Neoarchean marine chemical sediments as archives of Hadean silicate differentiation
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Keywords: Hadean, Mantle, BIF
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Abstract
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
) and only remnants can be observed. Here, we apply the short lived isotopic system 146Sm-142Nd to an alternative archive—marine chemical sediments—and show that alternating Fe- and Si-rich bands from the 2.7 billion-year-old Temagami banded iron formation (BIF), Canada, display significantly different 142Nd isotopic compositions. The Fe-rich bands yield a depleted signature (expressed as deviation from the standard in μ notation) with an average μ142Nd of +7.02 ± 0.71, while the Si-rich bands display modern mantle-like signatures (average μ142Nd −2.83 ± 2.32) likely being the results of mixing between different sources. These complementary signatures reflect the dominant, locally derived source of Nd in the seawater at the time of deposition. Our results promote that layering in BIFs is a syn-depositional feature, and that BIFs are unique geochemical archives capable of recording silicate reservoirs that formed during the Hadean but were still extant during the Neoarchean.Figures
 Figure 1 μ142Nd of the Temagami BIF. Blue symbols are Si-rich layers, red symbols are Fe-rich bands. Samples are reproduced in stratigraphic order. All uncertainties are 2 s.d. Light grey band is the 2σ error on the terrestrial standard JNdi, light blue box is the weighted average and error on the chert samples and the light red box is the weighted average and error on the magnetite layer. See text for details. |  Figure 2 Model showing the evolution of μ142Nd through time, based on extraction of a Tonalite-Trondhjemite-Granodiorite (TTG) from a mafic (blue) or felsic (orange shaded area) source at 4.3 and 4.1 Ga (from O’Neil and Carlson, 2017). Model was calculated using the approach of Morino et al. (2017), using a modern-like terrestrial 142Nd composition as the bulk Earth, with a μ142Nd of 0. Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019). The green line is the model from Debaille et al. (2013) showing trend of mixing in the mantle required to progress from the most positive values at 3.8 Ga to the +7 found in Abitibi at 2.7 Ga. |
| Figure 1 | Figure 2 |
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Introduction
The 146Sm-142Nd radiogenic isotope system is the primary tool for tracing early Earth silicate differentiation due to the systems short half-life and decoupling of the parent and daughter elements during silicate differentiation. The parent isotope, 146Sm, was only present during the first ∼500 Ma of the solar system, and as such records silicate differentiation during the Hadean. To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where
), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (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
, 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
; 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
; 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
, 2016O’Neil, J., Rizo, H., Boyet, M., Carlson, R.W., Rosing, M.T. (2016) Geochemistry and Nd isotopic characteristics of Earth’s Hadean mantle and primitive crust. Earth and Planetary Science Letters 442, 194–205. https://doi.org/10.1016/j.epsl.2016.02.055
; 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
, 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
; Debaille et al., 2013Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
; 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
; 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
; Garcia et al., 2023Garcia, V.B., O’Neil, J., Dantas, E.L. (2023) Rare evidence for the existence of a Hadean enriched mantle reservoir. Geochemical Perspectives Letters 28, 1–6 https://doi.org/10.7185/geochemlet.2336
).The Superior Craton contains many well preserved and largely unmodified greenstone belts, including the Abitibi and Temagami. The Abitibi Greenstone Belt contains the youngest Archean rock to show a positive 142Nd anomaly, in 2.7 Ga tholeiite lavas (Debaille et al., 2013)
Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
. The Temagami region has suffered only minor metamorphism (lower greenschist facies; Jolly, 1982Jolly, W. (1982) Progressive Metamorphism of Komatiies and rekated Archean lavas of the Abibiti area, Canada. In: Arndt, N.T., Nisbet, E.G. (Eds.) Komatiites. George Allen and Unwin, London, 245–266.
) and hosts sedimentary deposits, including banded iron formations (BIF) that give internal Sm-Nd and Lu-Hf isochron ages of 2.7 Ga and for which the 143Nd isotope compositions have been shown to derive from local Abitibi seawater (Viehmann et al., 2014Viehmann, S., Hoffmann, J.E., Münker, C., Bau, M. (2014) Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents. Geology 42, 115–118. https://doi.org/10.1130/G35014.1
). The banded iron formation at Temagami is a layered marine chemical sediment with alternating bands of Fe-rich magnetite and Si-rich metachert, showing evidence that both high temperature hydrothermal fluids and subaerial terrestrial weathering affected 2.7 Ga Temagami seawater chemistry (Bau and Alexander, 2009Bau, M., Alexander, B.W. (2009) Distribution of high field strength elements (Y, Zr, REE, Hf, Ta, Th, U) in adjacent magnetite and chert bands and in reference standards FeR-3 and FeR-4 from the Temagami iron-formation, Canada, and the redox level of the Neoarchean ocean. Precambrian Research 174, 337–346. https://doi.org/10.1016/j.precamres.2009.08.007
; Viehmann et al., 2014Viehmann, S., Hoffmann, J.E., Münker, C., Bau, M. (2014) Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents. Geology 42, 115–118. https://doi.org/10.1130/G35014.1
; Bau et al., 2022Bau, M., Frei, R., Garbe-Schönberg, D., Viehmann, S. (2022) High-resolution Ge-Si-Fe, Cr isotope and Th-U data for the Neoarchean Temagami BIF, Canada, suggest primary origin of BIF bands and oxidative terrestrial weathering 2.7 Ga ago. Earth and Planetary Science Letters 589, 117579. https://doi.org/10.1016/j.epsl.2022.117579
; Mundl-Petermeier et al., 2022Mundl-Petermeier, A., Viehmann, S., Tusch, J., Bau, M., Kurzweil, F., Münker, C. (2022) Earth’s geodynamic evolution constrained by 182W in Archean seawater. Nature Communications 13, 2701. https://doi.org/10.1038/s41467-022-30423-3
). Previous work has shown that the Temagami BIF has unaltered rare earth element (Bau and Alexander, 2009Bau, M., Alexander, B.W. (2009) Distribution of high field strength elements (Y, Zr, REE, Hf, Ta, Th, U) in adjacent magnetite and chert bands and in reference standards FeR-3 and FeR-4 from the Temagami iron-formation, Canada, and the redox level of the Neoarchean ocean. Precambrian Research 174, 337–346. https://doi.org/10.1016/j.precamres.2009.08.007
; Supplementary Information), 143Nd and 176Hf isotope compositions (Viehmann et al., 2014Viehmann, S., Hoffmann, J.E., Münker, C., Bau, M. (2014) Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents. Geology 42, 115–118. https://doi.org/10.1130/G35014.1
