Elsevier

Geochimica et Cosmochimica Acta

Volume 318, 1 February 2022, Pages 388-414
Geochimica et Cosmochimica Acta

Global trends in novel stable isotopes in basalts: Theory and observations

https://doi.org/10.1016/j.gca.2021.12.008Get rights and content

Abstract

The geochemistry of global mantle melts suggests that both mid-ocean ridge basalts (MORB) and ocean island basalts (OIB) sample lithological and temperature heterogeneities originating in both the upper and lower mantle. Recently, non-traditional stable isotopes have been suggested as a new tool to complement existing tracers of mantle heterogeneity (e.g., major and trace elements, radiogenic isotopes), because mineral- and redox-specific equilibrium stable isotope fractionation effects can link the stable isotope ratios of melts to their source mineralogy and melting degree. Here, we investigate five stable isotope systems (Mg-Ca-Fe-V-Cr) that have shown promise in models or natural samples as tracers of mantle temperature and/or lithological heterogeneity. We use a quantitative model, combining thermodynamically self-consistent mantle melting and equilibrium isotope fractionation models, to explore the behaviour of the isotope ratios of these elements during melting of three mantle lithologies (peridotite, and silica-excess and silica-deficient pyroxenites), responding to changes in mantle mineralogy, oxygen fugacity, temperature and pressure. We find that, given current analytical precision, the stable isotope systems examined here are not predicted to be sensitive to mantle potential temperature variations through equilibrium isotope fractionation processes. By contrast, source lithological heterogeneity is predicted to be detectable in some cases in the stable isotope ratios of erupted basalts, although generally only at proportions of >10% MORB-like pyroxenite in the mantle source, given current analytical precision. Magnesium and Ca stable isotopes show most sensitivity to a garnet-bearing source lithology, and Fe and Cr stable isotopes are potentially sensitive to the presence of MORB-like pyroxenite in the mantle source, although the behaviour of Cr isotopes is comparatively under-constrained and requires further work to be applied with confidence to mantle melts. When comparing the magnitude and direction of predicted equilibrium isotopic fractionation of peridotite and pyroxenite melts to natural MORB and OIB data, we find that aspects of the natural data (including the mean Mg-Ca-Fe-V isotopic composition of MORB, the range of Mg-Ca isotopic compositions seen in MORB data, the mean Mg-Ca-Cr isotopic composition of OIB, and the range of Mg-V-Cr isotopic compositions in OIB data) can be matched by equilibrium isotope fractionation during partial melting of peridotite and pyroxenite sources – with pyroxenite required even for some MORB data. However, even when considering analytical uncertainty on natural sample measurements, the range in stable isotope compositions seen across the global MORB and OIB datasets suggests that kinetic isotope fractionation, or processes modifying the isotopic composition of recycled crustal material such that it is distinct from MORB, may be required to explain all the natural data. We conclude that the five stable isotope systems considered here have potential to be powerful complementary tracers to other geochemical tracers of the source lithology of erupted basalts. However, continued improvements in analytical precision in conjunction with experimental and theoretical predictions of isotopic fractionation between mantle minerals and melts are required before these novel stable isotopes can be unambiguously used to understand source heterogeneity in erupted basalts.

