched and modern-like 142Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa. Earth and Planetary Science Letters 487, 54–66, https://doi.org/10.1016/j.epsl.2018.01.022.
; Boyet et al., 2021Boyet, M., Garçon, M., Arndt, N., Carlson, R.W., Konc, Z. (2021) Residual liquid from deep magma ocean crystallization in the source of komatiites from the ICDP drill core in the Barberton Greenstone Belt. Geochimica et Cosmochimica Acta 304, 141–159, https://doi.org/10.1016/j.gca.2021.04.020.
). Ameralik dike data shows the lowest μ142Nd value measured (Rizo et al., 2012Rizo, H., Boyet, M., Blichert-Toft, J., O’Neil, J., Rosing, M.T., Paquette, J.L. (2012) The elusive Hadean enriched reservoir revealed by 142Nd deficits in Isua Archaean rocks. Nature 491, 96–100, https://doi.org/10.1038/nature11565.
).Rather than being direct remnants of Hadean crust, the low 142Nd/144Nd ratios of the Bom Jesus amphibolites could be the result of a recycled Hadean crust in their mantle source (Hasenstab-Dübeler et al., 2022
Hasenstab-Dübeler, E., Tusch, J., Hoffmann, J.E., Fischer-Gödde, M., Szilas, K., Münker, C. (2022) Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements. Chemical Geology 614, 121141, https://doi.org/10.1016/j.chemgeo.2022.121141.
; Tusch et al., 2022Tusch, J., Hoffmann, J.E., Hasenstab, E., Fischer-Gödde, M., Marien, C.S., Wilson, A.H., Münker, C. (2022) Long-term preservation of Hadean protocrust in Earth’s mantle. Proceedings of the National Academy of Sciences 119, https://doi.org/10.1073/pnas.2120241119.
). A similar model involving a contaminated source has been proposed to explain negative μ142Nd values measured in mafic rocks from the Nuvvuagittuq belt in NE Canada (Caro et al., 2017Caro, G., Morino, P., Mojzsis, S.J., Cates, N.L., Bleeker, W. (2017) Sluggish Hadean geodynamics: Evidence from coupled 146,147Sm–142,143Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec). Earth and Planetary Science Letters 457, 23–37, https://doi.org/10.1016/j.epsl.2016.09.051.
), but the correlation between their 142Nd/144Nd and Sm/Nd ratios has also been interpreted as reflective of their Hadean age (O’Neil et al., 2008O’Neil, J., Carlson, R.W., Francis, D., Stevenson, R.K. (2008) Neodymium-142 evidence for hadean mafic crust. Science 321, 1828–1831, https://doi.org/10.1126/science.1161925.
). Regardless, the distinct geochemical compositions of the Bom Jesus and Nuvvuagittuq mafic rocks, as well as the contrasting extent of variations in μ142Nd values that they exhibit (Fig. 4), suggest that different processes were involved. If subduction-like processes occurred at the time of the Bom Jesus amphibolite formation, one could propose that a Hadean mafic crust carrying a low 142Nd/144Nd ratio, subducting during the Palaeoarchean, may have imprinted its 142Nd isotopic composition in the mantle source of the amphibolites. This could produce mantle-derived rocks with a range in μ142Nd, but expected to be correlated with light REE or other elements mobilised by such a process (Caro et al., 2017Caro, G., Morino, P., Mojzsis, S.J., Cates, N.L., Bleeker, W. (2017) Sluggish Hadean geodynamics: Evidence from coupled 146,147Sm–142,143Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec). Earth and Planetary Science Letters 457, 23–37, https://doi.org/10.1016/j.epsl.2016.09.051.
). The homogenous μ142Nd of the Bom Jesus amphibolites and lack of correlation with common subduction setting geochemical indicators (Figs. S-3, S-4), however, argues against inheritance of the 142Nd composition from a Hadean subducting slab. This rather suggests that the low 142Nd/144Nd composition was characteristic of their mantle source. Alternative models without subduction may be able to produce crustal material with variable 142Nd isotopic compositions interacting with the mantle. For example, a recent model proposed the differentiation of ∼4.5 Ga proto-crust, producing a restitic material that would then mix with an Archean mantle to produce a hybrid source (Tusch et al., 2022Tusch, J., Hoffmann, J.E., Hasenstab, E., Fischer-Gödde, M., Marien, C.S., Wilson, A.H., Münker, C. (2022) Long-term preservation of Hadean protocrust in Earth’s mantle. Proceedings of the National Academy of Sciences 119, https://doi.org/10.1073/pnas.2120241119.
). With the right amount of mixing, timing and extent of differentiations, such an intricate model could produce a mantle source with a 142Nd isotopic composition consistent with that of the Bom Jesus amphibolites, but no evidence supports a similar complex multi-stage process. This hybrid source is also inconsistent with the high concentrations in incompatible trace elements of the Bom Jesus amphibolites (up to ∼55 ppm Nd) and would require an unrealistically low degree of partial melting (<2 %) to produce similarly enriched mafic magmas.Figure 4 μ142Nd histograms for ≤3.4 Ga mantle-derived rocks. Data from this study; Bennett et al. (2007)
Bennett, V.C., Brandon, A.D., Nutman, A.P. (2007) Coupled 142Nd-143Nd isotopic evidence for hadean mantle dynamics. Science 318, 1907–1910, https://doi.org/10.1126/science.1145928.
; O’Neil et al. (2008O’Neil, J., Carlson, R.W., Francis, D., Stevenson, R.K. (2008) Neodymium-142 evidence for hadean mafic crust. Science 321, 1828–1831, https://doi.org/10.1126/science.1161925.
, 2012O’Neil, J., Carlson, R.W., Paquette, J.L., Francis, D. (2012) Formation age and metamorphic history of the Nuvvuagittuq Greenstone Belt. Precambrian Research 220–221, 23–44, https://doi.org/10.1016/j.precamres.2012.07.009.
); Rizo et al. (2013Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M.T. (2013) Early mantle dynamics inferred from 142Nd variations in Archean rocks from southwest Greenland. Earth and Planetary Science Letters 377–378, 324–335, https://doi.org/10.1016/j.epsl.2013.07.012.
, 2016Rizo, H., Walker, R.J., Carlson, R.W., Touboul, M., Horan, M.F., Puchtel, I.S., Boyet, M., Rosing, M.T. (2016) Early Earth differentiation investigated through 142Nd, 182W, and highly siderophile element abundances in samples from Isua, Greenland. Geochimica et Cosmochimica Acta 175, 319–336, https://doi.org/10.1016/j.gca.2015.12.007.
