Characterization of high pressure and natural samples by Raman spectroscopy

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 12440150
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Petrology/Mineralogy/Science of ore deposit
• Research Institution: OKAYAMA UNIVERSITY
• Principal Investigator: WALTER Michael Institute for Study of Earth's Interior, Okayama University, Professor, 固体地球研究センター, 教授 (20284094)
• Co-Investigator(Kenkyū-buntansha): KATSURA Tomoo Institute for Study of Earth's Interior, Okayama University, Associate Professor, 固体地球研究センター, 助教授 (40260666) ; KANZAKI Masami Institute for Study of Earth's Interior, Okayama University, Associate Professor, 固体地球研究センター, 助教授 (90234153) ; ITO Eiji Institute for Study of Earth's Interior, Okayama University, Professor, 固体地球研究センター, 教授 (00033259) ; NAKAMURA Eizo Institute for Study of Earth's Interior, Okayama University, Professor, 固体地球研究センター, 教授 (80201672)
• Project Period (FY): 2000 – 2001
• Keywords: Raman spectroscopy / diamond anvil cell / mineral inclusions / in situ mineral analysis

Research Abstract

In the proposal period we purchased and installed the equipment needed for a micro-Raman spectroscopy system, as well as the Type II diamonds needed for in situ spectroscopy in the diamond anvil cell. The installed Raman microprobe system was designed specifically to meet the needs of our high-pressure materials research group, and for the investigation of Earth and solar system materials. The installed system has achieved a very high performance, with a spectral resolution of about 0.5 nm and high optical throughput. This system is now used routinely in our lab for identification of phases synthesized in high-pressure experiments and to investigate natural minerals. In the proposal period we have used micro-Raman to identify many synthetic and natural silicate and oxide phases and have built a file to use as reference standards. We have also used the micron-Raman system to positively identify the existence of a high-pressure polymorph of SiO_2, coesite, in eclogite xenoliths from the Colorado plateau, the first reported for eclogites of this region. We have used the system to investigate the effect on melt speciation and polymerization of adding sulfur to sodium silicate melts, and are continuing investigations into melt speciation in depolymerized silicate systems. The micro-Raman system is also used routinely in our lab to measure pressure in situ in the diamond anvil cell using Ruby fluorescence. We are continuing to be engaged in projects in which Raman microscopy plays an important role.