). Recently, a multi-proxy approach on the Temagami BIF, using Ge/Si and Th/U ratios as well as Cr isotopes, indicated that the magnetite layers precipitated from ambient seawater with chemistry dominated by hydrothermal fluids, while the (meta)chert layers formed during periods when the ambient seawater chemistry was dominated by continental sources (Bau et al., 2022Bau, M., Frei, R., Garbe-Schönberg, D., Viehmann, S. (2022) High-resolution Ge-Si-Fe, Cr isotope and Th-U data for the Neoarchean Temagami BIF, Canada, suggest primary origin of BIF bands and oxidative terrestrial weathering 2.7 Ga ago. Earth and Planetary Science Letters 589, 117579. https://doi.org/10.1016/j.epsl.2022.117579
). As the BIF’s trace element composition derives directly from the sources contributing to local seawater, they provide a unique opportunity to investigate the 142Nd composition of these source lithologies at 2.7 Ga. Besides the importance of Nd as the daughter product in both a short lived and long lived chronometer, Nd is also particularly relevant when studying seawater-derived sediments, as its residence time in modern seawater (<700 years; Tachikawa et al., 1999Tachikawa, K., Jeandel, C., Roy-Barman, M. (1999) A new approach to the Nd residence time in the ocean: the role of atmospheric inputs. Earth and Planetary Science Letters 170, 433–446. https://doi.org/10.1016/S0012-821X(99)00127-2
) is significantly shorter than the global mixing time of the oceans (1500 years; Broecker and Peng, 1982Broecker, W.S., Peng, T.-H. (1982) Tracers in the Sea (vol. 690). Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York.
). Although the Nd residence time might be somewhat longer in Archean seawater under more reducing atmospheric and hydrospheric conditions and the resulting lack of abundant Fe and Mn (oxyhydr)oxide particles to scavenge REE, Nd and its isotopes are prime geochemical proxies in Archean marine chemical sediments (Viehmann et al., 2015Viehmann, S., Bau, M., Hoffmann, J.E., Münker, C. (2015) Geochemistry of the Krivoy Rog Banded Iron Formation, Ukraine, and the impact of peak episodes of increased global magmatic activity on the trace element composition of Precambrian seawater. Precambrian Research 270, 165–180. https://doi.org/10.1016/j.precamres.2015.09.015
). Hence, they trace the source of components affecting local seawater composition (e.g., Viehmann et al., 2015Viehmann, S., Bau, M., Hoffmann, J.E., Münker, C. (2015) Geochemistry of the Krivoy Rog Banded Iron Formation, Ukraine, and the impact of peak episodes of increased global magmatic activity on the trace element composition of Precambrian seawater. Precambrian Research 270, 165–180. https://doi.org/10.1016/j.precamres.2015.09.015
). This is in marked contrast to the 182W systematics in the Temagami BIF investigated by Mundl-Petermeier et al. (2022)Mundl-Petermeier, A., Viehmann, S., Tusch, J., Bau, M., Kurzweil, F., Münker, C. (2022) Earth’s geodynamic evolution constrained by 182W in Archean seawater. Nature Communications 13, 2701. https://doi.org/10.1038/s41467-022-30423-3
, where positive μ182W anomalies were observed. While μ182W tracks metal–silicate partitioning and earlier differentiation events than μ142Nd, generally they should show similar trends. The difference in the Temagami BIF can be explained due to tungsten’s long residence time in seawater, that exceeds the global mixing time of the oceans. As such, the positive anomalies reported by Mundl-Petermeier et al. (2022)Mundl-Petermeier, A., Viehmann, S., Tusch, J., Bau, M., Kurzweil, F., Münker, C. (2022) Earth’s geodynamic evolution constrained by 182W in Archean seawater. Nature Communications 13, 2701. https://doi.org/10.1038/s41467-022-30423-3
represent more global sources, while the μ142Nd discussed here rather represents the local source flux into the seawater.top
Methods and Results
Three spatially separate sections of BIF from the Temagami Greenstone Belt were sampled, and homogeneous powders of individual magnetite and metachert layers of each section analysed for high-precision 142Nd. Samples were processed through ion exchange chemistry adapted from the procedures of Debaille et al. (2013)
Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
, prior to 3-lines multi-static analysis by Thermal Ionisation Mass Spectrometer (see Supplementary Information for further details). The raw measurements are corrected for mass fractionation using an exponential law that will account for mass-dependent isotope fractionation. Any possible induced mass-independent fractionation due to nuclear field shift effect during chemical purification is unlikely due to the high Nd yield (>99 %). Sample TM1 shows the largest dissimilarity between the metachert and magnetite layers, with a difference of 10.4 μ units. The two different layers from TM2 are just outside of analytical uncertainty (∼4 μ unit) of each other, but the metachert layer is 4.3 μ units lower than the magnetite layer, exceeding the analytical uncertainty. Section TM3 shows the widest variability, with two of the three metachert layers giving an average composition of −3.7 ± 0.19 (2 s.d., error on the average, not analytical error), and one magnetite layer giving +6.6 ± 2.9 (2 s.d.). The two layers TM3-3 and TM3-4 share a similar composition of −0.9 ± 5.1 (2 s.d.) and +1.9 ± 4.1 (2 s.d.) and overlap within uncertainty, despite one being Fe-rich and the other Si-rich (Fig. 1). Due to the similarity of these two adjacent layers, we assume they do not represent a pure end member composition, potentially due to mixing during the resampling process. Therefore, they will not be considered in the following discussion. The Si- and Fe-rich samples of the Temagami BIF define two distinct end member compositions: the metachert bands typically have a lower (negative and close to the present day average) μ142Nd weighted average of −2.5 ± 3.8 (95 % confidence), whereas the magnetite bands are systematically positive with a weighted average of +7.0 ± 1.6 (95 % confidence, Table S-1). However, the 142Nd and 143Nd systematics are decoupled and the samples do not provide any hint on respective source’s model age in a two-stage evolution diagram (see Supplementary Information). As observed by Viehmann et al. (2014Viehmann, S., Hoffmann, J.E., Münker, C., Bau, M. (2014) Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents. Geology 42, 115–118. https://doi.org/10.1130/G35014.1
), the 143Nd systematics is below the expected evolution of the depleted MORB mantle (DMM) at 2.7 Ga. With the BIF giving ∼+0.2 ± 1.7 ɛ-unit in the present study (not considering TM1-2), compared to ∼+4 for the DMM at 2.7 Ga, this corroborates previous conclusions that both volcanic and more felsic sources affected ancient Temagami seawater. Such decoupling is also to be expected, considering that the 142Nd value of the mantle has stopped growing at 4 Ga, while 143Nd has continued to grow and mix after 4 Ga.Figure 1 μ142Nd of the Temagami BIF. Blue symbols are Si-rich layers, red symbols are Fe-rich bands. Samples are reproduced in stratigraphic order. All uncertainties are 2 s.d. Light grey band is the 2σ error on the terrestrial standard JNdi, light blue box is the weighted average and error on the chert samples and the light red box is the weighted average and error on the magnetite layer. See text for details.