); Morino et al. (2017)Morino, P., Caro, G., Reisberg, L., Schumacher, A. (2017) Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm–142,143Nd systematics in ultramafic rocks of the Saglek block (3.25–3.9 Ga; northern Labrador, Canada). Earth and Planetary Science Letters 463, 136–150, https://doi.org/10.1016/j.epsl.2017.01.044.
; Schneider et al. (2018)Schneider, K.P., Hoffmann, J.E., Boyet, M., Münker, C., Kröner, A. (2018) Coexistence of enriched and modern-like 142Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa. Earth and Planetary Science Letters 487, 54–66, https://doi.org/10.1016/j.epsl.2018.01.022.
; Boyet et al. (2021)Boyet, M., Garçon, M., Arndt, N., Carlson, R.W., Konc, Z. (2021) Residual liquid from deep magma ocean crystallization in the source of komatiites from the ICDP drill core in the Barberton Greenstone Belt. Geochimica et Cosmochimica Acta 304, 141–159, https://doi.org/10.1016/j.gca.2021.04.020.
. Nuvvuagittuq data in top panel are measured 142Nd compositions, while bottom panel shows the initial μ142Nd at 4.31 Ga if the rocks are considered Hadean (O’Neil et al., 2012O’Neil, J., Carlson, R.W., Paquette, J.L., Francis, D. (2012) Formation age and metamorphic history of the Nuvvuagittuq Greenstone Belt. Precambrian Research 220–221, 23–44, https://doi.org/10.1016/j.precamres.2012.07.009.
).Silicate differentiation events occurring while 146Sm was still extant would produce complementary incompatible trace element depleted and enriched reservoirs, respectively evolving to high and low 142Nd/144Nd ratios. The existence of an early enriched reservoir complementary to Earth’s modern mantle has been proposed to account for the higher 142Nd/144Nd ratios of terrestrial rocks compared to chondrites (Boyet and Carlson, 2005
Boyet, M., Carlson, R.W. (2005) 142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth. Science 309, 576–581, https://doi.org/10.1126/science.1113634.
), but recent studies proposed alternative scenarios that do not require early differentiation of the Earth’s mantle to explain this difference in 142Nd isotopic compositions (Bouvier and Boyet, 2016Bouvier, A., Boyet, M. (2016) Primitive Solar System materials and Earth share a common initial 142Nd abundance. Nature 537, 399–402, https://doi.org/10.1038/nature19351.
; Burkhardt et al., 2016Burkhardt, C., Borg, L.E., Brennecka, G.A., Shollenberger, Q.R., Dauphas, N., Kleine, T. (2016) A nucleosynthetic origin for the Earth’s anomalous 142 Nd composition. Nature 537, 394–398, https://doi.org/10.1038/nature18956.
). However, the positive μ142Nd values measured in a number Eoarchean mantle-derived rocks imply the formation of an early depleted mantle, perhaps formed through crystallisation of a magma ocean (Rizo et al., 2011Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M. (2011) Combined Nd and Hf isotope evidence for deep-seated source of Isua lavas. Earth and Planetary Science Letters 312, 267–279, https://doi.org/10.1016/j.epsl.2011.10.014.
; Li et al., 2017Li, C.F., Wang, X.C., Wilde, S.A., Li, X.H., Wang, Y.F., Li, Z. (2017) Differentiation of the early silicate Earth as recorded by 142Nd-143Nd in 3.8–3.0 Ga rocks from the Anshan Complex, North China Craton. Precambrian Research 301, 86–101, https://doi.org/10.1016/j.precamres.2017.09.001.
; Morino et al., 2017Morino, P., Caro, G., Reisberg, L., Schumacher, A. (2017) Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm–142,143Nd systematics in ultramafic rocks of the Saglek block (3.25–3.9 Ga; northern Labrador, Canada). Earth and Planetary Science Letters 463, 136–150, https://doi.org/10.1016/j.epsl.2017.01.044.
), and would still entail the concomitant formation of an early enriched reservoir (i.e. characterised by negative μ142Nd values). Not only the negative μ142Nd values of the Bom Jesus mafic xenolith suggest derivation from such low Sm/Nd early sources, but their unusually high concentrations in most incompatible trace elements, compared to predominant Archean basaltic rocks (Fig. S-3c), is also consistent with an enriched mantle source.Estimations of the chemical composition of an early formed enriched reservoir depend on its Sm/Nd ratio, size and μ142Nd of Bulk Silicate Earth (BSE). Nevertheless, it would most likely exhibit higher Nd contents compared to BSE. For instance, Boyet and Carlson (2005)
Boyet, M., Carlson, R.W. (2005) 142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth. Science 309, 576–581, https://doi.org/10.1126/science.1113634.
estimated that the Nd concentration of a small size, enriched reservoir (4 % of the mass of BSE), could be up to 7 times higher than that of the BSE. Although they considered the enriched reservoir as complementary to a depleted MORB mantle with an excess in 142Nd compared to BSE, which recent work showed is not required, it nevertheless supports the fact that an early enriched reservoir would exhibit relatively high Nd content. It is however difficult to constrain the exact nature of an early enriched source. Hofmann et al. (2022)Hofmann, A.W., Class, C., Goldstein, S.L. (2022) Size and Composition of the MORB+OIB Mantle Reservoir. Geochemistry, Geophysics, Geosystems 23, https://doi.org/10.1029/2022GC010339.
proposed an early enriched reservoir that originated as a mafic crust, while the early enriched reservoir modelled by Boyet and Carlson (2005)Boyet, M., Carlson, R.W. (2005) 142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth. Science 309, 576–581, https://doi.org/10.1126/science.1113634.
is ultramafic in composition. Regardless of the exact nature of the early enriched source of the Bom Jesus amphibolites, it needs to be capable of producing mafic magmas with high concentrations of incompatible trace elements.The extent of the 142Nd deficit characterising this early formed reservoir depends on the timing of its differentiation, its Sm/Nd ratio and the 142Nd composition of the source reservoir. If we consider an early enriched mantle derived from a BSE with chondritic Sm/Nd and present day μ142Nd = 0, and formed coevally to the SW Greenland early depleted mantle at 4.47 Ga (Rizo et al., 2011
Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M. (2011) Combined Nd and Hf isotope evidence for deep-seated source of Isua lavas. Earth and Planetary Science Letters 312, 267–279, https://doi.org/10.1016/j.epsl.2011.10.014.
