We report the first natural occurrence of the Fe-analogue of akimotoite, ilmenite-structured MgSiO3, a missing phase among the predicted high-pressure polymorphs of Fe-pyroxene, with the composition (Fe2+ 0.48Mg0.37Ca0.04Na0.04Mn2+ 0.03Al0.03Cr3+ 0.01)Σ=1.00Si1.00O3. The new mineral was approved by the International Mineralogical Association (IMA 2016-085) and named hemleyite in honour of Russell J. Hemley. It was discovered in an unmelted portion of the heavily shocked L6 Suizhou chondrite closely associated to olivine, clinoenstatite and Fe-bearing pyroxene with a composition nearly identical to that of hemleyite. We also report the first single-crystal X-ray diffraction study of a Si-bearing, ilmenitestructured phase. The fact that hemleyite formed in a meteorite exposed to high pressures (<20 GPa) and temperatures (<2000 °C) during impact-induced shocks indicates that it could play a crucial role at the bottom of the Earth’s mantle transition zone and within the uppermost lower mantle.
Discovery of the Fe-analogue of akimotoite in the shocked Suizhou L6 chondrite / Bindi, Luca; Chen, Ming; Xie, Xiande. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - ELETTRONICO. - 7:(2017), pp. 1-8.
Discovery of the Fe-analogue of akimotoite in the shocked Suizhou L6 chondrite
BINDI, LUCA;
2017
Abstract
We report the first natural occurrence of the Fe-analogue of akimotoite, ilmenite-structured MgSiO3, a missing phase among the predicted high-pressure polymorphs of Fe-pyroxene, with the composition (Fe2+ 0.48Mg0.37Ca0.04Na0.04Mn2+ 0.03Al0.03Cr3+ 0.01)Σ=1.00Si1.00O3. The new mineral was approved by the International Mineralogical Association (IMA 2016-085) and named hemleyite in honour of Russell J. Hemley. It was discovered in an unmelted portion of the heavily shocked L6 Suizhou chondrite closely associated to olivine, clinoenstatite and Fe-bearing pyroxene with a composition nearly identical to that of hemleyite. We also report the first single-crystal X-ray diffraction study of a Si-bearing, ilmenitestructured phase. The fact that hemleyite formed in a meteorite exposed to high pressures (<20 GPa) and temperatures (<2000 °C) during impact-induced shocks indicates that it could play a crucial role at the bottom of the Earth’s mantle transition zone and within the uppermost lower mantle.File | Dimensione | Formato | |
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