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Discussion
We suggest here that the significant difference in 142Nd isotopic compositions between the Fe-rich and Si-rich BIF end members reflects 142Nd input from distinctly different sources that cannot be resolved by the long lived system 143Nd. As such, the short residence time of Nd in seawater allows us to detect this disparate source of the Nd, with the preservation and continued tapping of both, an early depleted reservoir, mostly represented by Fe-rich layers, and a modern-like reservoir, represented by Si layers, at 2.7 Ga. The distinct 142Nd compositions seen in the adjacent BIF bands also strongly support interpretations that the prominent banding in BIFs is a primary depositional feature (for a recent discussion see, e.g., Bau et al., 2022
Bau, M., Frei, R., Garbe-Schönberg, D., Viehmann, S. (2022) High-resolution Ge-Si-Fe, Cr isotope and Th-U data for the Neoarchean Temagami BIF, Canada, suggest primary origin of BIF bands and oxidative terrestrial weathering 2.7 Ga ago. Earth and Planetary Science Letters 589, 117579. https://doi.org/10.1016/j.epsl.2022.117579
). The 182W results (Mundl-Petermeier et al., 2022Mundl-Petermeier, A., Viehmann, S., Tusch, J., Bau, M., Kurzweil, F., Münker, C. (2022) Earth’s geodynamic evolution constrained by 182W in Archean seawater. Nature Communications 13, 2701. https://doi.org/10.1038/s41467-022-30423-3
) also support the banding as a depositional feature, as the metachert and magnetite layers have distinctly different 182W compositions. Interestingly, the 182W results have excesses in both the metachert and the magnetite layers, with the former showing a stronger excess in 182W. Due to the significantly longer marine residence time of W than Nd (e.g., Sohrin et al., 1987Sohrin, Y., Isshiki, K., Kuwamoto, T., Nakayama, E. (1987) Tungsten in north pacific waters. Marine Chemistry 22, 95–103. https://doi.org/10.1016/0304-4203(87)90051-X
), it is not surprising that the 142Nd and 182W results seem to disagree as they are tracing different mixing scales, with 182W tracing the rather global seawater composition and the 142Nd rather tracing local input into Temagami seawater.Remarkably, the 142Nd composition of the depleted end member, with a consistent positive μ142Nd anomaly and a weighted average of +7.0 ± 1.6, perfectly matches the composition of the depleted mantle at 2.7 Ga observed in tholeiites from Theo’s Flow, located 200 km north of Temagami (Figs. 1, S-1; Debaille et al., 2013
Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
). This provides a highly constrained value for the 142Nd composition of the mantle beneath the Abitibi province at 2.7 Ga. Indeed, this mantle reservoir was not fully homogenised after its formation during the Hadean. It was still an active component during the Neoarchean and contributed positive 142Nd signatures to the seawater from which the Fe-rich bands precipitated, via high temperature hydrothermal fluids that leached submarine volcanics. Interestingly, the 2.7 Ga Boston Creek komatiite flow lies between Theo’s Flow and Temagami and has distinctly different μ142Nd of −3.8 ± 2.8 (Puchtel et al., 2018Puchtel, I.S., Blichert-Toft, J., Touboul, M., Walker, R.J. (2018) 182W and HSE constraints from 2.7 Ga komatiites on the heterogeneous nature of the Archean mantle. Geochimica et Cosmochimica Acta 228, 1–26. https://doi.org/10.1016/j.gca.2018.02.030
). This flow is unique amongst the Archean komatiites with a deficit in highly siderophile elements compared to the modern mantle, chondritic 187Os/188Os coupled with a positive 182W anomaly. Puchtel et al. (2018)Puchtel, I.S., Blichert-Toft, J., Touboul, M., Walker, R.J. (2018) 182W and HSE constraints from 2.7 Ga komatiites on the heterogeneous nature of the Archean mantle. Geochimica et Cosmochimica Acta 228, 1–26. https://doi.org/10.1016/j.gca.2018.02.030
concluded that the Boston Creek flow was sourced from a mantle that formed early in Earth’s history and was then isolated from the convecting mantle for ≥1.8 billion years. While this would require there to be several heterogeneous mantle domains beneath the Abitibi Greenstone Belt, it supports the conclusion of this study, that the local mantle was not well homogenised and pockets of Hadean-formed mantle remained well into the Neoarchean.In contrast, the weighted average for the metachert bands is not fully resolvable from the modern homogenised value of 0 ± 3 μ-units, even though it tends towards negative values (Fig. 1). We emphasise, however, that these metachert bands (like most BIF-hosted metacherts) also carry an Fe oxide component which, for example, even dominates the Ga-Al systematics of the metchert bands of the Temagami BIF (Ernst et al., 2023
Ernst, D.M., Garbe-Schönberg, D., Kraemer, D., Bau, M. (2023) A first look at the gallium-aluminium systematics of Early Earth’s seawater: Evidence from Neoarchean banded iron formation. Geochimica et Cosmochimica Acta 355, 48–61. https://doi.org/10.1016/j.gca.2023.06.019
). Hence, the μ142Nd of −2.5 ± 3.8 for the metachert bands represents a mixture between (i) Nd provided by continental run-off derived from enriched crust and (ii) hydrothermal Nd input from vent fluids that had leached seafloor basalts (i.e. depleted mantle), resulting in a ’modern’ 142Nd signature.A negative μ142Nd value is expected for crust that differentiated from the mantle within the first 500 Myr of the Earth. The extent of this anomaly would depend on both the Sm/Nd ratio of the crust and the age of differentiation, both parameters not being accessible. In addition, erosion results in the mixing of different crustal sources of widely varying age and composition or it could represent the actual composition of the locally derived continental crust, which also contained Eoarchean rocks in the Superior craton (e.g., Böhm et al., 2003
Böhm, C.O., Heaman, L.M., Stern, R.A., Corkery, M.T., Creaser, R.A. (2003) Nature of assean lake ancient crust, Manitoba: a combined SHRIMP–ID-TIMS U–Pb geochronology and Sm–Nd isotope study. Precambrian Research 126, 55–94. https://doi.org/10.1016/S0301-9268(03)00127-X