), it would require a 147Sm/144Nd = 0.183 to evolve to a μ142Nd ∼−10, consistent with the source of the Bom Jesus amphibolites (Fig. 3). A later differentiation at 4.40 Ga would require a lower 147Sm/144Nd ratio of 0.175 to evolve to μ142Nd = −10. As illustrated on Figure 3, derivation at 4.40 Ga from a slightly super-chondritic BSE with initial μ142Nd = −7.6 (average value proposed by Frossard et al., 2022Frossard, P., Israel, C., Bouvier, A., Boyet, M. (2022) Earth’s composition was modified by collisional erosion. Science 377, 1529–1532, https://doi.org/10.1126/science.abq7351.
and Johnston et al., 2022Johnston, S., Brandon, A., McLeod, C., Rankenburg, K., Becker, H., Copeland, P. (2022) Nd isotope variation between the Earth–Moon system and enstatite chondrites. Nature 611, 501–506, https://doi.org/10.1038/s41586-022-05265-0.
) would increase the required 147Sm/144Nd ratio to 0.185 in order to produce the same μ142Nd of −10.Together, the geochemistry and 142Nd isotopic composition of the Bom Jesus amphibolites provide evidence for a Hadean enriched mantle reservoir. A number of mantle-derived rocks from the Kaapvaal craton alluded to an early formed enriched source (Fig. 4), but its existence is better evidenced by the unequivocal and well resolved negative 142Nd anomalies of the Bom Jesus amphibolites. With a μ142Nd value of ∼−10, the range of plausible compositions and ages for this enriched mantle indicates that it could be complementary to an early depleted source previously recorded by several Eoarchean mafic and ultramafic rocks from the North Atlantic craton (Fig. 4). The confirmation of a Hadean enriched mantle reservoir has major implications on our understanding of the complex differentiation processes occurring on the Earth shortly after its formation and for the Archean geodynamics. Considering that the age of the mafic xenoliths is similar to their felsic hosts, the Bom Jesus amphibolites and other rare mantle-derived rocks hinting at the existence of an early enriched reservoir characterised by negative μ142Nd values are interestingly of similar ages (Fig. 3), dated between 3.41 and 3.55 Ga, but located over distinct Archean cratons (Rizo et al., 2012
Rizo, H., Boyet, M., Blichert-Toft, J., O’Neil, J., Rosing, M.T., Paquette, J.L. (2012) The elusive Hadean enriched reservoir revealed by 142Nd deficits in Isua Archaean rocks. Nature 491, 96–100, https://doi.org/10.1038/nature11565.
; Dantas et al., 2013Dantas, E.L., De Souza, Z.S., Wernick, E., Hackspacher, P.C., Martin, H., Xiaodong, D., Li, J.W. (2013) Crustal growth in the 3.4-2.7Ga São José de Campestre Massif, Borborema Province, NE Brazil. Precambrian Research 227, 120–156, https://doi.org/10.1016/j.precamres.2012.08.006.
; Puchtel et al., 2016Puchtel, I.S., Blichert-Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182 W- 142 Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193, https://doi.org/10.1002/2016GC006324.
; Schneider et al., 2018Schneider, K.P., Hoffmann, J.E., Boyet, M., Münker, C., Kröner, A. (2018) Coexistence of enriched and modern-like 142Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa. Earth and Planetary Science Letters 487, 54–66, https://doi.org/10.1016/j.epsl.2018.01.022.
; Boyet et al., 2021Boyet, M., Garçon, M., Arndt, N., Carlson, R.W., Konc, Z. (2021) Residual liquid from deep magma ocean crystallization in the source of komatiites from the ICDP drill core in the Barberton Greenstone Belt. Geochimica et Cosmochimica Acta 304, 141–159, https://doi.org/10.1016/j.gca.2021.04.020.
). Several lines of evidence are suggesting a shift in global geodynamic setting in the mid to early Archean (e.g., Næraa et al., 2012Næraa, T., Scherstén, A., Rosing, M.T., Kemp, A.I.S., Hoffmann, J.E., Kokfelt, T.F., Whitehouse, M.J. (2012) Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago. Nature 485, 627–630, https://doi.org/10.1038/nature11140
; Bauer et al., 2017Bauer, A.M., Fisher, C.M., Vervoort, J.D., Bowring, S.A. (2017) Coupled zircon Lu–Hf and U–Pb isotopic analyses of the oldest terrestrial crust, the >4.03 Ga Acasta Gneiss Complex. Earth and Planetary Science Letters 458, 37–48, https://doi.org/10.1016/j.epsl.2016.10.036.
; Reimink et al., 2018Reimink, J.R., Chacko, T., Carlson, R.W., Shirey, S.B., Liu, J., Stern, R.A., Bauer, A.M., Pearson, D.G., Heaman, L.M. (2018) Petrogenesis and tectonics of the Acasta Gneiss Complex derived from integrated petrology and 142Nd and 182W extinct nuclide-geochemistry. Earth and Planetary Science Letters 494, 12–22, https://doi.org/10.1016/j.epsl.2018.04.047.
; Hawkesworth et al., 2019Hawkesworth, C., Cawood, P.A., Dhuime, B. (2019) Rates of generation and growth of the continental crust. Geoscience Frontiers 10, 165–173, https://doi.org/10.1016/j.gsf.2018.02.004.
; Drabon et al., 2022Drabon, N., Byerly, B.L., Byerly, G.R., Wooden, J.L., Wiedenbeck, M., Valley, J.W., Kitajima, K., Bauer, A.M., Lowe, D.R. (2022) Destabilization of Long-Lived Hadean Protocrust and the Onset of Pervasive Hydrous Melting at 3.8 Ga. AGU Advances 3, 1–17, https://doi.org/10.1029/2021AV000520
), which coincides with the emplacement of most rocks consistent with derivation from this Hadean enriched source, as well as the apparent disappearance, or at least attenuation, of rocks derived from the early depleted mantle.top
Acknowledgments
This manuscript greatly benefited from useful reviews from Da Wang, Tsuyoshi Iizuka, an anonymous reviewer and editorial handling of Ambre Luguet. We thank Shuangquan Zhang and Hanika Rizo for their assistance in the lab and thoughtful scientific discussions. We also thank the Conselho Nacional de desenvolvimento científico e tecnológico (CNPq) for the support during field activities and sample acquisition. This research was supported by a Natural Sciences and Engineering Research Council of Canada Discovery grant to JO (RGPIN-2020-06323) and the NSERC Collaborative Research and Training Experience Program (545104).
Editor: Ambre Luguet
top
References
Bauer, A.M., Fisher, C.M., Vervoort, J.D., Bowring, S.A. (2017) Coupled zircon Lu–Hf and U–Pb isotopic analyses of the oldest terrestrial crust, the >4.03 Ga Acasta Gneiss Complex. Earth and Planetary Science Letters 458, 37–48, https://doi.org/10.1016/j.epsl.2016.10.036.
Show in context Several lines of evidence are suggesting a shift in global geodynamic setting in the mid to early Archean (e.g., Næraa et al., 2012; Bauer et al., 2017; Reimink et al., 2018; Hawkesworth et al., 2019; Drabon et al., 2022), which coincides with the emplacement of most rocks consistent with derivation from this Hadean enriched source, as well as the apparent disappearance, or at least attenuation, of rocks derived from the early depleted mantle.
