The effects of high-temperature fractional crystallization on calcium isotopic composition

Valdes, Maria C.; Debaille, Vinciane; Berger, Julien; Armytage, R. M. G.

doi:10.1016/j.chemgeo.2019.01.012

Cited by 24 publications

(7 citation statements)

References 67 publications

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“…In addition, the influence of Cpx accumulation has been largely exaggerated by assuming all the CaO removal was attributed to the fractional crystallization of Cpx. In conclusion, although the fractional crystallization of Ca-rich phases (e.g., Pl and Cpx) could generate measurable δ 44/40 Ca variations in some cases (Valdes et al, 2019;Zhu et al, 2021),…”

Section: Fractional Crystallizationmentioning

confidence: 86%

“…The whole rock samples of the Lutao arc volcanics present LOI values of < 2 wt.%, suggesting the secondary alteration is quite limited. Limited secondary alteration is also testified by lacking Ce anomalies (Ce/Ce* in the Lutao volcanics, 0.96 -1.02) and significant correlations between Sm, Sr, and Nd (Polat and Hofmann, 2003;Valdes et al, 2019). The correlation between LOI and δ 44/40 Ca values is not significant, indicating secondary alteration has placed negligible influence on the Ca isotopic characteristics of Lutao arc magmas (Fig.…”

Section: Negligible Influence Of Secondary Alterationmentioning

confidence: 96%

“…The arc magmas may have been secondary altered by seawater or hydrothermal fluids. Because chemical weathering and/or fluid alteration on the igneous rocks would result in the hydration of glasses and formation of hydrous minerals, LOI is an essential indicator of the alteration degree (Banerjee and Chakrabarti, 2018 (John et al, 2012;Blättler and Higgins, 2017;Valdes et al, 2019;Chen et al, 2020a).…”

Section: Negligible Influence Of Secondary Alterationmentioning

confidence: 99%

“…The TFe2O3 and TiO2 contents with decreasing MgO could be satisfied by the fractional accumulation of Heavier Ca isotopes are enriched in phases with shorter bonds and smaller coordination numbers (Chacko et al, 2001;Huang et al, 2010Feng et al, 2014). As a result, Opx and Ol, which possess shorter Ca-O bonds, are isotopically heavier in Ca than co-existing Cpx (Huang et al, 2010;Kang et al, 2016Chen et al, 2019;Valdes et al, 2019), while Hbl and Pl are enriched in lighter Ca isotopes with respect to Ol and pyroxenes Valdes et al, 2019). However, the fractional crystallization of Ol and Opx could not significantly change the δ 44/40 Ca values of the residual magma, due to their extremely low CaO contents with respect to Cpx, Hbl, and Pl (Zhang et al, 2018;Chen et al, 2019).…”

Section: Fractional Crystallizationmentioning

confidence: 99%

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Recycling of Marine Carbonate Induced Calcium Isotope Heterogeneity of Arc Magmas in Subduction Zones

Chen¹,

Wu²,

Gao³

et al. 2021

Preprint

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Calcium (Ca) is an essential element constituting sedimentary carbonate in subducting sediments. Ca isotopic characteristics of subduction-related rocks could provide insight into the behavior and budget of carbonate and carbon cycles in subduction zones, due to the distinctive δ44/40Ca ranges of sedimentary carbonate with respect to the mantle. Here, we studied the Ca isotopic compositions of arc magmas from the Northern Luzon arc (NLA), which are evolved from a depleted mantle metasomatized by slab-derived fluids and sediment melts. The δ44/40Ca values range from 0.76 ± 0.04&permil; to 1.01 ± 0.03&permil; and cover the typical ranges for bulk silica earth (BSE, ~ 0.94&permil;) and fresh mid-ocean ridge basalt (MORB, ~ 0.83&permil;). The Ca isotopes of NLA volcanics are not dominantly determined by the effects of mantle partial melting or fractional crystallization, nor significantly modified by secondary alteration. Instead, the δ44/40Ca values of NLA volcanics are controlled by the subduction-related metasomatism. The metasomatism by slab-derived fluids (mainly expelled from altered oceanic crust, AOC) dramatically elevated the contents of fluid-mobile elements (e.g., Ba and Pb) with respect to fluid-immobile elements (e.g., Ce). This process, however, rarely modified the Ca isotopes, possibly ascribed to the δ44/40Ca similarity between AOC and the depleted mantle. The δ44/40Ca values significantly correlated with subduction indicators (e.g., Sr-Nd isotopes, Ba/Nb, Ce/Pb, and Nb/La), demonstrating the Ca isotopes of NLA volcanics are mainly controlled by the metasomatism of sediment melts subducting from the South China Sea (SCS). Based on the thermal structures and chemical compositions of sediments subducting into global trenches, we propose that carbonate Ca isotopic signals can only be observed in the arcs with high sedimentary Ca fluxes and temperature-pressure conditions well beyond the solidus of H2O-saturated sediment melting, e.g., NLA, Nicaragua, Guatemala, Colombia, Peru, South Chile, North Vanuatu, New Zealand, and Kermadec. The absence of such signals in other arcs suggests either limited sedimentary fluxes or much of the subducting sedimentary carbonate has been survived during plate subduction to enter the deep mantle.

