Physical properties of deep Earth minerals and the effect of water

我们已经阐明了深部地幔矿物的物理性质和水的影响。除了淬火实验外，还进行了现场X射线测量。根据我们以往的研究，橄榄石、瓦兹利石和环木石的高压晶型的晶体结构中可以含有2-3wt%的H_2O，但H_2O在这些矿物中的分配尚不清楚。在本研究中，我们阐明了H2O的分配以合成这些共存相，发现地幔过渡带应该是地球内部的一个强大的储水层。此外，通过对含水水滑石和水合环杉石的热膨胀和弹性性质的测量，确定了地幔中的H2O含量。结合地震观测结果，估算了地幔中的H2O含量。与地震学家进行了更广泛的研究。我们还试图通过原位X射线观察，观察相对轻金属胶囊包裹的高压水合相的脱水和物理性质。我们利用AgPd胶囊成功地获得了高水相B相的X射线能谱，并进一步改进了由单晶金刚石套和金属帽制成的胶囊，用于原位X射线实验。通过现场X射线实验，实现了高压下X射线能谱的有效获取。该技术已用于确定含水熔体的结构和脱水的时间分辨实验。

We have clarified the physical properties of deep Earth mantle minerals and the effect of water. Experiments were conducted by in situ X-ray measurements in addition to quench experiments.From our previous studies, it has been clarified that high pressure polymorphs of olivine, wadsleyite and ringwoodite, can contain 2-3 wt% of H_2O in their crystal structures, but the partitioning of H_2O among these minerals has not been clarified yet. In the present study, we have clarified the partitioning of H_2O to synthesize these coexisting phases, and found that mantle transition zone should be a strong water reservoir in the Earth's interior.In addition, the measurements of thermal expansion and elastic properties of hydrous wadsleyite and hydrous ringwoodite were conducted to clarify the H_2O content in the mantle. Combined these results with seismic observation, we estimated the H_2O content in the mantle. Further extensive studies have been conducted with seismologist.We also tried to observe dehydration and physical properties of high pressure hydrous phase with capsulation using relatively light metal capsule by in situ X-ray observation. We succeeded to get X-ray spectra of superhydrous phase B using AgPd capsule, and further improved capsule, which were made by a single crystal diamond sleeve and metal caps, were designed for in situ X-ray experiment. The capsule is quite successful, and the effective acquisition of X-ray spectra under high pressure has been achieved by in situ X-ray experiment. This technique has been adopted to determine hydrous melt structure and time-resolved experiment of dehydration.