View in article
Bennett, V.C., Brandon, A.D., Nutman, A.P. (2007) Coupled 142Nd-143Nd isotopic evidence for hadean mantle dynamics. Science 318, 1907–1910, https://doi.org/10.1126/science.1145928.
Show in context High precision measurements of short lived isotopic systems can however provide insights into the early differentiation of the silicate Earth and growing evidence from systems such as 146Sm-142Nd, 182Hf-182W and 129I-129Xe, supports a complex differentiation history of the mantle during the first few tens to hundreds of million years of Earth’s evolution (Bennett et al., 2007; Willbold et al., 2011; Tucker and Mukhopadhyay, 2014).
View in article
Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where , have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006; Rizo et al., 2011; Morino et al., 2017; Hasenstab-Dübeler et al., 2022).
View in article
More importantly, our results provide clear evidence for the existence of a Hadean enriched mantle, potentially complementary to the early depleted reservoir recorded by the Eoarchean mantle-derived rocks from the North Atlantic and North China cratons (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017).
View in article
Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
Bouvier, A., Boyet, M. (2016) Primitive Solar System materials and Earth share a common initial 142Nd abundance. Nature 537, 399–402, https://doi.org/10.1038/nature19351.
Show in context The existence of an early enriched reservoir complementary to Earth’s modern mantle has been proposed to account for the higher 142Nd/144Nd ratios of terrestrial rocks compared to chondrites (Boyet and Carlson, 2005), but recent studies proposed alternative scenarios that do not require early differentiation of the Earth’s mantle to explain this difference in 142Nd isotopic compositions (Bouvier and Boyet, 2016; Burkhardt et al., 2016).
View in article
Boyet, M., Carlson, R.W. (2005) 142Nd Evidence for Early (>4.53 Ga) Global Differentiation of the Silicate Earth. Science 309, 576–581, https://doi.org/10.1126/science.1113634.
Show in context The existence of an early enriched reservoir complementary to Earth’s modern mantle has been proposed to account for the higher 142Nd/144Nd ratios of terrestrial rocks compared to chondrites (Boyet and Carlson, 2005), but recent studies proposed alternative scenarios that do not require early differentiation of the Earth’s mantle to explain this difference in 142Nd isotopic compositions (Bouvier and Boyet, 2016; Burkhardt et al., 2016).
View in article
Nevertheless, it would most likely exhibit higher Nd contents compared to BSE. For instance, Boyet and Carlson (2005) estimated that the Nd concentration of a small size, enriched reservoir (4 % of the mass of BSE), could be up to 7 times higher than that of the BSE.
View in article
It is however difficult to constrain the exact nature of an early enriched source. Hofmann et al. (2022) proposed an early enriched reservoir that originated as a mafic crust, while the early enriched reservoir modelled by Boyet and Carlson (2005) is ultramafic in composition.
View in article
Boyet, M., Garçon, M., Arndt, N., Carlson, R.W., Konc, Z. (2021) Residual liquid from deep magma ocean crystallization in the source of komatiites from the ICDP drill core in the Barberton Greenstone Belt. Geochimica et Cosmochimica Acta 304, 141–159, https://doi.org/10.1016/j.gca.2021.04.020.
Show in context Only sparse Palaeoarchean (3.6 to 3.2 Ga) mantle-derived rocks hint at an early enriched mantle source, with few resolved negative μ142Nd anomalies (Rizo et al., 2012; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021), whose existence remains unclear.
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Schapenburg komatiite, Dwalie Greenstone and Komati formation data show average values (Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
Considering that the age of the mafic xenoliths is similar to their felsic hosts, the Bom Jesus amphibolites and other rare mantle-derived rocks hinting at the existence of an early enriched reservoir characterised by negative μ142Nd values are interestingly of similar ages (Fig. 3), dated between 3.41 and 3.55 Ga, but located over distinct Archean cratons (Rizo et al., 2012; Dantas et al., 2013; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Burkhardt, C., Borg, L.E., Brennecka, G.A., Shollenberger, Q.R., Dauphas, N., Kleine, T. (2016) A nucleosynthetic origin for the Earth’s anomalous 142 Nd composition. Nature 537, 394–398, https://doi.org/10.1038/nature18956.
Show in context The existence of an early enriched reservoir complementary to Earth’s modern mantle has been proposed to account for the higher 142Nd/144Nd ratios of terrestrial rocks compared to chondrites (Boyet and Carlson, 2005), but recent studies proposed alternative scenarios that do not require early differentiation of the Earth’s mantle to explain this difference in 142Nd isotopic compositions (Bouvier and Boyet, 2016; Burkhardt et al., 2016).
View in article
Carlson, R.W., Boyet, M., O’Neil, J., Rizo, H., Walker, R.J. (2015) Early Differentiation and its Long-Term Consequences for Earth Evolution. In: Badro, J., Walter, M. (Eds.) The Early Earth: Accretion and Differentiation, 143–172.
Show in context These differentiation processes were consequential on the composition of Earth’s various geochemical reservoirs (Carlson et al., 2015), but have been greatly obscured by more than four billion years of geological activity.
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Caro, G., Bourdon, B., Birck, J.L., Moorbath, S. (2006) High-precision 142Nd/144Nd measurements in terrestrial rocks: Constraints on the early differentiation of the Earth’s mantle. Geochimica et Cosmochimica Acta 70, 164–191, https://doi.org/10.1016/j.gca.2005.08.015.
Show in context Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where , have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006; Rizo et al., 2011; Morino et al., 2017; Hasenstab-Dübeler et al., 2022).
View in article
More importantly, our results provide clear evidence for the existence of a Hadean enriched mantle, potentially complementary to the early depleted reservoir recorded by the Eoarchean mantle-derived rocks from the North Atlantic and North China cratons (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017).
View in article
Caro, G., Morino, P., Mojzsis, S.J., Cates, N.L., Bleeker, W. (2017) Sluggish Hadean geodynamics: Evidence from coupled 146,147Sm–142,143Nd systematics in Eoarchean supracrustal rocks of the Inukjuak domain (Québec). Earth and Planetary Science Letters 457, 23–37, https://doi.org/10.1016/j.epsl.2016.09.051.
Show in context Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008; Caro et al., 2017; O’Neil and Carlson, 2017; Reimink et al., 2018; Guitreau et al., 2019; Wang et al., 2023), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle.
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A similar model involving a contaminated source has been proposed to explain negative μ142Nd values measured in mafic rocks from the Nuvvuagittuq belt in NE Canada (Caro et al., 2017), but the correlation between their 142Nd/144Nd and Sm/Nd ratios has also been interpreted as reflective of their Hadean age (O’Neil et al., 2008).