). Within seawater, a number of different factors are at play, such as continued input of chemically weathered crustal material mixing with a weakened, but still present, mantle component due to ongoing, but reduced, hydrothermal activity. Regardless, knowing the local mantle was characterised by a μ142Nd value of +7, obtaining an Archean μ142Nd value close to 0 requires that locally some crust with negative μ142Nd was involved in the mixing, and as such was derived from sources that formed while 146Sm was extant, that is, during the Hadean. Intriguingly, the 143Nd systematics of the BIF measured in the present study clearly indicate a mixture between the DMM and an enriched end member (see Supplementary Information) that cannot be identified, while the 142Nd systematics retains a larger spread, with the magnetite bands matching the composition of the DMM at 2.7 Ga. However, modelling of this mixing cannot be performed in absence of Nd concentrations of the respective end members, especially in seawater. Following the approach (Fig. 2) of O’Neil and Carlson (2017)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
, and considering that 142Nd can directly identify the enriched end member, its minimum differentiation age from a mafic precursor should be late (∼4.1 Ga). This suggests a time span of at least 1.4 Ga for the longevity of the Hadean crust, implying a low recycling rate.Figure 2 Model showing the evolution of μ142Nd through time, based on extraction of a Tonalite-Trondhjemite-Granodiorite (TTG) from a mafic (blue) or felsic (orange shaded area) source at 4.3 and 4.1 Ga (from O’Neil and Carlson, 2017
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
). Model was calculated using the approach of 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
, using a modern-like terrestrial 142Nd composition as the bulk Earth, with a μ142Nd of 0. Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017Caro, 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
; 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
, 2016O’Neil, J., Rizo, H., Boyet, M., Carlson, R.W., Rosing, M.T. (2016) Geochemistry and Nd isotopic characteristics of Earth’s Hadean mantle and primitive crust. Earth and Planetary Science Letters 442, 194–205. https://doi.org/10.1016/j.epsl.2016.02.055
; 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
, 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
; Debaille et al., 2013Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
; Puchtel et al., 2013Puchtel, I.S., Blichert-Toft, J., Touboul, M., Walker, R.J., Byerly, G.R., Nisbet, E.G., Anhaeusser, C.R. (2013) Insights into early Earth from Barberton komatiites: Evidence from lithophile isotope and trace element systematics. Geochimica et Cosmochimica Acta 108, 63–90. https://doi.org/10.1016/j.gca.2013.01.016
, 2016Puchtel, I.S., Blichert‐Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182W-142Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193. https://doi.org/10.1002/2016GC006324
; Roth et al., 2013Roth, A.S.G., Bourdon, B., Mojzsis, S.J., Touboul, M., Sprung, P., Guitreau, M., Blichert-Toft, J. (2013) Inherited 142Nd anomalies in Eoarchean protoliths. Earth and Planetary Science Letters 361, 50–57. https://doi.org/10.1016/j.epsl.2012.11.023
, 2014Roth, A.S.G., Bourdon, B., Mojzsis, S.J., Rudge, J.F., Guitreau, M., Blichert‐Toft, J. (2014) Combined 147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust. Geochemistry, Geophysics, Geosystems 15, 2329–2345. https://doi.org/10.1002/2014GC005313
; 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 3.8–3.0Ga rocks from the Anshan Complex, North China Craton. Precambrian Research 301, 86–101. https://doi.org/10.1016/j.precamres.2017.09.001
; Maya et al., 2017Maya, J.M., Bhutani, R., Balakrishnan, S., Rajee Sandhya, S. (2017) Petrogenesis of 3.15 Ga old Banasandra komatiites from the Dharwar craton, India: Implications for early mantle heterogeneity. Geoscience Frontiers 8, 467–481. https://doi.org/10.1016/j.gsf.2016.03.007
; 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
; 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
; 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
; Wainwright et al., 2019Wainwright, A.N., El Atrassi, F., Debaille, V., Mattielli, N. (2019) Geochemistry and petrogenesis of Archean mafic rocks from the Amsaga area, West African craton, Mauritania. Precambrian Research 324, 208–219. https://doi.org/10.1016/j.precamres.2019.02.005
). The green line is the model from Debaille et al. (2013)Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
showing trend of mixing in the mantle required to progress from the most positive values at 3.8 Ga to the +7 found in Abitibi at 2.7 Ga.top
Implications of Archean mantle geodynamics
The Neoarchean is considered by some to be a transitional period from a stagnant lid to a plate tectonic-like global regime (Debaille et al., 2013
Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
; Cawood et al., 2018Cawood, P.A., Hawkesworth, C.J., Pisarevsky, S.A., Dhuime, B., Capitanio, F.A., Nebel, O. (2018) Geological archive of the onset of plate tectonics. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, 20170405. https://doi.org/10.1098/rsta.2017.0405
), with evidence of this seen in parts of the Superior Craton where there are cyclic subduction episodes and periods of stagnant lid quiescence (Wyman, 2018Wyman, D. (2018) Do cratons preserve evidence of stagnant lid tectonics? Geoscience Frontiers 9, 3–17. https://doi.org/10.1016/j.gsf.2017.02.001
). It is also the time of amalgamation of the Superior Craton, which happened during the formation of the Temagami BIF (Wyman, 2018Wyman, D. (2018) Do cratons preserve evidence of stagnant lid tectonics? Geoscience Frontiers 9, 3–17. https://doi.org/10.1016/j.gsf.2017.02.001
). Nevertheless, there has been much debate about how the Abitibi Greenstone Belt formed, with two competing theories involving cyclic subduction or a mantle plume (van Hunen and Moyen, 2012van Hunen, J., Moyen, J.-F. (2012) Archean Subduction: Fact or Fiction? Annual Review of Earth and Planetary Sciences 40, 195–219. https://doi.org/10.1146/annurev-earth-042711-105255
