Processes and time scales of magmatic evolution as revealed by Fe–Mg chemical and isotopic zoning in natural olivines

Oeser, Martin; Dohmen, Ralf; Horn, I.; Schuth, Stephan; Weyer, Stefan

doi:10.1016/j.gca.2015.01.025

Cited by 107 publications

(96 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Diffusion first lowers the Fo content of the rims while leaving the core unaffected. No isotope fractionation is observed in the core at this stage (Fig 5;Oeser et al, 2015;Richter et al, 2016). As the olivine crystal continues to equilibrate, Fe-Mg isotope fractionation progressively reaches the core.…”

Section: Origin Of the Chemical Zoning In Olivine Megacrysts Of Nwa 1068mentioning

confidence: 91%

“…Fe and Mg isotope ratios were measured in situ using the same laser ablation system but connected to a ThermoFinnigan Neptune multicollector ICP-MS (MC-ICP-MS) operated in a high mass resolution mode (Weyer and Schwieters, 2003) with sample-standard bracketing following the exact procedure described in Oeser et al (2014Oeser et al ( , 2015. Analyzing simultaneously the 60 Ni/ 58 Ni ratio of a Ni standard solution (NIST SRM 986) with the ablation aerosol allowed to monitor the instrumental mass bias for Fe isotopes (Poitrasson and Freydier, 2005).…”

Section: Methodsmentioning

confidence: 99%

“…The exponent b is 0.5 in a gas but is known to be smaller in olivine crystals and in the range 0.08-0.16 for Mg and 0.16-0.27 for Fe (Sio et al, 2013;Oeser et al, 2015). Results from Oeser et al The initial composition of the olivine crystal is homogeneous (i.e.…”

Section: Simple Diffusion and Crystallization Modelsmentioning

confidence: 98%

“…5). As heavy isotopes diffuse slightly slower than the light ones (Jambon, 1980;Richter et al, 1999), the inward replacement of Mg by Fe (decrease in Fo content) also enriches the olivine crystals in 26 Mg (Teng et al, 2011;Sio et al, 2013;Oeser et al, 2015). Diffusion first lowers the Fo content of the rims while leaving the core unaffected.…”

Section: Origin Of the Chemical Zoning In Olivine Megacrysts Of Nwa 1068mentioning

confidence: 99%

“…Recent data on Fe and Mg isotopes in olivine have revealed that diffusive isotope fractionation can exceed equilibrium isotope fractionation at magmatic temperatures (>1000°C) by an order of magnitude (Dauphas et al, 2010;Teng et al, 2011;Weyer and Seitz, 2012;Sio et al, 2013;Oeser et al, 2015;Sio and Dauphas, 2016). Accordingly, Fe-Mg element zoning in olivine when coupled with Fe-Mg isotopic zoning allows distinguishing between chemical zoning produced by crystal growth and diffusion and to constrain cooling rates more reliably (Teng et al, 2011;Sio et al, 2013;Oeser et al, 2015;Richter et al, 2016;Sio and Dauphas, 2016).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Crystallization history of enriched shergottites from Fe and Mg isotope fractionation in olivine megacrysts

Collinet

Charlier

Namur

et al. 2017

Geochimica et Cosmochimica Acta

Self Cite

View full text Add to dashboard Cite

Martian meteorites are the only samples available from the surface of Mars. Among them, olivine-phyric shergottites are basalts containing large zoned olivine crystals with highly magnesian cores 26 Mg = À0.27 ± 0.04‰). The flat forsterite profiles of megacryst cores associated with anti-correlated fractionation of Fe-Mg isotopes indicate that these elements have been rehomogenized by diffusion at high temperature. We present a 1-D model of simultaneous diffusion and crystal growth that reproduces the observed element and isotope profiles. The simulation results suggest that the cooling rate during megacryst core crystallization was slow (43 ± 21°C/year), and consistent with pooling in a deep crustal magma chamber. The megacryst rims then crystallized 1-2 orders of magnitude faster during magma transport toward the shallower site of final emplacement. Megacryst cores had a forsterite content 3.2 ± 1.5 mol% higher than their current composition and some were in equilibrium with the whole-rock composition of NWA 1068 (Fo 80 ± 1.5). NWA 1068 composition is thus close to a primary melt (i.e. in equilibrium with the mantle) from which other enriched shergottites derived.