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This could produce mantle-derived rocks with a range in μ142Nd, but expected to be correlated with light REE or other elements mobilised by such a process (Caro et al., 2017).
View in article
Dantas, E.L., De Souza, Z.S., Wernick, E., Hackspacher, P.C., Martin, H., Xiaodong, D., Li, J.W. (2013) Crustal growth in the 3.4-2.7Ga São José de Campestre Massif, Borborema Province, NE Brazil. Precambrian Research 227, 120–156, https://doi.org/10.1016/j.precamres.2012.08.006.
Show in context The São José do Campestre Massif is an Archean basement inlier occurring within the Neoproterozoic Borborema Province of NE Brazil (Dantas et al., 2013) (Fig. 1).
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It includes gneisses from the tonalite-trondhjemite-granodiorite (TTG) series and supracrustal sequences, with ages from 3.4 to 2.7 Ga (Dantas et al., 2013.
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The Bom Jesus tonalite has been dated at 3412 ± 8 Ma (Dantas et al., 2013), providing a minimum age for the amphibolite xenoliths.
View in article
Considering that the age of the mafic xenoliths is similar to their felsic hosts, the Bom Jesus amphibolites and other rare mantle-derived rocks hinting at the existence of an early enriched reservoir characterised by negative μ142Nd values are interestingly of similar ages (Fig. 3), dated between 3.41 and 3.55 Ga, but located over distinct Archean cratons (Rizo et al., 2012; Dantas et al., 2013; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Drabon, N., Byerly, B.L., Byerly, G.R., Wooden, J.L., Wiedenbeck, M., Valley, J.W., Kitajima, K., Bauer, A.M., Lowe, D.R. (2022) Destabilization of Long-Lived Hadean Protocrust and the Onset of Pervasive Hydrous Melting at 3.8 Ga. AGU Advances 3, 1–17, https://doi.org/10.1029/2021AV000520.
Show in context Several lines of evidence are suggesting a shift in global geodynamic setting in the mid to early Archean (e.g., Næraa et al., 2012; Bauer et al., 2017; Reimink et al., 2018; Hawkesworth et al., 2019; Drabon et al., 2022), which coincides with the emplacement of most rocks consistent with derivation from this Hadean enriched source, as well as the apparent disappearance, or at least attenuation, of rocks derived from the early depleted mantle.
View in article
Frossard, P., Israel, C., Bouvier, A., Boyet, M. (2022) Earth’s composition was modified by collisional erosion. Science 377, 1529–1532, https://doi.org/10.1126/science.abq7351.
Show in context It has been suggested that the Earth formed, at least in part, from already differentiated bodies (e.g., Kruijer et al., 2014; Frossard et al., 2022).
View in article
Blue dashed line represents a super-chondritic BSE (Frossard et al., 2022; Johnston et al., 2022).
View in article
As illustrated on Figure 3, derivation at 4.40 Ga from a slightly super-chondritic BSE with initial μ142Nd = −7.6 (average value proposed by Frossard et al., 2022 and Johnston et al., 2022) would increase the required 147Sm/144Nd ratio to 0.185 in order to produce the same μ142Nd of −10.
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Guitreau, M., Boyet, M., Paquette, J.-L., Gannoun, A., Konc, Z., Benbakkar, M., Suchorski, K., Hénot, J.-M. (2019) Hadean protocrust reworking at the origin of the Archean Napier Complex (Antarctica). Geochemical Perspectives Letters 12, 7–11, https://doi.org/10.7185/geochemlet.1927.
Show in context Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008; Caro et al., 2017; O’Neil and Carlson, 2017; Reimink et al., 2018; Guitreau et al., 2019; Wang et al., 2023), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle.
View in article
Hawkesworth, C., Cawood, P.A., Dhuime, B. (2019) Rates of generation and growth of the continental crust. Geoscience Frontiers 10, 165–173, https://doi.org/10.1016/j.gsf.2018.02.004.
Show in context Several lines of evidence are suggesting a shift in global geodynamic setting in the mid to early Archean (e.g., Næraa et al., 2012; Bauer et al., 2017; Reimink et al., 2018; Hawkesworth et al., 2019; Drabon et al., 2022), which coincides with the emplacement of most rocks consistent with derivation from this Hadean enriched source, as well as the apparent disappearance, or at least attenuation, of rocks derived from the early depleted mantle.
View in article
Hasenstab-Dübeler, E., Tusch, J., Hoffmann, J.E., Fischer-Gödde, M., Szilas, K., Münker, C. (2022) Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements. Chemical Geology 614, 121141, https://doi.org/10.1016/j.chemgeo.2022.121141.
Show in context Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where , have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006; Rizo et al., 2011; Morino et al., 2017; Hasenstab-Dübeler et al., 2022).
View in article
Rather than being direct remnants of Hadean crust, the low 142Nd/144Nd ratios of the Bom Jesus amphibolites could be the result of a recycled Hadean crust in their mantle source (Hasenstab-Dübeler et al., 2022; Tusch et al., 2022).
View in article
Hofmann, A.W., Class, C., Goldstein, S.L. (2022) Size and Composition of the MORB+OIB Mantle Reservoir. Geochemistry, Geophysics, Geosystems 23, https://doi.org/10.1029/2022GC010339.
Show in context It is however difficult to constrain the exact nature of an early enriched source. Hofmann et al. (2022) proposed an early enriched reservoir that originated as a mafic crust, while the early enriched reservoir modelled by Boyet and Carlson (2005) is ultramafic in composition.
View in article
Johnston, S., Brandon, A., McLeod, C., Rankenburg, K., Becker, H., Copeland, P. (2022) Nd isotope variation between the Earth–Moon system and enstatite chondrites. Nature 611, 501–506, https://doi.org/10.1038/s41586-022-05265-0.
Show in context Blue dashed line represents a super-chondritic BSE (Frossard et al., 2022; Johnston et al., 2022).
View in article
As illustrated on Figure 3, derivation at 4.40 Ga from a slightly super-chondritic BSE with initial μ142Nd = −7.6 (average value proposed by Frossard et al., 2022 and Johnston et al., 2022) would increase the required 147Sm/144Nd ratio to 0.185 in order to produce the same μ142Nd of −10.
View in article
Kruijer, T.S., Touboul, M., Fischer-Gödde, M., Bermingham, K.R., Walker, R.J., Kleine, T. (2014) Protracted core formation and rapid accretion of protoplanets. Science 344, 1150–1154, https://doi.org/10.1126/science.1251766.
Show in context It has been suggested that the Earth formed, at least in part, from already differentiated bodies (e.g., Kruijer et al., 2014; Frossard et al., 2022).