; Wyman, 2018Wyman, D. (2018) Do cratons preserve evidence of stagnant lid tectonics? Geoscience Frontiers 9, 3–17. https://doi.org/10.1016/j.gsf.2017.02.001
). While the data obtained in this study cannot exclude either of these hypotheses, it suggests that any subduction that could have occurred, should have only been short lived as it was unable to destroy all early crust (e.g., by erosion of uplifted continental margins) and to homogenise the depleted mantle reservoir—at least until 2.7 Ga. As such, the preservation of a depleted mantle reservoir and an enriched continental crust at 2.7 Ga in the Abitibi is of great significance. It reveals that, in spite of intense mantle convection (Debaille et al., 2013Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
, and references therein) and magmatic activity, any global homogenisation process in the Archean was slow, and that BIF and potentially other chemical sediments that are derived from seawater are important archives able to trace early formed Hadean silicate reservoirs even during the Archean.top
Acknowledgements
S. Cauchies is thanked for lab support. ANW and VD thank the ERC StG 336718 “ISoSyc” for financial support. VD also thanks the FRS-FNRS for support. SV acknowledges FWF project P34238. The authors also thank two anonymous reviewers for helping to improve this manuscript.
Editor: Helen Williams
top
References
Bau, M., Alexander, B.W. (2009) Distribution of high field strength elements (Y, Zr, REE, Hf, Ta, Th, U) in adjacent magnetite and chert bands and in reference standards FeR-3 and FeR-4 from the Temagami iron-formation, Canada, and the redox level of the Neoarchean ocean. Precambrian Research 174, 337–346. https://doi.org/10.1016/j.precamres.2009.08.007
Show in context The banded iron formation at Temagami is a layered marine chemical sediment with alternating bands of Fe-rich magnetite and Si-rich metachert, showing evidence that both high temperature hydrothermal fluids and subaerial terrestrial weathering affected 2.7 Ga Temagami seawater chemistry (Bau and Alexander, 2009; Viehmann et al., 2014; Bau et al., 2022; Mundl-Petermeier et al., 2022).
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Previous work has shown that the Temagami BIF has unaltered rare earth element (Bau and Alexander, 2009; Supplementary Information), 143Nd and 176Hf isotope compositions (Viehmann et al., 2014).
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Bau, M., Frei, R., Garbe-Schönberg, D., Viehmann, S. (2022) High-resolution Ge-Si-Fe, Cr isotope and Th-U data for the Neoarchean Temagami BIF, Canada, suggest primary origin of BIF bands and oxidative terrestrial weathering 2.7 Ga ago. Earth and Planetary Science Letters 589, 117579. https://doi.org/10.1016/j.epsl.2022.117579
Show in context The banded iron formation at Temagami is a layered marine chemical sediment with alternating bands of Fe-rich magnetite and Si-rich metachert, showing evidence that both high temperature hydrothermal fluids and subaerial terrestrial weathering affected 2.7 Ga Temagami seawater chemistry (Bau and Alexander, 2009; Viehmann et al., 2014; Bau et al., 2022; Mundl-Petermeier et al., 2022).
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Recently, a multi-proxy approach on the Temagami BIF, using Ge/Si and Th/U ratios as well as Cr isotopes, indicated that the magnetite layers precipitated from ambient seawater with chemistry dominated by hydrothermal fluids, while the (meta)chert layers formed during periods when the ambient seawater chemistry was dominated by continental sources (Bau et al., 2022).
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The distinct 142Nd compositions seen in the adjacent BIF bands also strongly support interpretations that the prominent banding in BIFs is a primary depositional feature (for a recent discussion see, e.g., Bau et al., 2022).
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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 Some of the early created complementary reservoirs dissipated with time (e.g., Bennett et al., 2007) and only remnants can be observed.
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To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Böhm, C.O., Heaman, L.M., Stern, R.A., Corkery, M.T., Creaser, R.A. (2003) Nature of assean lake ancient crust, Manitoba: a combined SHRIMP–ID-TIMS U–Pb geochronology and Sm–Nd isotope study. Precambrian Research 126, 55–94. https://doi.org/10.1016/S0301-9268(03)00127-X
Show in context In addition, erosion results in the mixing of different crustal sources of widely varying age and composition or it could represent the actual composition of the locally derived continental crust, which also contained Eoarchean rocks in the Superior craton (e.g., Böhm et al., 2003).
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Broecker, W.S., Peng, T.-H. (1982) Tracers in the Sea (vol. 690). Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York.
Show in context Besides the importance of Nd as the daughter product in both a short lived and long lived chronometer, Nd is also particularly relevant when studying seawater-derived sediments, as its residence time in modern seawater (<700 years; Tachikawa et al., 1999) is significantly shorter than the global mixing time of the oceans (1500 years; Broecker and Peng, 1982).
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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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
View in article
Cawood, P.A., Hawkesworth, C.J., Pisarevsky, S.A., Dhuime, B., Capitanio, F.A., Nebel, O. (2018) Geological archive of the onset of plate tectonics. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, 20170405. https://doi.org/10.1098/rsta.2017.0405
Show in context The Neoarchean is considered by some to be a transitional period from a stagnant lid to a plate tectonic-like global regime (Debaille et al., 2013; Cawood et al., 2018), with evidence of this seen in parts of the Superior Craton where there are cyclic subduction episodes and periods of stagnant lid quiescence (Wyman, 2018).