Introduction

A key window into Earth’s mantle is through the petrology and geochemistry of its melts, which include both mid-ocean ridge basalts (MORB) and ocean island basalts (OIB). MORB may be able to tell us about the composition and temperature of the upper mantle across multiple length scales (e.g., Allègre et al., 1984, Zindler and Hart, 1986, Mahoney et al., 1994, Agranier et al., 2005, Janney et al., 2005, Herzberg et al., 2007, Gale et al., 2013, Shorttle, 2015). Key questions about MORB-source mantle concern the various roles of temperature, crustal thickness, lithological heterogeneity, melt mixing and melt-rock reaction and the degree to which they can explain the trace, major element, and radiogenic isotope arrays of global MORB. Decades of investigation have produced a broad consensus that in the MORB-source mantle thermally-driven variations in melting degree create global signals in major and/or trace elements (Klein and Langmuir, 1987, Dalton et al., 2014, Gale et al., 2014). On a local scale MORB also show considerable isotopic and trace element variability, linked to small-scale lithological heterogeneity in the upper mantle (e.g., Zindler et al., 1984, Langmuir et al., 1986, Fornari et al., 1988, Hekinian et al., 1989, Schiano et al., 1997, Castillo et al., 2000, Waters et al., 2011, Gill et al., 2016, Liu and Liang, 2017, Jiang et al., 2021, Zhong et al., 2021). OIB also sample a heterogeneous mantle over short and long lengthscales including significant lithological heterogeneity (e.g., Cohen and O’Nions, 1982, Weaver, 1991, Chauvel et al., 1992, Kogiso et al., 2003, Sobolev et al., 2007, Jackson and Dasgupta, 2008, Dasgupta et al., 2010, Day and Hilton, 2011, Shorttle and Maclennan, 2011), elemental and isotopic heterogeneity (e.g., Zindler and Hart, 1986, Dupuy et al., 1988, Hauri and Hart, 1993, Hofmann, 1997, Hofmann, 2003, Stracke et al., 2005, Willbold and Stracke, 2006, Prytulak and Elliott, 2007, Jackson and Dasgupta, 2008, Maclennan, 2008, Dasgupta et al., 2010, Jackson et al., 2012, Mundl et al., 2017), and record large temperature variations relative to MORB (e.g., Putirka, 2005, Herzberg et al., 2007, Putirka, 2008a, Putirka, 2008b, Herzberg and Gazel, 2009, Herzberg and Asimow, 2015, Matthews et al., 2021).

In this study, we investigate the use of novel stable isotopes of major and minor elements in basalts (magnesium [δ26/24Mg], calcium [δ44/40Ca], iron [δ57/54Fe], vanadium [δ51/50V], chromium [δ53/52Cr]) as new tools for studying temperature and lithological heterogeneity in the mantle, complementary to existing work on MORB and OIB mantle sources using major and trace elements (e.g., Klein and Langmuir, 1987, Langmuir et al., 1992, McKenzie et al., 2004, Putirka, 2005, Herzberg et al., 2007, Jackson and Dasgupta, 2008, Niu and O’Hara, 2008, Dasgupta et al., 2010, Le Roux et al., 2011, Jackson et al., 2012, Lambart et al., 2013, Gale et al., 2014, Yang et al., 2019, Mallik et al., 2021). The chosen isotope systems may trace thermal and mineralogical heterogeneity in the source region of melts through their temperature and mineral-dependent equilibrium fractionation factors (e.g., Schauble, 2004, Young et al., 2015), and we include detail on the choice of these isotope systems in Section 1.3.

Mantle-derived melts, particularly MORB, show global geochemical arrays that can be explained by the conditions of melt generation in the mantle (e.g., temperature, lithology; Klein and Langmuir, 1987, Langmuir et al., 1992, Niu and O’Hara, 2008, Arevalo and McDonough, 2010, Gale et al., 2014) and/or subsequent melt transport and storage processes (e.g., melt mixing, melt-rock reaction, fractional crystallisation; Devey et al., 1994, Arevalo and McDonough, 2010, Liang et al., 2011, Kimura and Sano, 2012, Till et al., 2012, Shorttle, 2015, Bo et al., 2018, Mallik et al., 2021, Stracke, 2021). Once corrected for crystal fractionation, moderately incompatible element concentrations (e.g., Na, Al) in global MORB correlate positively with ridge depth, commonly interpreted to equate to a control by mantle potential temperature variations of around 220°C (Klein and Langmuir, 1987, Langmuir et al., 1992, Brandl et al., 2013, Gale et al., 2014). Correlations between fractionation-corrected major element compositions in MORB (e.g., FeO-Na2O, CaO-Al2O3) are consistent with the same mantle temperature variations (Langmuir et al., 1992, Gale et al., 2014). Although mantle composition has also been invoked instead of temperature variation to explain these trends (by applying a different fractionation correction; Niu and O’Hara, 2008), major element compositions measured in OIB and their constituent olivine, as well as olivine crystallisation thermometry and geophysical observations, argue in favour of there being regions of mantle up to 250°C hotter than typical mid-ocean ridge mantle (e.g., Putirka, 2005, Herzberg et al., 2007, Putirka, 2008a, Dalton et al., 2014, Herzberg and Asimow, 2015, Spice et al., 2016, Ball et al., 2021, Matthews et al., 2021).