View in article
Li, C.F., Wang, X.C., Wilde, S.A., Li, X.H., Wang, Y.F., Li, Z. (2017) Differentiation of the early silicate Earth as recorded by 142Nd-143Nd in 3.8–3.0 Ga rocks from the Anshan Complex, North China Craton. Precambrian Research 301, 86–101, https://doi.org/10.1016/j.precamres.2017.09.001.
Show in context Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where , have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006; Rizo et al., 2011; Morino et al., 2017; Hasenstab-Dübeler et al., 2022).
View in article
More importantly, our results provide clear evidence for the existence of a Hadean enriched mantle, potentially complementary to the early depleted reservoir recorded by the Eoarchean mantle-derived rocks from the North Atlantic and North China cratons (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017).
View in article
However, the positive μ142Nd values measured in a number Eoarchean mantle-derived rocks imply the formation of an early depleted mantle, perhaps formed through crystallisation of a magma ocean (Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), and would still entail the concomitant formation of an early enriched reservoir (i.e. characterised by negative μ142Nd values).
View in article
Morino, P., Caro, G., Reisberg, L., Schumacher, A. (2017) Chemical stratification in the post-magma ocean Earth inferred from coupled 146,147Sm–142,143Nd systematics in ultramafic rocks of the Saglek block (3.25–3.9 Ga; northern Labrador, Canada). Earth and Planetary Science Letters 463, 136–150, https://doi.org/10.1016/j.epsl.2017.01.044.
Show in context Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where , have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006; Rizo et al., 2011; Morino et al., 2017; Hasenstab-Dübeler et al., 2022).
View in article
More importantly, our results provide clear evidence for the existence of a Hadean enriched mantle, potentially complementary to the early depleted reservoir recorded by the Eoarchean mantle-derived rocks from the North Atlantic and North China cratons (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017).
View in article
Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
However, the positive μ142Nd values measured in a number Eoarchean mantle-derived rocks imply the formation of an early depleted mantle, perhaps formed through crystallisation of a magma ocean (Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), and would still entail the concomitant formation of an early enriched reservoir (i.e. characterised by negative μ142Nd values).
View in article
Næraa, T., Scherstén, A., Rosing, M.T., Kemp, A.I.S., Hoffmann, J.E., Kokfelt, T.F., Whitehouse, M.J. (2012) Hafnium isotope evidence for a transition in the dynamics of continental growth 3.2 Gyr ago. Nature 485, 627–630, https://doi.org/10.1038/nature11140.
Show in context Several lines of evidence are suggesting a shift in global geodynamic setting in the mid to early Archean (e.g., Næraa et al., 2012; Bauer et al., 2017; Reimink et al., 2018; Hawkesworth et al., 2019; Drabon et al., 2022), which coincides with the emplacement of most rocks consistent with derivation from this Hadean enriched source, as well as the apparent disappearance, or at least attenuation, of rocks derived from the early depleted mantle.
View in article
O’Neil, J., Carlson, R.W., Francis, D., Stevenson, R.K. (2008) Neodymium-142 evidence for hadean mafic crust. Science 321, 1828–1831, https://doi.org/10.1126/science.1161925.
Show in context Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008; Caro et al., 2017; O’Neil and Carlson, 2017; Reimink et al., 2018; Guitreau et al., 2019; Wang et al., 2023), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle.
View in article
A similar model involving a contaminated source has been proposed to explain negative μ142Nd values measured in mafic rocks from the Nuvvuagittuq belt in NE Canada (Caro et al., 2017), but the correlation between their 142Nd/144Nd and Sm/Nd ratios has also been interpreted as reflective of their Hadean age (O’Neil et al., 2008).
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Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
O’Neil, J., Carlson, R.W., Paquette, J.L., Francis, D. (2012) Formation age and metamorphic history of the Nuvvuagittuq Greenstone Belt. Precambrian Research 220–221, 23–44, https://doi.org/10.1016/j.precamres.2012.07.009.
Show in context Besides the most enriched mafic rocks from the Nuvvuagittuq greenstone belt in Canada (O’Neil et al., 2012), the Bom Jesus amphibolite μ142Nd values are the lowest measured in mantle-derived rocks.
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Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
O’Neil, J., Carlson, R.W. (2017) Building Archean cratons from Hadean mafic crust. Science 355, 1199–1202, https://doi.org/10.1126/science.aah3823.
Show in context Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008; Caro et al., 2017; O’Neil and Carlson, 2017; Reimink et al., 2018; Guitreau et al., 2019; Wang et al., 2023), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle.
View in article
Puchtel, I.S., Blichert-Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182 W- 142 Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193, https://doi.org/10.1002/2016GC006324.
Show in context Only sparse Palaeoarchean (3.6 to 3.2 Ga) mantle-derived rocks hint at an early enriched mantle source, with few resolved negative μ142Nd anomalies (Rizo et al., 2012; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021), whose existence remains unclear.
View in article
Schapenburg komatiite, Dwalie Greenstone and Komati formation data show average values (Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Considering that the age of the mafic xenoliths is similar to their felsic hosts, the Bom Jesus amphibolites and other rare mantle-derived rocks hinting at the existence of an early enriched reservoir characterised by negative μ142Nd values are interestingly of similar ages (Fig. 3), dated between 3.41 and 3.55 Ga, but located over distinct Archean cratons (Rizo et al., 2012; Dantas et al., 2013; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Reimink, J.R., Chacko, T., Carlson, R.W., Shirey, S.B., Liu, J., Stern, R.A., Bauer, A.M., Pearson, D.G., Heaman, L.M. (2018) Petrogenesis and tectonics of the Acasta Gneiss Complex derived from integrated petrology and 142Nd and 182W extinct nuclide-geochemistry. Earth and Planetary Science Letters 494, 12–22, https://doi.org/10.1016/j.epsl.2018.04.047.
Show in context Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008; Caro et al., 2017; O’Neil and Carlson, 2017; Reimink et al., 2018; Guitreau et al., 2019; Wang et al., 2023), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle.
View in article
Several lines of evidence are suggesting a shift in global geodynamic setting in the mid to early Archean (e.g., Næraa et al., 2012; Bauer et al., 2017; Reimink et al., 2018; Hawkesworth et al., 2019; Drabon et al., 2022), which coincides with the emplacement of most rocks consistent with derivation from this Hadean enriched source, as well as the apparent disappearance, or at least attenuation, of rocks derived from the early depleted mantle.
View in article
Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M. (2011) Combined Nd and Hf isotope evidence for deep-seated source of Isua lavas. Earth and Planetary Science Letters 312, 267–279, https://doi.org/10.1016/j.epsl.2011.10.014.