View in article
Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
Show in context To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
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The Abitibi Greenstone Belt contains the youngest Archean rock to show a positive 142Nd anomaly, in 2.7 Ga tholeiite lavas (Debaille et al., 2013).
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Samples were processed through ion exchange chemistry adapted from the procedures of Debaille et al. (2013), prior to 3-lines multi-static analysis by Thermal Ionisation Mass Spectrometer (see Supplementary Information for further details).
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Remarkably, the 142Nd composition of the depleted end member, with a consistent positive μ142Nd anomaly and a weighted average of +7.0 ± 1.6, perfectly matches the composition of the depleted mantle at 2.7 Ga observed in tholeiites from Theo’s Flow, located 200 km north of Temagami (Figs. 1, S-1; Debaille et al., 2013).
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Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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The green line is the model from Debaille et al. (2013) showing trend of mixing in the mantle required to progress from the most positive values at 3.8 Ga to the +7 found in Abitibi at 2.7 Ga.
View in article
The Neoarchean is considered by some to be a transitional period from a stagnant lid to a plate tectonic-like global regime (Debaille et al., 2013; Cawood et al., 2018), with evidence of this seen in parts of the Superior Craton where there are cyclic subduction episodes and periods of stagnant lid quiescence (Wyman, 2018).
View in article
It reveals that, in spite of intense mantle convection (Debaille et al., 2013, and references therein) and magmatic activity, any global homogenisation process in the Archean was slow, and that BIF and potentially other chemical sediments that are derived from seawater are important archives able to trace early formed Hadean silicate reservoirs even during the Archean.
View in article
Ernst, D.M., Garbe-Schönberg, D., Kraemer, D., Bau, M. (2023) A first look at the gallium-aluminium systematics of Early Earth’s seawater: Evidence from Neoarchean banded iron formation. Geochimica et Cosmochimica Acta 355, 48–61. https://doi.org/10.1016/j.gca.2023.06.019
Show in context We emphasise, however, that these metachert bands (like most BIF-hosted metacherts) also carry an Fe oxide component which, for example, even dominates the Ga-Al systematics of the metchert bands of the Temagami BIF (Ernst et al., 2023).
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Garcia, V.B., O’Neil, J., Dantas, E.L. (2023) Rare evidence for the existence of a Hadean enriched mantle reservoir. Geochemical Perspectives Letters 28, 1–6 https://doi.org/10.7185/geochemlet.2336
Show in context To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
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Jolly, W. (1982) Progressive Metamorphism of Komatiies and rekated Archean lavas of the Abibiti area, Canada. In: Arndt, N.T., Nisbet, E.G. (Eds.) Komatiites. George Allen and Unwin, London, 245–266.
Show in context The Temagami region has suffered only minor metamorphism (lower greenschist facies; Jolly, 1982) and hosts sedimentary deposits, including banded iron formations (BIF) that give internal Sm-Nd and Lu-Hf isochron ages of 2.7 Ga and for which the 143Nd isotope compositions have been shown to derive from local Abitibi seawater (Viehmann et al., 2014).
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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 3.8–3.0Ga 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 Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
View in article
Maya, J.M., Bhutani, R., Balakrishnan, S., Rajee Sandhya, S. (2017) Petrogenesis of 3.15 Ga old Banasandra komatiites from the Dharwar craton, India: Implications for early mantle heterogeneity. Geoscience Frontiers 8, 467–481. https://doi.org/10.1016/j.gsf.2016.03.007
Show in context Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
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Model was calculated using the approach of Morino et al. (2017), using a modern-like terrestrial 142Nd composition as the bulk Earth, with a μ142Nd of 0.
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Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Mundl-Petermeier, A., Viehmann, S., Tusch, J., Bau, M., Kurzweil, F., Münker, C. (2022) Earth’s geodynamic evolution constrained by 182W in Archean seawater. Nature Communications 13, 2701. https://doi.org/10.1038/s41467-022-30423-3
Show in context The banded iron formation at Temagami is a layered marine chemical sediment with alternating bands of Fe-rich magnetite and Si-rich metachert, showing evidence that both high temperature hydrothermal fluids and subaerial terrestrial weathering affected 2.7 Ga Temagami seawater chemistry (Bau and Alexander, 2009; Viehmann et al., 2014; Bau et al., 2022; Mundl-Petermeier et al., 2022).
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This is in marked contrast to the 182W systematics in the Temagami BIF investigated by Mundl-Petermeier et al. (2022), where positive μ182W anomalies were observed.
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As such, the positive anomalies reported by Mundl-Petermeier et al. (2022) represent more global sources, while the μ142Nd discussed here rather represents the local source flux into the seawater.
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The 182W results (Mundl-Petermeier et al., 2022) also support the banding as a depositional feature, as the metachert and magnetite layers have distinctly different 182W compositions.
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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 Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
View in article
O’Neil, J., Rizo, H., Boyet, M., Carlson, R.W., Rosing, M.T. (2016) Geochemistry and Nd isotopic characteristics of Earth’s Hadean mantle and primitive crust. Earth and Planetary Science Letters 442, 194–205. https://doi.org/10.1016/j.epsl.2016.02.055
Show in context To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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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 However, modelling of this mixing cannot be performed in absence of Nd concentrations of the respective end members, especially in seawater. Following the approach (Fig. 2) of O’Neil and Carlson (2017), and considering that 142Nd can directly identify the enriched end member, its minimum differentiation age from a mafic precursor should be late (∼4.1 Ga).
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Model showing the evolution of μ142Nd through time, based on extraction of a Tonalite-Trondhjemite-Granodiorite (TTG) from a mafic (blue) or felsic (orange shaded area) source at 4.3 and 4.1 Ga (from O’Neil and Carlson, 2017).