Although temperature may be a dominant control on MORB geochemical variability, mantle compositional heterogeneity is also clear in the elemental and isotopic compositions of both MORB and OIB. For example, in MORB highly incompatible element enrichment (e.g., fractionation-corrected K concentrations) correlates roughly with radiogenic isotopes, which must relate to source heterogeneity, such as through the addition or removal of low-degree melts (e.g., McKenzie and O’Nions, 1995, Donnelly et al., 2004, Gale et al., 2011, Gale et al., 2013, Gale et al., 2014). Radiogenic and stable isotopes and trace elements have also been used to argue for the presence of incompatible trace element-enriched, recycled components in the MORB source (e.g., Hirschmann and Stolper, 1996, Schiano et al., 1997, Salters and Dick, 2002, Bezard et al., 2016). In OIB, there is extensive evidence for mantle heterogeneity in the form of radiogenic and stable isotope compositions and the concentrations of major elements in basalt and trace elements in olivine (e.g., Zindler and Hart, 1986, Weaver, 1991, Hauri, 1996, Hofmann, 1997, Sobolev et al., 2005, Stracke et al., 2005, Sobolev et al., 2007, Jackson and Dasgupta, 2008, Day et al., 2009, Herzberg, 2011, Shorttle and Maclennan, 2011, Konter et al., 2016, Mundl et al., 2017, Neave et al., 2018, Nebel et al., 2019, Gleeson et al., 2020). This mantle heterogeneity is thought to relate largely to the recycling of crust, and the reaction between recycled lithologies (and their melts) and ambient mantle peridotite (e.g., Cohen and O’Nions, 1982, Hofmann and White, 1982, Allègre and Turcotte, 1986, Schiano et al., 1997, Sobolev et al., 2005, Sobolev et al., 2007, Herzberg, 2011, Mallik and Dasgupta, 2012, Stracke, 2012, Rosenthal et al., 2014, Lambart, 2017).

Many tools are available to study the contributions of temperature and lithological heterogeneity in these two types of basalts, for example: rare earth element inversion modelling (INVMEL: McKenzie and O’Nions, 1991, McKenzie and O’Nions, 1995), major element calculations (PRIMELT: Herzberg and Asimow, 2008, Herzberg and Asimow, 2015; the thermodynamic model of Jennings and Holland, 2015, Jennings et al., 2016), trace element and radiogenic isotope composition forward modelling (REEBOX PRO: Brown and Lesher, 2016), and models combining trace elements, crystallisation temperatures and magma productivity (Shorttle et al., 2014, Matthews et al., 2016, Matthews et al., 2021). However, achieving success in linking the elemental and radiogenic isotope variability in MORB and OIB to temperature and/or lithological heterogeneity is complicated by uncertainty in the nature of enriched lithologies, metasomatism by small volumes of melt (which are usually highly enriched in incompatible elements, so can overwhelm evidence of the original source lithology), magma recharge and mixing, diffusional re-equilibration and fractional crystallisation (e.g., Niu and O’Hara, 2003, Workman et al., 2004, Niu and O’Hara, 2008, Lambart et al., 2013, Matzen et al., 2017, Gleeson and Gibson, 2019). Stable isotopes of major and minor elements complement radiogenic isotopes and major element calculations and could provide new constraints on understanding global basalt chemistry: stable isotope systems are time-independent, and since their equilibrium partitioning is a function of mineral chemistry, they are the natural extension of major element calculations based on thermodynamic data. In addition, some of these stable isotopes are major elements whose budgets in the mantle source and subsequent erupted melts reflect contributions from both enriched and depleted lithologies, and are not dominated by small-degree melt metasomatism.