Show in context Variations in 142Nd/144Nd ratios imply Sm-Nd fractionation occurring in the Hadean (>4.0 billion year old [Ga]), while 146Sm (t½ = 103 Myr) was decaying. Positive μ142Nd values, where , have been measured in Eoarchean (4.0 to 3.6 Ga) mantle-derived rocks (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), supporting the formation of a depleted mantle reservoir circa 4.4 Ga (Caro et al., 2006; Rizo et al., 2011; Morino et al., 2017; Hasenstab-Dübeler et al., 2022).
View in article
More importantly, our results provide clear evidence for the existence of a Hadean enriched mantle, potentially complementary to the early depleted reservoir recorded by the Eoarchean mantle-derived rocks from the North Atlantic and North China cratons (Caro et al., 2006; Bennett et al., 2007; Rizo et al., 2011; Li et al., 2017; Morino et al., 2017).
View in article
However, the positive μ142Nd values measured in a number Eoarchean mantle-derived rocks imply the formation of an early depleted mantle, perhaps formed through crystallisation of a magma ocean (Rizo et al., 2011; Li et al., 2017; Morino et al., 2017), and would still entail the concomitant formation of an early enriched reservoir (i.e. characterised by negative μ142Nd values).
View in article
If we consider an early enriched mantle derived from a BSE with chondritic Sm/Nd and present day μ142Nd = 0, and formed coevally to the SW Greenland early depleted mantle at 4.47 Ga (Rizo et al., 2011), it would require a 147Sm/144Nd = 0.183 to evolve to a μ142Nd ∼−10, consistent with the source of the Bom Jesus amphibolites (Fig. 3).
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Rizo, H., Boyet, M., Blichert-Toft, J., O’Neil, J., Rosing, M.T., Paquette, J.L. (2012) The elusive Hadean enriched reservoir revealed by 142Nd deficits in Isua Archaean rocks. Nature 491, 96–100, https://doi.org/10.1038/nature11565.
Show in context
Only sparse Palaeoarchean (3.6 to 3.2 Ga) mantle-derived rocks hint at an early enriched mantle source, with few resolved negative μ142Nd anomalies (Rizo et al., 2012; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021), whose existence remains unclear.
View in article
Ameralik dike data shows the lowest μ142Nd value measured (Rizo et al., 2012).
View in article
Considering that the age of the mafic xenoliths is similar to their felsic hosts, the Bom Jesus amphibolites and other rare mantle-derived rocks hinting at the existence of an early enriched reservoir characterised by negative μ142Nd values are interestingly of similar ages (Fig. 3), dated between 3.41 and 3.55 Ga, but located over distinct Archean cratons (Rizo et al., 2012; Dantas et al., 2013; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M.T. (2013) Early mantle dynamics inferred from 142Nd variations in Archean rocks from southwest Greenland. Earth and Planetary Science Letters 377–378, 324–335, https://doi.org/10.1016/j.epsl.2013.07.012.
Show in context Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
Rizo, H., Walker, R.J., Carlson, R.W., Touboul, M., Horan, M.F., Puchtel, I.S., Boyet, M., Rosing, M.T. (2016) Early Earth differentiation investigated through 142Nd, 182W, and highly siderophile element abundances in samples from Isua, Greenland. Geochimica et Cosmochimica Acta 175, 319–336, https://doi.org/10.1016/j.gca.2015.12.007.
Show in context Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
Schneider, K.P., Hoffmann, J.E., Boyet, M., Münker, C., Kröner, A. (2018) Coexistence of enriched and modern-like 142Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa. Earth and Planetary Science Letters 487, 54–66, https://doi.org/10.1016/j.epsl.2018.01.022.
Show in context Only sparse Palaeoarchean (3.6 to 3.2 Ga) mantle-derived rocks hint at an early enriched mantle source, with few resolved negative μ142Nd anomalies (Rizo et al., 2012; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021), whose existence remains unclear.
View in article
Schapenburg komatiite, Dwalie Greenstone and Komati formation data show average values (Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Data from this study; Bennett et al. (2007); O’Neil et al. (2008, 2012); Rizo et al. (2013, 2016); Morino et al. (2017); Schneider et al. (2018); Boyet et al. (2021).
View in article
Considering that the age of the mafic xenoliths is similar to their felsic hosts, the Bom Jesus amphibolites and other rare mantle-derived rocks hinting at the existence of an early enriched reservoir characterised by negative μ142Nd values are interestingly of similar ages (Fig. 3), dated between 3.41 and 3.55 Ga, but located over distinct Archean cratons (Rizo et al., 2012; Dantas et al., 2013; Puchtel et al., 2016; Schneider et al., 2018; Boyet et al., 2021).
View in article
Tucker, J.M., Mukhopadhyay, S. (2014) Evidence for multiple magma ocean outgassing and atmospheric loss episodes from mantle noble gases. Earth and Planetary Science Letters 393, 254–265, https://doi.org/10.1016/j.epsl.2014.02.050.
Show in context High precision measurements of short lived isotopic systems can however provide insights into the early differentiation of the silicate Earth and growing evidence from systems such as 146Sm-142Nd, 182Hf-182W and 129I-129Xe, supports a complex differentiation history of the mantle during the first few tens to hundreds of million years of Earth’s evolution (Bennett et al., 2007; Willbold et al., 2011; Tucker and Mukhopadhyay, 2014).
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Tusch, J., Hoffmann, J.E., Hasenstab, E., Fischer-Gödde, M., Marien, C.S., Wilson, A.H., Münker, C. (2022) Long-term preservation of Hadean protocrust in Earth’s mantle. Proceedings of the National Academy of Sciences 119, https://doi.org/10.1073/pnas.2120241119.
Show in context Rather than being direct remnants of Hadean crust, the low 142Nd/144Nd ratios of the Bom Jesus amphibolites could be the result of a recycled Hadean crust in their mantle source (Hasenstab-Dübeler et al., 2022; Tusch et al., 2022).
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Alternative models without subduction may be able to produce crustal material with variable 142Nd isotopic compositions interacting with the mantle. For example, a recent model proposed the differentiation of ∼4.5 Ga proto-crust, producing a restitic material that would then mix with an Archean mantle to produce a hybrid source (Tusch et al., 2022).
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Wang, D., Qiu, X.-F., Carlson, R.W. (2023) The Eoarchean Muzidian gneiss complex: Long-lived Hadean crustal components in the building of Archean continents. Earth and Planetary Science Letters 605, 118037, https://doi.org/10.1016/j.epsl.2023.118037.
Show in context Negative μ142Nd values have been measured in ancient rocks from NE and NW Canada, central China, and Antarctica (O’Neil et al., 2008; Caro et al., 2017; O’Neil and Carlson, 2017; Reimink et al., 2018; Guitreau et al., 2019; Wang et al., 2023), but are believed to be associated with early crust formation or crustal reworking, rather than tracing an enriched mantle.