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Section: Fractional Crystallizationmentioning

confidence: 86%

Section: Negligible Influence Of Secondary Alterationmentioning

confidence: 96%

Section: Negligible Influence Of Secondary Alterationmentioning

confidence: 99%

Section: Fractional Crystallizationmentioning

confidence: 99%

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Recycling of Marine Carbonate Induced Calcium Isotope Heterogeneity of Arc Magmas in Subduction Zones

Chen¹,

Wu²,

Gao³

et al. 2021

Preprint

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“…Isotopic mass dependent fractionations are generated by physical (e.g., diffusion, adsorption), chemical (e.g., precipitation, redox change) or biological processes. Involvement of such a wide range of processes has made stable isotope geochemistry a powerful tool in studying synthetic and natural systems, spanning environmental pollution [12,13], to (paleo)climatology [14], ecology [15], petrogenesis [16,17], Solar System formation [10,[18][19][20] etc.…”

Section: Introductionmentioning

confidence: 99%

Cerium stable isotope analysis of synthetic and terrestrial rock reference materials by MC-ICPMS

Pourkhorsandi

Debaille

Jong

et al. 2021

Talanta

Self Cite

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Cerium is the most abundant rare earth element (REE) in the solar photosphere, CI chondrites, and the Earth. It has four main stable isotopes (masses: 136,138,140, and 142), with 138 Ce being the most studied species, used in geochronology and petrogenesis. In addition, more abundant 140 Ce and 142 Ce are suggested to be potentially applicable in geochemical investigations. In this work, we developed a modified four-step ion chromatography procedure for Ce chemical separation. Using a MC-ICPMS, we designed a cup configuration to measure 142 Ce/ 140 Ce ratio of the samples with an optimized Nd correction equation. A 0.03‰ (2SD) reproducibility was obtained for Ce Ames metal standard. We analyzed ten different igneous and one sedimentary geochemical reference materials. Mean δ 142 Ce range from −0.07 to 0.32‰. Most of the samples show a heavier Ce isotopic composition than the Ce Ames standard. The majority of rocks have a homogenous δ 142 Ce. The δ 142 Ce does not show any correlation with rock chemical composition including their Ce content or rock types. A carbonatite (SARM 40) has a mean δ 142 Ce of −0.07 ± 0.13‰ (2SD), lower than the other rocks, suggesting the possibility of a pronounced isotopic fractionation. Our work demonstrates the applicability of the developed methodology and the potential of Ce stable isotopes for future geochemical studies. Production of a larger database of δ 142 Ce values is required to obtain a clearer view on the similarities and differences between different geological material and explaining Ce stable isotope dynamics.

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Isotope Fractionation Processes of Selected Elements

Hoefs¹

2021

Springer Textbooks in Earth Sciences, Geography and Environment

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The effects of high-temperature fractional crystallization on calcium isotopic composition

Cited by 24 publications

References 67 publications

Recycling of Marine Carbonate Induced Calcium Isotope Heterogeneity of Arc Magmas in Subduction Zones

Recycling of Marine Carbonate Induced Calcium Isotope Heterogeneity of Arc Magmas in Subduction Zones

Cerium stable isotope analysis of synthetic and terrestrial rock reference materials by MC-ICPMS

Isotope Fractionation Processes of Selected Elements

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