Stable isotopes may trace thermal and mineralogical heterogeneity in the mantle through their temperature and mineral-dependent equilibrium fractionation factors (e.g., Schauble, 2004, Young et al., 2015). Our understanding of the equilibrium high temperature fractionation effects experienced by novel stable isotope systems is improving, and many studies (both theoretical and from natural samples) suggest controls from mantle temperature and lithology on the isotopic composition of the melts produced. Previous studies have shown considerable variability in stable isotope ratios in MORB and OIB even where the geochemical signals of fractional crystallisation are considered to be negligible, or have been removed (Fig. 1), but understanding the origin of the variability remains challenging. For example, Fig. 1 shows that natural basalt stable isotope data for the isotope systems considered here have different systematics relative to the bulk silicate Earth (BSE). Magnesium and V stable isotope compositions in MORB and OIB scatter both sides of the BSE value, whereas Fe stable isotope compositions of basalts are heavier than the BSE, and for Cr and Ca basalts are (mostly) isotopically lighter than the BSE. The Mg and Fe stable isotope compositions of OIB show greater variability than MORB for the same isotope system, whereas the opposite is true for V stable isotopes (although this may be a sampling bias, given the greater amount of V isotope data for MORB than OIB).

Modelling of expected stable isotopic behaviour has led to questions about the origin of isotopic signatures observed in natural samples. For example, some studies have modelled Ca stable isotope fractionation using composition-dependent inter-mineral fractionation factors and concluded that partial melting of eclogite cannot produce the variability measured in OIB (Chen et al., 2020a), whereas others have predicted and measured that garnet has a higher δ44Ca than coexisting clinopyroxene (Antonelli et al., 2019, Huang et al., 2019, Kang et al., 2019, Wang et al., 2019, Chen et al., 2020a, Dai et al., 2020, Smart et al., 2021, Tappe et al., 2021), and have used this observation to predict that melts from recycled oceanic crust (garnet-bearing eclogite) will have low δ44Ca, thus explaining the low δ44Ca measured in some OIB (Kang et al., 2019, Dai et al., 2020). Lithological heterogeneity (specifically, recycled pyroxenite) has also been linked to Mg and Fe isotope variability in MORB and OIB (e.g., Williams and Bizimis, 2014, Konter et al., 2016, Zhong et al., 2017, Stracke et al., 2018, Nebel et al., 2019, Gleeson et al., 2020, Sun et al., 2020, Zhong et al., 2021). However, some recent models of Fe and Mg isotope fractionation have led to uncertainty in whether equilibrium fractionation associated with the presence of garnet can unambiguously identify a garnet-bearing pyroxenite source lithology in natural OIB samples (Soderman et al., 2021, Stracke et al., 2018), and whether the heaviest Fe isotope data in the global dataset can be matched by models of mantle melting (Soderman et al., 2021, Sun et al., 2020).

Given the framework of MORB and OIB data that we now have (Fig. 1), growing theoretical information on bond strength and predicted inter-mineral fractionations for multiple stable isotope systems, and a variety of published isotope fractionation models that both can and cannot explain all the natural data, it is timely to develop a self-consistent model for the behaviour of multiple stable isotopes during mantle melting. Here we use a thermodynamically self-consistent model for mantle melting of three lithologies (peridotite and two different pyroxenites), combined with a model for equilibrium Mg-Ca-Fe-V-Cr stable isotope fractionation responding to changes in mantle mineralogy, intrinsic variations in oxygen fugacity (i.e., at constant O content), temperature and pressure. These models allow us to investigate the potential for the stable isotope composition of basalts to be a tracer of mantle temperature and lithological heterogeneity.

This contribution explores the behaviour of Mg-Ca-Fe-V-Cr stable isotopes during mantle melting, expanding on work on Fe stable isotope behaviour presented in Soderman et al. (2021). These isotope systems were chosen as they have been documented to show resolvable mineral-specific fractionation effects that may make them sensitive to partial melting or source lithology effects (e.g., Konter et al., 2016, Xia et al., 2017, Stracke et al., 2018, Wu et al., 2018, Kang et al., 2019, Nebel et al., 2019, Dai et al., 2020, Gleeson et al., 2020, Shen et al., 2020, Novella et al., 2020), and their bonding environments and/or expected isotopic fractionation in mantle minerals and melt are sufficiently well-studied to provide reasonable inputs for an isotopic fractionation model. The isotope systems represent both major and trace elements in basalts, and monovalent and heterovalent elements. The major elements (Mg, Ca, Fe) are abundant in the mantle with comparable or lower concentrations in pelitic sediments and crustal material (Plank and Langmuir, 1998, Rudnick and Gao, 2003, Workman and Hart, 2005), meaning the isotopic signatures of mantle components are not easily affected by metasomatism, and their isotopic compositions in basalts should track the bulk mass contributions of both fertile and depleted mantle lithologies to the melt. This is an important property of major element stable isotope systems that contrasts with radiogenic isotope systems of incompatible trace elements, which cannot probe the proportions of different lithologies directly, as incompatible element concentrations vary widely between enriched and depleted mantle lithologies. We note that carbonates, whose presence have been invoked in the source regions of mantle melts (e.g., Huang et al., 2011b, Liu et al., 2017a, Wang et al., 2018), have Ca concentrations 10 times higher than the mantle (e.g., Huang et al., 2011b), but we do not discuss carbonates here; instead we filter natural data used in this study by 87Sr/86Sr to exclude significant contributions from carbonate components.

