Spinel–olivine magnesium isotope thermometry in the mantle and implications for the Mg isotopic composition of Earth
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Ultra-depleted, shallow cratonic mantle beneath West Greenland: dunitic xenoliths from Ubekendt Ejland
Dunitic xenoliths from late Palaeogene, alkaline basalt flows on Ubekendt Ejland, West Greenland contain olivine with 100 · Mg/(Mg + Fe), or Mg#, between 92.0 and 93.7. Orthopyroxene has very low Al2O3 and CaO contents (0.024–1.639 and 0.062–0.275 wt%, respectively). Spinel has 100 · Cr/ (Cr + Al), or Cr#, between 46.98 and 95.67. Clinopyroxene is absent. The osmium isotopic composition of oliv...
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The Mg isotopic compositions of olivine, spinel, and hihonite from the Murchison carbonaceous chondrite have been determined by secondary ion mass spectrometry. The olivines exhibit only marginal effects. They have no detectable intrinsic mass fractionation; however, after correcting for mass fractionation, the mean residual 26Mg/24Mg for the five grams is slightly in excess of the terrestrial ...
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تاریخ انتشار 2009