In situ X-ray observations of phase transitions in MgAl 2 O 4 spinel to 40 GPa using multianvil apparatus with sintered diamond anvils

Irifune, Tetsuo; Naka, Hisanobu; Sanehira, T.; Inoue, Toru; Funakoshi, Kengo

doi:10.1007/s00269-002-0275-1

Cited by 70 publications

(34 citation statements)

References 26 publications

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“…There is no evidence for an intermediate decomposition process, such as the postspinel transitions of MgAl 2 O 4 (5,7,12). The results indicate that the solid-state phase transformation is, in general, a dominating mechanism for the formation of highpressure minerals in naturally shocked meteorites (16).…”

Section: Discussionmentioning

confidence: 81%

“…Previous experiments showed that MgAl 2 O 4 might also take the CF or CT structures at specific P-T conditions (5,7,9,12). This finding has implications for the widespread cation substitution of Al for Cr and between Mg and Fe in this structure type.…”

Section: Discussionmentioning

confidence: 84%

“…1). Although ferromagnesian silicate spinels were later found to break down to simple oxides (3) or stishovite plus perovskite (4), several postspinel oxides convert to a single phase with the CF or CT structure (1,2,(5)(6)(7)(8)(9)(10)(11)(12). Neither dense postspinel polymorphs nor silicate perovskites, however, have been discovered in nature and confirmed as new minerals.…”

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confidence: 99%

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Natural occurrence and synthesis of two new postspinel polymorphs of chromite

Chen

Shu

Mao

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

111

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A high-pressure polymorph of chromite, the first natural sample with the calcium ferrite structure, has been discovered in the shock veins of the Suizhou meteorite. Synchrotron x-ray diffraction analyses reveal an orthorhombic CaFe 2O4-type (CF) structure. The unit-cell parameters are a ‫؍‬ 8.954(7) Å, b ‫؍‬ 2.986(2) Å, c ‫؍‬ 9.891(7) Å, V ‫؍‬ 264.5(4) Å 3 (Z ‫؍‬ 4) with space group Pnma. The new phase has a density of 5.62 g͞cm 3 , which is 9.4% denser than chromitespinel. We performed laser-heated diamond anvil cell experiments to establish that chromite-spinel transforms to CF at 12.5 GPa and then to the recently discovered CaTi 2O4-type (CT) structure above 20 GPa. With the ubiquitous presence of chromite, the CF and CT phases may be among the important index minerals for natural transition sequence and pressure and temperature conditions in mantle rocks, shock-metamorphosed terrestrial rocks, and meteorites. F orty years ago, in search of denser polymorphs of the then newly discovered silicate spinel (ringwoodite) and modified spinel (wadsleyite) that are stable at the pressure and temperature (P-T) conditions of the Earth's transition zone, Ringwood (1, 2) proposed orthorhombic CaFe 2 O 4 -type (CF) and CaTi 2 O 4 -type (CT) structures as the top candidates for ''postspinel'' transitions in the Earth's mantle (Fig. 1). Although ferromagnesian silicate spinels were later found to break down to simple oxides (3) or stishovite plus perovskite (4), several postspinel oxides convert to a single phase with the CF or CT structure (1, 2, 5-12). Neither dense postspinel polymorphs nor silicate perovskites, however, have been discovered in nature and confirmed as new minerals. Many natural high-pressure minerals presumably predominating in the Earth's mantle have been found mainly in the shock-metamorphosed meteorites, which include ringwoodite, wadsleyite, silicate ilmenite, magnesiowüs-tite, (Na,K)AlSi 3 O 8 -hollandite, and poststishovite polymorphs (13-19). Special P-T conditions developed in the impacted meteorites, for instance, a long duration of high-pressure and -temperature up to several seconds and quenching under pressure, play an important role in the formation and preservation of high-pressure phases (16). It makes the naturally shockmetamorphosed meteorites a window for discovery of new high-pressure minerals and for investigation of the constituents in the deep Earth. Preliminary examination of the Suizhou meteorite has recently revealed a shock-metamorphosed CT polymorph of chromite composition (20). In this article, we report the identification of a previously uncharacterized CF polymorph of chromite in the same meteorite. High P-T experiments demonstrate that both CF and CT are indeed quenchable polymorphs of chromite formed above 12.5 and 20 GPa, respectively.The Suizhou meteorite is a moderately shock-metamorphosed L6-chondrite, and a shock stage S5 was estimated for the meteorite according to the classification of shock metamorphism (21). The meteorite contains shock-produced melt veins ranging...

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Section: Discussionmentioning

confidence: 81%

Section: Discussionmentioning

confidence: 84%

mentioning

confidence: 99%

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Natural occurrence and synthesis of two new postspinel polymorphs of chromite

Chen

Shu

Mao

et al. 2003

Proc. Natl. Acad. Sci. U.S.A.

