Kinetics of the post-gamet transformation and dynamics of the subducting oceanic plates

配子后转变动力学和俯冲海洋板块动力学

• 批准号: 15340181
• 负责人: KUBO Tomoaki
• 金额: $ 10.82万
• 依托单位: KYUSHU UNIVERSITY (2004)Tohoku University (2003)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15340181/
• 关键词: hiah-pressure experiments; in-situ X-ray diffraction; sintered diamond multi-anvil; TEM; high-pressure transformations of mantle minerals; transformation kinetics; subducting oceanic plates; stagnant slabs; 相転移メカニズム; マントルダイナミクス

We have developed techniques on high-pressure generations using sintered diamond multi-anvil systems combined with synchrotron radiation, which enables to obtain time-resolved X-ray diffraction data every 10-30 seconds up to 35 GPa and 2000K. We also tested new sintered diamond anvils manufactured by Ringwood Superabrasives for the X-ray window of multi-anvil apparatus.Based on these techniques, we have quantitatively studied on kinetics of post garnet transformations in natural garnet, high-pressure transformations in pyroxenes (enstatite and diopside), and effects of water on the olivine-spinel transformation kinetics. Transformation microstructures and water contents of samples recovered were examined using TEM and FTIR. In addition to these studies, we have also examined about formation of metastable cubic perovskite, dehydration reaction of high-pressure hydrous minerals, and mechanisms and kinetics of high-pressure transformations in shocked meteorites, those have important implications for subduction processes. Cation diffusion kinetics in wadsleyite have been experimentally examined and rheology of subducting plates and mantle transition zone was discussed.We have extrapolated quantitative kinetic data obtained to subduction zone conditions and construct metastable mineralogy in subducting plates. We have calculated the density of subducting slabs taking transformation kinetics into accounts, which suggests that the subducting slabs are buoyant at the top of the lower mantle due to the presence of metastable low-pressure phases. Grain-size reductions caused by non-equilibrium transformations can reduce strength of subducting plates. These are important for the formation of stagnant slabs at the top of the lower mantle.

我们开发了使用烧结金刚石多砧系统与同步加速器辐射相结合的高压生成技术，能够每 10-30 秒获取高达 35 GPa 和 2000K 的时间分辨 X 射线衍射数据。我们还测试了Ringwood Superabrasives公司生产的新型烧结金刚石砧，用于多砧装置的X射线窗口。基于这些技术，我们定量研究了天然石榴石中石榴石后转变的动力学，辉石（顽辉石）中的高压转变的动力学。和透辉石），以及水对橄榄石-尖晶石转变动力学的影响。使用 TEM 和 FTIR 检查回收样品的相变微观结构和水含量。除了这些研究之外，我们还研究了亚稳立方钙钛矿的形成、高压含水矿物的脱水反应以及冲击陨石中高压转变的机制和动力学，这些对俯冲过程具有重要意义。对瓦兹利石中的阳离子扩散动力学进行了实验研究，并讨论了俯冲板块和地幔过渡带的流变学。我们将获得的定量动力学数据外推到俯冲带条件，并构建了俯冲板块的亚稳矿物学。我们计算了俯冲板片的密度，考虑了转变动力学，这表明由于亚稳态低压相的存在，俯冲板片在下地幔顶部是有浮力的。非平衡转变引起的晶粒尺寸减小会降低俯冲板块的强度。这些对于下地幔顶部静止板块的形成很重要。

项目成果

Water solubility in Mg-perovskite and water storage capacity in the lower mantle

镁钙钛矿的水溶性和下地幔的储水能力

• 发表时间: 2003
• 期刊: Earth Planet.Sci.Lett. vol.211
• 作者: K.Litasov;E.Ohtani;F.Langenhordt;H.Yurimoto;T.Kubo;T.Kondo
• 通讯作者: T.Kondo

T.Katsura, K.Funakoshi, A.Kubo, N.Nishiyama, Y.Tange, Y.Sueda, T.Kubo他: "A Kawai-type high-pressure and high-temperature apparatus for in situ X-ray observation,'SPEED-Mk.II'"Phys.Earth Planet. Inte. (発表予定). (2004)

T.Katsura、K.Funakoshi、A.Kubo、N.Nishiyama、Y.Tange、Y.Sueda、T.Kubo 等人：“一种用于原位 X 射线的 Kawai 型高压高温装置观测，“SPEED-Mk.II”“Phys.Earth Planet.Inte.（待公布）。（2004）

In situ X-ray observation of decomposition of hydrous aluminum silicate AlSiO_3OH and aluminum oxide hydroxide δ-AlOOH at high pressure and temperature

高压高温下水合硅酸铝AlSiO_3OH和氢氧化铝δ-AlOOH分解的原位X射线观察

• 发表时间: 2004
• 期刊: Journal of physics and Chemistry of solid 65
• 作者: A.Sano;E.Ohtani;T Kubo;K.Funakoshi
• 通讯作者: K.Funakoshi

Silicon self-diffusion in wadsleyite : Implications for rheology of the mantle transition zone and the subducting plates

瓦兹利石中的硅自扩散：对地幔过渡带和俯冲板块流变学的影响

• 发表时间: 2004
• 期刊: Geophysical Research Letters 31
• 作者: A.Shimojuku;T.Kubo;E.Ohtani;H.Yurimoto
• 通讯作者: H.Yurimoto

Water solubility in Mg-perovskite and and water storage capacity in the lower mantle

镁钙钛矿的水溶性和下地幔的储水能力

• 发表时间: 2003
• 期刊: Earth Planet.Sci.Lett. 211
• 作者: K.Litasov;E.Ohtani;F.Langenhordt;H.Yurimoto;T.Kubo;T.Kondo
• 通讯作者: T.Kondo