Crystal structure refinement of mantle minerals under high pressure and temperature using Rietveld method

Rietveld法高温高压下地幔矿物晶体结构细化

基本信息

批准号：
13440162
负责人：
NAGAI Takaya
金额：
$ 9.22万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13440162/
关键词：
laser annealing high pressure high temperature mantle minerals structure refinement Rietveld method diamond anvil cell

项目摘要

In-situ X-ray diffraction measurements under pressure were performed on several minerals and obtained powder diffraction patterns were analyzed by means of Rietveld structure refinement method. High pressure is generated by a diamond anvil cell (DAC) and X-ray diffraction experiments were mainly performed in synchrotron radiation facilities, such as PF and SPring8.Shortening of hydrogen bonded oxygen-oxygen distances controls compression of some hydrous minerals, such as KHCO_3 and NaHCO_3. A phase transition occurs on KHCO_3 at about 2.8 Gpa. It is interesting thai hydrogen bonded O-O distance in NaHCO_3 reaches to 2.4 A^^○ at 9 Gpa and this suggests a possibility of hydrogen bond symmetrization. Shortening of hydrogen bonded O-O distance also controls compression behavior of goethite and its shortening behavior is quite similar to that of ice VII.Laser annealing is quile useful for relaxing strain in materials caused by nonhydrostatic pressure Laser annealing was applied to compression experiments of NiTiO_3-ilmenite in PF. Obtained diffraction patterns after annealing treatment were greatly improved and Rietveld analysis could be done successfully up to 20 Gpa.Laser heating is a powerful method for creating lower mantle conditions on the earth. We performed insitu X-ray diffraction experiments under high pressure and temperature conditions at SPnng8 to clarify a possibility of a reaction between maguesite and iron. No evidence of the reaction was observed at 2000℃ and 1000℃ at 40 Gpa Diffraction patterns of CaSiO_3 perovskite could be observed at 20 Gpa and 1500-1600 K. Technical improvements are still needed but quite good quality diffraction patterns were recorded.EOS of CaO was determined by X-ray diffraction measurements using a hydraulically operated DAC and discusses a possibility of dissociation reaction of CaSiO_3 perovskile at the lowest part of the lower mantle.

在压力下进行了原位X射线衍射测量，在几个矿物上进行了压力，并通过Rietveld结构改进方法分析了粉末衍射模式。高压是由钻石砧（DAC）产生的，X射线衍射实验主要是在同步加速器辐射设施中进行的，例如PF和Spring8。大约2.8 GPA上的KHCO_3上发生相变。有趣的泰氢在NAHCO_3中键合的O-O距离达到2.4 a ^^○在9 GPA时，这表明氢键键合的O-O距离还可以控制gothite的压缩行为，其缩短行为非常相似，其缩短行为与ICE VII的材料对材料的质量施加了质量的质量，使其与ICE VII相似。 pf中的nitio_3-ilmenite。退火处理后获得的衍射模式得到了极大的改善，并且可以成功进行20 GPA。激光加热是一种在地球上产生较低地幔条件的有力方法。我们在SPNNG8的高压和温度条件下进行了无效的X射线衍射实验，以阐明Maguesite和铁之间反应的可能性。 No evidence of the reaction was observed at 2000℃ and 1000℃ at 40 Gpa Diffraction patterns of CaSiO_3 perovskite could be observed at 20 Gpa and 1500-1600 K. Technical improvements are still needed but quite good quality diffraction patterns were recorded.EOS of CaO was determined by X-ray diffraction Measurements using a hydroluably operated DAC and discusses a possibility of dissociation reaction of CaSiO_3下地幔的最低部分的perovskile。