show abstract

Section: Origin Of the Chemical Zoning In Olivine Megacrysts Of Nwa 1068mentioning

confidence: 91%

Section: Methodsmentioning

confidence: 99%

Section: Simple Diffusion and Crystallization Modelsmentioning

confidence: 98%

Section: Origin Of the Chemical Zoning In Olivine Megacrysts Of Nwa 1068mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Crystallization history of enriched shergottites from Fe and Mg isotope fractionation in olivine megacrysts

Collinet

Charlier

Namur

et al. 2017

Geochimica et Cosmochimica Acta

Self Cite

View full text Add to dashboard Cite

show abstract

Effects of Melt Percolation on Zn Isotope Heterogeneity in the Mantle: Constraints From Peridotite Massifs in Ivrea‐Verbano Zone, Italian Alps

et al. 2018

View full text Add to dashboard Cite

We determined Zn isotopic compositions of 21 orogenic peridotites from the Baldissero and Balmuccia peridotite massifs in Ivrea‐Verbano Zone, Italian Alps, to investigate Zn isotope behaviors during partial melting and melt percolation in the mantle. The samples include lherzolites, harzburgites, and dunites. Lherzolites are strongly depleted in light rare earth element relative to middle and heavy rare earth element with (La/Sm)PM from 0.009 to 0.265 and (La/Yb)PM from 0.003 to 0.125, which can be explained by 5–15% fractional melting of a primitive mantle source. Harzburgites and dunites with nearly identical Mg# (molar 100 * Mg/(Mg + Fe) = 90.2–91.0) have (La/Sm)PM and (La/Yb)PM higher than but Zn contents similar to or lower than those of the parental lherzolites, suggesting that they were influenced by Zn‐depleted silicate melt percolation. Lherzolites have δ66Zn from 0.13 to 0.27‰ showing no correlations with indicators of melt extraction (e.g., Al2O3, Mg#, and La/Yb) and Zn contents. Three sulfide melt‐affected lherzolites show similar δ66Zn to the other normal ones. These observations indicate that 5–15% partial melting and sulfide melt percolation cause limited Zn isotope variations in the mantle. The metasomatic harzburgites and dunites display high δ66Zn (up to 0.46‰) negatively correlated with Zn contents. Such correlations are attributed to kinetic effect during silicate melt percolation, whereby 64Zn preferentially diffuses out from mantle minerals (e.g., olivine) to the percolating silicate melts. A diffusion model suggests that the negative correlation between δ66Zn and Zn contents in dunites can be explained by an empirical βZn (i.e., βZn‐exponent in D66Zn/D64Zn = (m64Zn/m66Zn)βZn) of 0.05–0.06 in olivine.

show abstract

Oxidation State, Coordination, and Covalency Controls on Iron Isotopic Fractionation in Earth's Mantle and Crust

Blanchard

Dauphas

2021

Magma Redox Geochemistry

View full text Add to dashboard Cite

Processes and time scales of magmatic evolution as revealed by Fe–Mg chemical and isotopic zoning in natural olivines

Cited by 107 publications

References 65 publications

Crystallization history of enriched shergottites from Fe and Mg isotope fractionation in olivine megacrysts

Crystallization history of enriched shergottites from Fe and Mg isotope fractionation in olivine megacrysts

Effects of Melt Percolation on Zn Isotope Heterogeneity in the Mantle: Constraints From Peridotite Massifs in Ivrea‐Verbano Zone, Italian Alps

Oxidation State, Coordination, and Covalency Controls on Iron Isotopic Fractionation in Earth's Mantle and Crust

Contact Info

Product

Resources

About