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Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Puchtel, I.S., Blichert-Toft, J., Touboul, M., Walker, R.J., Byerly, G.R., Nisbet, E.G., Anhaeusser, C.R. (2013) Insights into early Earth from Barberton komatiites: Evidence from lithophile isotope and trace element systematics. Geochimica et Cosmochimica Acta 108, 63–90. https://doi.org/10.1016/j.gca.2013.01.016
Show in context Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Puchtel, I.S., Blichert‐Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182W-142Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193. https://doi.org/10.1002/2016GC006324
Show in context Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Puchtel, I.S., Blichert-Toft, J., Touboul, M., Walker, R.J. (2018) 182W and HSE constraints from 2.7 Ga komatiites on the heterogeneous nature of the Archean mantle. Geochimica et Cosmochimica Acta 228, 1–26. https://doi.org/10.1016/j.gca.2018.02.030
Show in context Interestingly, the 2.7 Ga Boston Creek komatiite flow lies between Theo’s Flow and Temagami and has distinctly different μ142Nd of −3.8 ± 2.8 (Puchtel et al., 2018).
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Puchtel et al. (2018) concluded that the Boston Creek flow was sourced from a mantle that formed early in Earth’s history and was then isolated from the convecting mantle for ≥1.8 billion years.
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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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
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Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
View in article
Roth, A.S.G., Bourdon, B., Mojzsis, S.J., Touboul, M., Sprung, P., Guitreau, M., Blichert-Toft, J. (2013) Inherited 142Nd anomalies in Eoarchean protoliths. Earth and Planetary Science Letters 361, 50–57. https://doi.org/10.1016/j.epsl.2012.11.023
Show in context Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
View in article
Roth, A.S.G., Bourdon, B., Mojzsis, S.J., Rudge, J.F., Guitreau, M., Blichert‐Toft, J. (2014) Combined 147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust. Geochemistry, Geophysics, Geosystems 15, 2329–2345. https://doi.org/10.1002/2014GC005313
Show in context Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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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 To date, a wide number of (meta)igneous rock samples have been analysed which record μ142Nd anomalies (where ), positive if related to the Hadean depleted mantle and negative if derived from a trace element enriched reservoir (Caro et al., 2006, 2017; Bennett et al., 2007; O’Neil et al., 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Morino et al., 2017; Schneider et al., 2018; Garcia et al., 2023).
View in article
Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Sohrin, Y., Isshiki, K., Kuwamoto, T., Nakayama, E. (1987) Tungsten in north pacific waters. Marine Chemistry 22, 95–103. https://doi.org/10.1016/0304-4203(87)90051-X
Show in context Due to the significantly longer marine residence time of W than Nd (e.g., Sohrin et al., 1987), it is not surprising that the 142Nd and 182W results seem to disagree as they are tracing different mixing scales, with 182W tracing the rather global seawater composition and the 142Nd rather tracing local input into Temagami seawater.
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Tachikawa, K., Jeandel, C., Roy-Barman, M. (1999) A new approach to the Nd residence time in the ocean: the role of atmospheric inputs. Earth and Planetary Science Letters 170, 433–446. https://doi.org/10.1016/S0012-821X(99)00127-2
Show in context Besides the importance of Nd as the daughter product in both a short lived and long lived chronometer, Nd is also particularly relevant when studying seawater-derived sediments, as its residence time in modern seawater (<700 years; Tachikawa et al., 1999) is significantly shorter than the global mixing time of the oceans (1500 years; Broecker and Peng, 1982).
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van Hunen, J., Moyen, J.-F. (2012) Archean Subduction: Fact or Fiction? Annual Review of Earth and Planetary Sciences 40, 195–219. https://doi.org/10.1146/annurev-earth-042711-105255
Show in context Nevertheless, there has been much debate about how the Abitibi Greenstone Belt formed, with two competing theories involving cyclic subduction or a mantle plume (van Hunen and Moyen, 2012; Wyman, 2018).
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Viehmann, S., Hoffmann, J.E., Münker, C., Bau, M. (2014) Decoupled Hf-Nd isotopes in Neoarchean seawater reveal weathering of emerged continents. Geology 42, 115–118. https://doi.org/10.1130/G35014.1
Show in context The Temagami region has suffered only minor metamorphism (lower greenschist facies; Jolly, 1982) and hosts sedimentary deposits, including banded iron formations (BIF) that give internal Sm-Nd and Lu-Hf isochron ages of 2.7 Ga and for which the 143Nd isotope compositions have been shown to derive from local Abitibi seawater (Viehmann et al., 2014).
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The banded iron formation at Temagami is a layered marine chemical sediment with alternating bands of Fe-rich magnetite and Si-rich metachert, showing evidence that both high temperature hydrothermal fluids and subaerial terrestrial weathering affected 2.7 Ga Temagami seawater chemistry (Bau and Alexander, 2009; Viehmann et al., 2014; Bau et al., 2022; Mundl-Petermeier et al., 2022).
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Previous work has shown that the Temagami BIF has unaltered rare earth element (Bau and Alexander, 2009; Supplementary Information), 143Nd and 176Hf isotope compositions (Viehmann et al., 2014).
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As observed by Viehmann et al. (2014), the 143Nd systematics is below the expected evolution of the depleted MORB mantle (DMM) at 2.7 Ga. With the BIF giving ∼+0.2 ± 1.7 ɛ-unit in the present study (not considering TM1-2), compared to ∼+4 for the DMM at 2.7 Ga, this corroborates previous conclusions that both volcanic and more felsic sources affected ancient Temagami seawater.
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Viehmann, S., Bau, M., Hoffmann, J.E., Münker, C. (2015) Geochemistry of the Krivoy Rog Banded Iron Formation, Ukraine, and the impact of peak episodes of increased global magmatic activity on the trace element composition of Precambrian seawater. Precambrian Research 270, 165–180. https://doi.org/10.1016/j.precamres.2015.09.015
Show in context Although the Nd residence time might be somewhat longer in Archean seawater under more reducing atmospheric and hydrospheric conditions and the resulting lack of abundant Fe and Mn (oxyhydr)oxide particles to scavenge REE, Nd and its isotopes are prime geochemical proxies in Archean marine chemical sediments (Viehmann et al., 2015).
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Hence, they trace the source of components affecting local seawater composition (e.g., Viehmann et al., 2015).