Section 2 contains a description of the combined thermodynamic melting and equilibrium isotope fractionation model. The model was used to calculate the equilibrium isotopic composition of mantle melts from different lithologies over P-T space, and a summary of the results is presented in this section.

Sections 3 Stable isotope sensitivity to mantle temperature variations, 4 Lithological heterogeneity address the degree to which different stable isotope measurements (individual isotope systems, or in combination) can identify the relative importance of mantle temperature variability and mantle lithological heterogeneity in generating the observed variability in basalts. We also discuss where stable isotope systems have the potential to be useful in identifying these processes, if measurement uncertainties can be reduced.

Finally, Section 5 combines MORB and OIB data for the isotope systems studied with the modelled equilibrium melts, to assess to what extent our present understanding of the isotope behaviour can explain global basalt variability. We do not include arc basalts in our discussion for a number of reasons, including but not limited to the complicating effects of H2O, slab fluids and redox variability in an arc setting, which have been linked to stable Fe and Mg isotope variability recorded in arc basalts (e.g., Dauphas et al., 2009, Nebel et al., 2013, Nebel et al., 2015, Sossi et al., 2016, Teng et al., 2016, Li et al., 2017, Brewer et al., 2018, Hu et al., 2020) and which are beyond the applicable scope of the modelling presented here.

Section snippets

Modelling equilibrium isotopic composition of mantle melts

We calculated the equilibrium melting isotopic fractionation over P-T space for δ26/24Mg, δ44/40Ca, δ57/54Fe, δ51/50V and δ53/52Cr for three representative mantle lithologies, following the model outlined in Soderman et al. (2021). We used the calculated modal mineralogies over P-T space of KLB1 peridotite (a commonly used experimental composition used as an analogue for the upper mantle; Davis et al., 2009) and G2 silica-excess pyroxenite (an important MORB-like bulk composition in melting

Stable isotope sensitivity to mantle temperature variations

To explore the sensitivity of stable isotopes in basalts to variations in mantle potential temperature, we use the results of the equilibrium melt fractionation model for KLB1, since for MORB, the dominant source lithology is peridotite (Hirschmann and Stolper, 1996, Sobolev et al., 2007). Generally, all equilibrium source-melt isotopic fractionations are expected to decrease in magnitude with increased temperature (e.g., Bigeleisen and Mayer, 1947), although this effect will be small at high

Lithological heterogeneity

We next investigate the use of stable isotopes as tracers of lithological heterogeneity in the mantle, using two pyroxenite lithologies, MIX1G (silica deficient, SD pyroxenite) and G2 (silica excess, SE pyroxenite). Silica-deficient pyroxenites may be the most representative type of pyroxenites found in the convecting mantle (the majority of pyroxenite xenoliths sampled in OIB are SD; Lambart et al. (2016) – natural SD pyroxenites are considered to be formed by metasomatism of peridotite by

Comparisons to natural data

Fig. 8 shows how literature MORB and OIB data compare to modelled melts. The modelled melts are filtered for those produced at cooler temperatures than the Tp = 1530°C peridotite isentrope for a given pressure, to limit the contribution of unrealistic high melt fraction and high pressure melts. The same potential temperature isentrope has been chosen for all lithologies for consistency, although because of its fusibility this filter includes some 100% melts of G2 at all pressures. Natural

Summary

We have combined a thermodynamically self-consistent model for mantle melting of peridotite and pyroxenite with a model for equilibrium Mg-Ca-Fe-V-Cr stable isotope fractionation to quantitatively predict melt-source stable isotope fractionation over P-T conditions relevant to mantle melting at mid-ocean ridges and within mantle plumes. The results allow us to assess the potential of these stable isotope systems for investigating mantle temperature variations, source heterogeneity, and their

