Studies on material properties of the subducted slab and lower mantle

我们设计并安装了用于现场x射线观测的大体积高P-T仪器SPEED-Mk。第三代同步辐射设备SPring-8的白色x射线束线BL04B1中的II。通过使用烧结金刚石砧，我们将多砧装置产生的压力范围从40 GPa扩大到63 GPa。SPEED-Mk。II配有振荡系统，使我们能够获得高质量的晶粒生长衍射图。我们通过测定NaCl中B1-B2相变的相界证明了该体系的有效性。我们在地球科学方面也得到了下列结果。1)通过核磁共振波谱法发现，由于Al_2O_3的取代，镁钙钛矿中存在氧缺陷。2)用共振技术测定了MgSiO_3钙钛矿、Mg_2SiO_4环伍德矿和Mg_2SiO_4瓦德利矿剪切模量和体积模量的压力依赖性。3)测定了压力高达33gpa时橄榄岩的熔融关系。4)我们研究了铁的相关系，发现没有最近一些研究报道的beba相。5)确定了CaSiO_3钙钛矿在40gpa下的状态方程。6)确定了MgAl_2O_4铁氧体钙的稳定性关系。7)研究了NaAlSiO_4中的相关系，确定了铁酸钙相的稳定场。8)我们测量了（Mg, Fe）_2SiO_4钙钛矿和钛铁矿高达40gpa的电导率。

We have designed and installed the large-volume high P-T apparatus for in situ X-ray observation, SPEED-Mk.II in the white-X-ray beam line BL04B1 at the third generation synchrotron radiation facility, SPring-8. By using sintered diamond anvils, we have extended the pressure range generated by multi-anvil apparatus from 40 to 63 GPa. SPEED-Mk.II is equipped with the oscillation system, which enables us to obtain high-quality diffraction pattern against grain growth. We have demonstrated the usefulness of this system by determining the phase boundary of B1-B2 transition in NaCl.We have also obtained the following results in earth sciences. 1)We have shown presence of oxygen defect in Mg-perovskite due to the substitution of Al_2O_3 by means of NMR spectroscopy. 2)We have determined pressure dependence of shear and bulk moduli of MgSiO_3 perovskite, Mg_2SiO_4 ringwoodite and Mg_2SiO_4 wadsleyite by resonance technique. 3)We have determined the melting relation in peridotite at pressures up to 33 GPa. 4)We have studied the phase relation of iron, showing absence of beba-phase that is recently reported by several studies. 5)We have determined the equation of state of CaSiO_3 perovskite up to 40 GPa. 6)We have determined the stability relations of MgAl_2O_4 calcium ferrite. 7)We have studied the phase relations in NaAlSiO_4, determining the stability field of the calcium ferrite phase. 8)We have measured electrical conductivities of (Mg, Fe)_2SiO_4 perovskite and ilmenite up to 40 GPa.