111

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“…Earlier studies have repeatedly examined the compressibility of these two phases synthesized in both natural and simplified systems (Yutani et al 1997;Funamori et al 1998Funamori et al , 2000Dubrovinsky et al 2002;Irifune et al 2002;Ono et al 2002a, b;Vanpeteghem et al 2003;Guignot and Andrault 2004;Shinmei et al 2005), but none of them were made for a given chemical composition for both the NAL and CF phases. It precludes the direct comparison of the NAL phase and its high-pressure phase, the CF phase, in compression behavior, elastic property, and density at high pressure.…”

Section: Introductionmentioning

confidence: 99%

Compression of Na0.4Mg0.6Al1.6Si0.4O4 NAL and Ca-ferrite-type phases

et al. 2012

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Compression behaviors of two Al-rich phases in the lower mantle, hexagonal new aluminum-rich (NAL) phase and its high-pressure polymorph Ca-ferrite-type (CF) phase, were examined for identical Na 0.4 Mg 0.6 Al 1.6 Si 0.4 O 4 (40 % NaAlSiO 4 -60 % MgAl 2 O 4 ) composition. The volumes of the NAL and CF phases were obtained at room temperature up to 31 and 134 GPa, respectively, by a combination of laser-annealed diamond-anvil cell techniques and synchrotron X-ray diffraction measurements. Fitting of the third-order Birch-Murnaghan equation of state to such pressure-volume data yields bulk modulus K 0 = 199(6) GPa at 1 bar and its pressure derivative K 0 0 = 5.0(6) for the NAL phase and K 0 = 169(5) GPa and K 0 0 = 6.3(3) for the CF phase. These results indicate that the bulk modulus increases from 397 to 407 GPa across

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“…The size of the SD anvil has been extended in the 1990s from a 5e10-mm to 14-mm edge length and this highpressure technique has been developed and applied to study mineral properties and phase transitions in the MAA by using the traditional quenched method (Ito et al, 1998), or by combining with the synchrotron X-ray diffraction technique (Kato et al, 1992;Kondo et al, 1993;Funamori et al, 1996aFunamori et al, , 1996b. High-pressure generation using SD anvils has been extended significantly, especially in the last decade, including the Earth Science research field with many studies carried out (Ito, 2000;Ono et al, 2000Ono et al, , 2001Irifune, 2002;Irifune et al, 2002;Ito and Kubo, 2002;Kubo et al, 2003;Yamazaki and Irifune, 2003;Ito et al, 2004;Ohtani, 2004;Sueda et al, 2004;Ito et al, 2005;Ito, 2006;Yamazaki et al, 2006;Ito, 2007;Stewart et al, 2007;Kubo et al, 2008;Shinmei et al, 2008;Tange et al, 2008;Ito et al, 2009Ito et al, , 2010Katsura et al, 2009;Sueda et al, 2009;Yamazaki et al, 2011). In this paper we review the advances of high-pressure generation in the MAA by adopting the SD cubic anvil and we also discuss the problems and perspectives of this technique.…”

Section: Introductionmentioning

confidence: 99%

Recent advances of high-pressure generation in a multianvil apparatus using sintered diamond anvils

Zhai

Ito

2011

Geoscience Frontiers

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The tried and tested multianvil apparatus has been widely used for high-pressure and hightemperature experimental studies in Earth science. As a result, many important results have been obtained for a better understanding of the components, structure and evolution of the Earth. Due to the strength limitation of materials, the attainable multianvil pressure is generally limited to about 30 GPa (corresponding to about 900 km of the depth in the Earth) when tungsten carbide cubes are adopted as second-stage anvils. Compared with tungsten carbide, the sintered diamond is a much harder material. The sintered diamond cubes were introduced as second-stage anvils in a 6e8 type multianvil apparatus in the 1980s, which largely enhanced the capacity of pressure generation in a large volume press. With the development of material synthesis and processing techniques, a large sintered diamond cube (14 mm) is now available. Recently, maximum attainable pressures reaching higher than 90 GPa (corresponding to about 2700 km of the depth in the Earth) have been generated at room temperature by adopting 14-mm sintered diamond anvils. Using this technique, a few researches have been carried out by the quenched method or combined with synchrotron radiation in situ observation. In this paper we review the properties of sintered diamond and the evolution of pressure generation using sintered diamond anvils. As-yet unsolved problems and perspectives for uses in Earth Science are also discussed. ª 2011, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

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In situ X-ray observations of phase transitions in MgAl 2 O 4 spinel to 40 GPa using multianvil apparatus with sintered diamond anvils

Cited by 70 publications

References 26 publications

Natural occurrence and synthesis of two new postspinel polymorphs of chromite

Natural occurrence and synthesis of two new postspinel polymorphs of chromite

Compression of Na0.4Mg0.6Al1.6Si0.4O4 NAL and Ca-ferrite-type phases

Recent advances of high-pressure generation in a multianvil apparatus using sintered diamond anvils

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