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

We thank Andreas Stracke, Michael Antonelli and an anonymous reviewer whose comments greatly improved this manuscript, and Stefan Weyer for editorial handling. C. R. S. also thanks William Miller for valuable discussions throughout this project, Tim Holland for support with thermocalc, and Michael Carpenter and Ross Angel for helpful guidance regarding ionic bonding models. This work was supported by a NERC Studentship NE/L002507/1 to C.R.S., and ERC Consolidator Grant 306655 ‘HabitablePlanet’,

References (228)

  • D. Canil

    Vanadium partitioning between orthopyroxene, spinel and silicate melt and the redox states of mantle source regions for primary magmas

    Geochim. Cosmochim. Acta

    (1999)
  • C. Chauvel et al.

    HIMU-EM: the French Polynesian connection

    Earth Planet. Sci. Lett.

    (1992)
  • C. Chen et al.

    Calcium isotopic compositions of oceanic crust at various spreading rates

    Geochim. Cosmochim. Acta

    (2020)
  • C. Chen et al.

    Calcium isotope fractionation during magmatic processes in the upper mantle

    Geochim. Cosmochim. Acta

    (2019)
  • C. Chen et al.

    Compositional and pressure controls on calcium and magnesium isotope fractionation in magmatic systems

    Geochim. Cosmochim. Acta

    (2020)
  • S. Chen et al.

    Iron isotope fractionation during mid-ocean ridge basalt (MORB) evolution: Evidence from lavas on the East Pacific Rise at 10°30’ N and its implications

    Geochim. Cosmochim. Acta

    (2019)
  • R.S. Cohen et al.

    Identification of recycled continental material in the mantle from Sr, Nd and Pb isotope investigations

    Earth Planet. Sci. Lett.

    (1982)
  • W. Dai et al.

    Calcium isotope compositions of mantle pyroxenites

    Geochim. Cosmochim. Acta

    (2020)
  • R. Dasgupta et al.

    Major element chemistry of ocean island basalts—Conditions of mantle melting and heterogeneity of mantle source

    Earth Planet. Sci. Lett.

    (2010)
  • N. Dauphas et al.

    Iron isotopes may reveal the redox conditions of mantle melting from Archean to Present

    Earth Planet. Sci. Lett.

    (2009)
  • N. Dauphas et al.

    Magnesium and iron isotopes in 2.7 Ga Alexo komatiites: mantle signatures, no evidence for Soret diffusion, and identification of diffusive transport in zoned olivine

    Geochim. Cosmochim. Acta

    (2010)
  • F.A. Davis et al.

    Experimentally determined mineral/melt partitioning of first-row transition elements (FRTE) during partial melting of peridotite at 3 GPa

    Geochim. Cosmochim. Acta

    (2013)
  • J.M.D. Day et al.

    Origin of 3He/4He ratios in HIMU-type basalts constrained from Canary Island lavas

    Earth Planet. Sci. Lett.

    (2011)
  • X. Ding et al.

    Vanadium isotope fractionation during differentiation of Kilauea Iki lava lake, Hawaii

    Geochim. Cosmochim. Acta

    (2020)
  • K.E. Donnelly et al.

    Origin of enriched ocean ridge basalts and implications for mantle dynamics

    Earth Planet. Sci. Lett.

    (2004)
  • M.S. Fantle et al.

    Variations in the marine Ca cycle over the past 20 million years

    Earth Planet. Sci. Lett.

    (2005)
  • J. Farkaš et al.

    Chromium isotope variations (δ53/52Cr) in mantle-derived sources and their weathering products: Implications for environmental studies and the evolution of δ53/52Cr in the Earth’s mantle over geologic time

    Geochim. Cosmochim. Acta

    (2013)
  • C. Feng et al.

    First-principles investigations of equilibrium calcium isotope fractionation between clinopyroxene and Ca-doped orthopyroxene

    Geochim. Cosmochim. Acta

    (2014)
  • A. Gale et al.

    Constraints on melting processes and plume-ridge interaction from comprehensive study of the FAMOUS and North Famous segments, Mid-Atlantic Ridge

    Earth Planet. Sci. Lett.

