Carbonatite Isotope Dataset (CID): A critical reappraisal of Sr, Nd, C, O isotopes and trends

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F25%3A00142402" target="_blank" >RIV/00216224:14310/25:00142402 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S001282522500234X" target="_blank" >https://www.sciencedirect.com/science/article/pii/S001282522500234X</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.earscirev.2025.105273" target="_blank" >10.1016/j.earscirev.2025.105273</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Carbonatite Isotope Dataset (CID): A critical reappraisal of Sr, Nd, C, O isotopes and trends

Popis výsledku v původním jazyce

Here we present a compilation of published Sr[sbnd]Nd and C[sbnd]O isotope data on carbonatites and phoscorites of the World integrated in the Carbonatite Isotope Dataset, covering the known interval of the carbonatite formation from recent up to ∼3 Ga ago. The dataset brings together 2545 87Sr/86Sr, 2692 143Nd/144Nd and 2528 13C/12C-18O/16O isotope ratios from a total of 319 deposits and occurrences with known ages. Measured Sr[sbnd]Nd isotope ratios have been revised, recalculated and errors fixed using a set of unified equations and normalization factors. The final data can be sorted according to chemical composition, formation age, model ages, geotectonic setting, associated silicate magma and geographic affiliations (region, state, and continent). Analysis of Sr[sbnd]Nd isotope evolution of carbonatites and phoscorites revealed gradual change from primordial depleted mantle character of parental magmas to recent HIMU-like, plume-related character modified to various extents by the assimilation of continental crust. Large perturbations of Sr[sbnd]Nd isotope compositions are coincidental with the break-up and fragmentation of Columbia and Gondwana. Theoretical examples of isotope fractionation associated with magma mixing, phenocryst accumulation, degassing, and alteration have been calculated and compared with those observed in carbonatites affiliated with mantle plumes. Most variations in the recorded C[sbnd]O isotope composition can be attributed to subsolidus alteration of primary igneous carbonatite with low-temperature aqueous fluids enriched in CO2. The low-temperature alteration combined with the igneous source heterogeneity and high-temperature magma-crust interactions obscure the stable isotope fractionation coincidental with phenocryst accumulation and magma degassing. Inverse modelling of Sr-Nd-C-O isotope trends showed that the interaction of mantle plume-derived magma with the crust may result in mixing trends with curvatures and slopes dominantly controlled by time-integrated changes in the 143Nd and 87Sr proportions, thereby modifying Sr/Nd ratios in the mixing phases. Models of mixing mantle components with similar Sr/Nd ratios, such as HIMU and EM1, also showed conspicuous, age-dependent modifications of the mixing line slope. Hence, the HIMU-EM1 trend revealed in modern carbonatites cannot be used as a template for interpreting isotopic signatures of pre-Cretaceous carbonatites. It is therefore likely that the role of enriched mantle component EM1 has been overestimated in Precambrian carbonatites at the expense of a continental crust assimilant. The same conjecture is valid for the enriched mantle component EM2, because sub-horizontal mixing trajectories with a wide range of εSrCHUR combined with limited range of εNdCHUR can also be reproduced by the contamination of mantle plume-derived magma with crustal assimilants. Except for specific carbonatites, e.g. crustal-anatectic, ocean island-related or kimberlite-associated, the Sr[sbnd]Nd and C[sbnd]O isotope ratios themselves cannot unambiguously discriminate individual genetic and geotectonic groups without additional supporting geochemical data and/or radiogenic isotope systems.

Název v anglickém jazyce

Carbonatite Isotope Dataset (CID): A critical reappraisal of Sr, Nd, C, O isotopes and trends

Popis výsledku anglicky

Here we present a compilation of published Sr[sbnd]Nd and C[sbnd]O isotope data on carbonatites and phoscorites of the World integrated in the Carbonatite Isotope Dataset, covering the known interval of the carbonatite formation from recent up to ∼3 Ga ago. The dataset brings together 2545 87Sr/86Sr, 2692 143Nd/144Nd and 2528 13C/12C-18O/16O isotope ratios from a total of 319 deposits and occurrences with known ages. Measured Sr[sbnd]Nd isotope ratios have been revised, recalculated and errors fixed using a set of unified equations and normalization factors. The final data can be sorted according to chemical composition, formation age, model ages, geotectonic setting, associated silicate magma and geographic affiliations (region, state, and continent). Analysis of Sr[sbnd]Nd isotope evolution of carbonatites and phoscorites revealed gradual change from primordial depleted mantle character of parental magmas to recent HIMU-like, plume-related character modified to various extents by the assimilation of continental crust. Large perturbations of Sr[sbnd]Nd isotope compositions are coincidental with the break-up and fragmentation of Columbia and Gondwana. Theoretical examples of isotope fractionation associated with magma mixing, phenocryst accumulation, degassing, and alteration have been calculated and compared with those observed in carbonatites affiliated with mantle plumes. Most variations in the recorded C[sbnd]O isotope composition can be attributed to subsolidus alteration of primary igneous carbonatite with low-temperature aqueous fluids enriched in CO2. The low-temperature alteration combined with the igneous source heterogeneity and high-temperature magma-crust interactions obscure the stable isotope fractionation coincidental with phenocryst accumulation and magma degassing. Inverse modelling of Sr-Nd-C-O isotope trends showed that the interaction of mantle plume-derived magma with the crust may result in mixing trends with curvatures and slopes dominantly controlled by time-integrated changes in the 143Nd and 87Sr proportions, thereby modifying Sr/Nd ratios in the mixing phases. Models of mixing mantle components with similar Sr/Nd ratios, such as HIMU and EM1, also showed conspicuous, age-dependent modifications of the mixing line slope. Hence, the HIMU-EM1 trend revealed in modern carbonatites cannot be used as a template for interpreting isotopic signatures of pre-Cretaceous carbonatites. It is therefore likely that the role of enriched mantle component EM1 has been overestimated in Precambrian carbonatites at the expense of a continental crust assimilant. The same conjecture is valid for the enriched mantle component EM2, because sub-horizontal mixing trajectories with a wide range of εSrCHUR combined with limited range of εNdCHUR can also be reproduced by the contamination of mantle plume-derived magma with crustal assimilants. Except for specific carbonatites, e.g. crustal-anatectic, ocean island-related or kimberlite-associated, the Sr[sbnd]Nd and C[sbnd]O isotope ratios themselves cannot unambiguously discriminate individual genetic and geotectonic groups without additional supporting geochemical data and/or radiogenic isotope systems.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10505 - Geology

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Earth-Science Reviews

ISSN

0012-8252

e-ISSN

1872-6828

Svazek periodika

271

Číslo periodika v rámci svazku

December

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

19

Strana od-do

105273

Kód UT WoS článku

001578851400001

EID výsledku v databázi Scopus

2-s2.0-105016197716