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Wainwright, A.N., El Atrassi, F., Debaille, V., Mattielli, N. (2019) Geochemistry and petrogenesis of Archean mafic rocks from the Amsaga area, West African craton, Mauritania. Precambrian Research 324, 208–219. https://doi.org/10.1016/j.precamres.2019.02.005
Show in context Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017, Bennett et al., 2007; O’Neil et al., 2008, 2012, 2016; Rizo et al., 2012, 2013; Debaille et al., 2013; Puchtel et al., 2013, 2016; Roth et al., 2013, 2014; Li et al., 2017; Maya et al., 2017; Morino et al., 2017; O’Neil and Carlson, 2017; Schneider et al., 2018; Wainwright et al., 2019).
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Wyman, D. (2018) Do cratons preserve evidence of stagnant lid tectonics? Geoscience Frontiers 9, 3–17. https://doi.org/10.1016/j.gsf.2017.02.001
Show in context The Neoarchean is considered by some to be a transitional period from a stagnant lid to a plate tectonic-like global regime (Debaille et al., 2013; Cawood et al., 2018), with evidence of this seen in parts of the Superior Craton where there are cyclic subduction episodes and periods of stagnant lid quiescence (Wyman, 2018).
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It is also the time of amalgamation of the Superior Craton, which happened during the formation of the Temagami BIF (Wyman, 2018).
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Nevertheless, there has been much debate about how the Abitibi Greenstone Belt formed, with two competing theories involving cyclic subduction or a mantle plume (van Hunen and Moyen, 2012; Wyman, 2018).
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Supplementary Information
The Supplementary Information includes:
- Regional geology and sample description
- Methods
- Trace Elements
- 143Nd/144Nd modelling
- Tables S-1 to S-3
- Figures S-1 to S-5
- Supplementary Information References
Download the Supplementary Information (PDF)
Download Tables S-3 (.xlsx)
Figures
Figure 1 μ142Nd of the Temagami BIF. Blue symbols are Si-rich layers, red symbols are Fe-rich bands. Samples are reproduced in stratigraphic order. All uncertainties are 2 s.d. Light grey band is the 2σ error on the terrestrial standard JNdi, light blue box is the weighted average and error on the chert samples and the light red box is the weighted average and error on the magnetite layer. See text for details.
Figure 2 Model showing the evolution of μ142Nd through time, based on extraction of a Tonalite-Trondhjemite-Granodiorite (TTG) from a mafic (blue) or felsic (orange shaded area) source at 4.3 and 4.1 Ga (from O’Neil and Carlson, 2017
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
). Model was calculated using the approach of 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
, using a modern-like terrestrial 142Nd composition as the bulk Earth, with a μ142Nd of 0. Squares are data from this work, circles are the available 142Nd literature data (Caro et al., 2006, 2017Caro, 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
; 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
, 2016O’Neil, J., Rizo, H., Boyet, M., Carlson, R.W., Rosing, M.T. (2016) Geochemistry and Nd isotopic characteristics of Earth’s Hadean mantle and primitive crust. Earth and Planetary Science Letters 442, 194–205. https://doi.org/10.1016/j.epsl.2016.02.055
; 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
, 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
; Debaille et al., 2013Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
; Puchtel et al., 2013Puchtel, I.S., Blichert-Toft, J., Touboul, M., Walker, R.J., Byerly, G.R., Nisbet, E.G., Anhaeusser, C.R. (2013) Insights into early Earth from Barberton komatiites: Evidence from lithophile isotope and trace element systematics. Geochimica et Cosmochimica Acta 108, 63–90. https://doi.org/10.1016/j.gca.2013.01.016
, 2016Puchtel, I.S., Blichert‐Toft, J., Touboul, M., Horan, M.F., Walker, R.J. (2016) The coupled 182W-142Nd record of early terrestrial mantle differentiation. Geochemistry, Geophysics, Geosystems 17, 2168–2193. https://doi.org/10.1002/2016GC006324
; Roth et al., 2013Roth, A.S.G., Bourdon, B., Mojzsis, S.J., Touboul, M., Sprung, P., Guitreau, M., Blichert-Toft, J. (2013) Inherited 142Nd anomalies in Eoarchean protoliths. Earth and Planetary Science Letters 361, 50–57. https://doi.org/10.1016/j.epsl.2012.11.023
, 2014Roth, A.S.G., Bourdon, B., Mojzsis, S.J., Rudge, J.F., Guitreau, M., Blichert‐Toft, J. (2014) Combined 147,146Sm-143,142Nd constraints on the longevity and residence time of early terrestrial crust. Geochemistry, Geophysics, Geosystems 15, 2329–2345. https://doi.org/10.1002/2014GC005313
; 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 3.8–3.0Ga rocks from the Anshan Complex, North China Craton. Precambrian Research 301, 86–101. https://doi.org/10.1016/j.precamres.2017.09.001
; Maya et al., 2017Maya, J.M., Bhutani, R., Balakrishnan, S., Rajee Sandhya, S. (2017) Petrogenesis of 3.15 Ga old Banasandra komatiites from the Dharwar craton, India: Implications for early mantle heterogeneity. Geoscience Frontiers 8, 467–481. https://doi.org/10.1016/j.gsf.2016.03.007
; 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
; 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
; 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
; Wainwright et al., 2019Wainwright, A.N., El Atrassi, F., Debaille, V., Mattielli, N. (2019) Geochemistry and petrogenesis of Archean mafic rocks from the Amsaga area, West African craton, Mauritania. Precambrian Research 324, 208–219. https://doi.org/10.1016/j.precamres.2019.02.005
). The green line is the model from Debaille et al. (2013)Debaille, V., O’Neill, C., Brandon, A.D., Haenecour, P., Yin, Q.-Z., Mattielli, N., Treiman, A.H. (2013) Stagnant-lid tectonics in early Earth revealed by 142Nd variations in late Archean rocks. Earth and Planetary Science Letters 373, 83–92. https://doi.org/10.1016/j.epsl.2013.04.016
showing trend of mixing in the mantle required to progress from the most positive values at 3.8 Ga to the +7 found in Abitibi at 2.7 Ga.