    (2013)
  • M.L.M. Gleeson et al.

    Novel insights from Fe-isotopes into the lithological heterogeneity of Ocean Island Basalts and plume-influenced MORBs

    Earth Planet. Sci. Lett.

    (2020)
  • T. Hanyu et al.

    Isotope evolution in the HIMU reservoir beneath St. Helena: Implications for the mantle recycling of U and Th

    Geochim. Cosmochim. Acta

    (2014)
  • E.H. Hauri et al.

    ReOs isotope systematics of HIMU and EMII oceanic island basalts from the south Pacific Ocean

    Earth Planet. Sci. Lett.

    (1993)
  • M.M. Hirschmann et al.

    Storage capacity of H2O in nominally anhydrous minerals in the upper mantle

    Earth Planet. Sci. Lett.

    (2005)
  • G. Hirth et al.

    Water in the oceanic upper mantle: implications for rheology, melt extraction and the evolution of the lithosphere

    Earth Planet. Sci. Lett.

    (1996)
  • A.W. Hofmann et al.

    Mantle plumes from ancient oceanic crust

    Earth Planet. Sci. Lett.

    (1982)
  • Y. Hu et al.

    Magnesium isotopic composition of metasomatized upper sub-arc mantle and its implications to Mg cycling in subduction zones

    Geochim. Cosmochim. Acta

    (2020)
  • F. Huang et al.

    First-principles calculations of equilibrium Mg isotope fractionations between garnet, clinopyroxene, orthopyroxene, and olivine: implications for Mg isotope thermometry

    Earth Planet. Sci. Lett.

    (2013)
  • F. Huang et al.

    Iron and magnesium isotopic compositions of peridotite xenoliths from Eastern China

    Geochim. Cosmochim. Acta

    (2011)
  • F. Huang et al.

    First-principles calculations of equilibrium Ca isotope fractionation: Implications for oldhamite formation and evolution of lunar magma ocean

    Earth Planet. Sci. Lett.

    (2019)
  • J. Huang et al.

    Magnesium isotopic compositions of altered oceanic basalts and gabbros from IODP site 1256 at the East Pacific Rise

    Lithos

    (2015)
  • S. Huang et al.

    Stable calcium isotopic compositions of Hawaiian shield lavas: evidence for recycling of ancient marine carbonates into the mantle

    Geochim. Cosmochim. Acta

    (2011)
  • D.A. Ionov et al.

    Calcium isotopic signatures of carbonatite and silicate metasomatism, melt percolation and crustal recycling in the lithospheric mantle

    Geochim. Cosmochim. Acta

    (2019)
  • M.G. Jackson et al.

    Compositions of HIMU, EM1, and EM2 from global trends between radiogenic isotopes and major elements in ocean island basalts

    Earth Planet. Sci. Lett.

    (2008)
  • M. Jerram et al.

    The δ53Cr isotope composition of komatiite flows and implications for the composition of the bulk silicate Earth

    Chem. Geol.

    (2020)
  • Q. Jiang et al.

    Origin of geochemically heterogeneous mid-ocean ridge basalts from the Macquarie Ridge Complex, SW Pacific

    Lithos

    (2021)
  • J.-T. Kang et al.

    Calcium isotopic fractionation in mantle peridotites by melting and metasomatism and Ca isotope composition of the Bulk Silicate Earth

    Earth Planet. Sci. Lett.

    (2017)
  • J.-T. Kang et al.

    Calcium isotope sources and fractionation during melt-rock interaction in the lithospheric mantle: Evidence from pyroxenites, wehrlites, and eclogites

    Chem. Geol.

    (2019)
  • J.-T. Kang et al.

    Diffusion-driven Ca-Fe isotope fractionations in the upper mantle: Implications for mantle cooling and melt infiltration

    Geochim. Cosmochim. Acta

    (2020)
  • T. Kogiso et al.

    High-pressure partial melting of garnet pyroxenite: possible mafic lithologies in the source of ocean island basalts

    Earth Planet. Sci. Lett.

    (2003)
  • C.J. Allègre et al.

    Implications of a two-component marble-cake mantle

    Nature

    (1986)
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    Present address: Institute of Earth Sciences, University of Iceland, Iceland.

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