Science. 1995 Jun 23;268(5218):1743-5. doi: 10.1126/science.268.5218.1743.
To study the crystallography of Earth's lower mantle, techniques for measuring synchrotron x-ray diffraction from a laser-heated diamond anvil cell have been developed. Experiments on samples of (Mg, Fe)SiO(3) show that silicate perovskite maintains its orthorhombic symmetry at 38 gigapascals and 1850 kelvin. Measurements at 65 and 70 gigapascals provide evidence for a temperature-induced orthorhombic-to-cubic phase transition and dissociation to an assemblage of perovskite and mixed oxides. If these phase transitions occur in Earth, they will require a significant change in mineralogical models of the lower mantle.
为了研究地球下地幔的晶体结构，已经开发出了用于测量激光加热金刚石压腔中同步加速器 X 射线衍射的技术。对（Mg，Fe）SiO3 样品的实验表明，硅酸盐钙钛矿在 380 吉帕斯卡和 1850 开尔文下保持正交对称。在 65 和 70 吉帕斯卡下的测量结果为温度诱导的正交-立方相转变以及向钙钛矿和混合氧化物组合体的解离提供了证据。如果这些相变发生在地球上，它们将需要对下地幔的矿物学模型进行重大修改。