View in article
Willbold, M., Elliott, T., Moorbath, S. (2011) The tungsten isotopic composition of the Earth’s mantle before the terminal bombardment. Nature 477, 195–198, https://doi.org/10.1038/nature10399.
Show in context High precision measurements of short lived isotopic systems can however provide insights into the early differentiation of the silicate Earth and growing evidence from systems such as 146Sm-142Nd, 182Hf-182W and 129I-129Xe, supports a complex differentiation history of the mantle during the first few tens to hundreds of million years of Earth’s evolution (Bennett et al., 2007; Willbold et al., 2011; Tucker and Mukhopadhyay, 2014).
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Supplementary Information
The Supplementary Information includes:
- Methods
- Geological context
- Major and trace element compositions
- Nd isotopic compositions and disturbance
- Supplementary Figures S-1 to S-6
- Tables S-1 to S-3
- Supplementary Information References
Download the Supplementary Information (PDF)
Download Table S-1 (xlsx)
Download Table S-2 (xlsx)
Download Table S-3 (xlsx)
Figures
Figure 1 Simplified geological map of the Borborema Province. Tectonic domains; MCD – Médio coreau domain; CD – Ceará domain; RGND – Rio grande do norte domain; TD- transversal domain; SD – Southern domain. Archean cratons; AC- Amazon craton; SFC – São Francisco craton. See Figure S-1 for detailed geological map.
Figure 2 μ142Nd for the Bom Jesus samples. Grey band shows external error on the standard. Dashed line shows the average μ142Nd = −10.2 for the amphibolite samples exhibiting μ142Nd outside of the JNdi-1 error. Errors on data points are 2σ. Duplicate samples are labelled.
Figure 3 μ142Nd evolution of the source of the Bom Jesus amphibolites. Horizontal line at μ142Nd = 0 represents a reservoir with chondritic Sm/Nd and present day μ142Nd corresponding to modern mantle. Blue dashed line represents a super-chondritic BSE (Frossard et al., 2022
Frossard, P., Israel, C., Bouvier, A., Boyet, M. (2022) Earth’s composition was modified by collisional erosion. Science 377, 1529–1532, https://doi.org/10.1126/science.abq7351.
; Johnston et al., 2022Johnston, S., Brandon, A., McLeod, C., Rankenburg, K., Becker, H., Copeland, P. (2022) Nd isotope variation between the Earth–Moon system and enstatite chondrites. Nature 611, 501–506, https://doi.org/10.1038/s41586-022-05265-0.
). Grey band as in Figure 2. Red and green envelopes represent modelled enriched and depleted reservoirs formed at 4470 Ma. Black dashed lines show these reservoirs formed at 4400 Ma and evolving to the same present day μ142Nd. Thin solid black lines correspond to the 147Sm/144Nd required to evolve to μ142Nd = −10 (average amphibolite value). Blue line shows a 4400 Ma reservoir derived from a super-chondritic BSE. The Bom Jesus samples are displaced around their interpreted age (3.4 Ga) for clarity. SW Greenland and NE Canada data are average μ142Nd values for distinct mantle-derived lithologies. Schapenburg komatiite, Dwalie Greenstone and Komati formation data show average values (Puchtel et al., 2016Puchtel, I.S., Blichert-Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182 W- 142 Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193, https://doi.org/10.1002/2016GC006324.
; Schneider et al., 2018Schneider, K.P., Hoffmann, J.E., Boyet, M., Münker, C., Kröner, A. (2018) Coexistence of enriched and modern-like 142Nd signatures in Archean igneous rocks of the eastern Kaapvaal Craton, southern Africa. Earth and Planetary Science Letters 487, 54–66, https://doi.org/10.1016/j.epsl.2018.01.022.
; Boyet et al., 2021Boyet, M., Garçon, M., Arndt, N., Carlson, R.W., Konc, Z. (2021) Residual liquid from deep magma ocean crystallization in the source of komatiites from the ICDP drill core in the Barberton Greenstone Belt. Geochimica et Cosmochimica Acta 304, 141–159, https://doi.org/10.1016/j.gca.2021.04.020.
). Ameralik dike data shows the lowest μ142Nd value measured (Rizo et al., 2012Rizo, H., Boyet, M., Blichert-Toft, J., O’Neil, J., Rosing, M.T., Paquette, J.L. (2012) The elusive Hadean enriched reservoir revealed by 142Nd deficits in Isua Archaean rocks. Nature 491, 96–100, https://doi.org/10.1038/nature11565.
).
Figure 4 μ142Nd histograms for ≤3.4 Ga mantle-derived rocks. Data from this study; Bennett et al. (2007)
Bennett, V.C., Brandon, A.D., Nutman, A.P. (2007) Coupled 142Nd-143Nd isotopic evidence for hadean mantle dynamics. Science 318, 1907–1910, https://doi.org/10.1126/science.1145928.
; O’Neil et al. (2008O’Neil, J., Carlson, R.W., Francis, D., Stevenson, R.K. (2008) Neodymium-142 evidence for hadean mafic crust. Science 321, 1828–1831, https://doi.org/10.1126/science.1161925.
, 2012O’Neil, J., Carlson, R.W., Paquette, J.L., Francis, D. (2012) Formation age and metamorphic history of the Nuvvuagittuq Greenstone Belt. Precambrian Research 220–221, 23–44, https://doi.org/10.1016/j.precamres.2012.07.009.
); Rizo et al. (2013Rizo, H., Boyet, M., Blichert-Toft, J., Rosing, M.T. (2013) Early mantle dynamics inferred from 142Nd variations in Archean rocks from southwest Greenland. Earth and Planetary Science Letters 377–378, 324–335, https://doi.org/10.1016/j.epsl.2013.07.012.
, 2016Rizo, H., Walker, R.J., Carlson, R.W., Touboul, M., Horan, M.F., Puchtel, I.S., Boyet, M., Rosing, M.T. (2016) Early Earth differentiation investigated through 142Nd, 182W, and highly siderophile element abundances in samples from Isua, Greenland. Geochimica et Cosmochimica Acta 175, 319–336, https://doi.org/10.1016/j.gca.2015.12.007.
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. Nuvvuagittuq data in top panel are measured 142Nd compositions, while bottom panel shows the initial μ142Nd at 4.31 Ga if the rocks are considered Hadean (O’Neil et al., 2012O’Neil, J., Carlson, R.W., Paquette, J.L., Francis, D. (2012) Formation age and metamorphic history of the Nuvvuagittuq Greenstone Belt. Precambrian Research 220–221, 23–44, https://doi.org/10.1016/j.precamres.2012.07.009.
).