|Budget Amount *help
¥217,000,000 (Direct Cost: ¥217,000,000)
Fiscal Year 1999: ¥12,000,000 (Direct Cost: ¥12,000,000)
Fiscal Year 1998: ¥12,000,000 (Direct Cost: ¥12,000,000)
Fiscal Year 1997: ¥12,000,000 (Direct Cost: ¥12,000,000)
Fiscal Year 1996: ¥71,000,000 (Direct Cost: ¥71,000,000)
Fiscal Year 1995: ¥110,000,000 (Direct Cost: ¥110,000,000)
The purpose of the present project was to study the structure and density of silicates and oxides under lower mantle condition and to test various dynamic models of the Earth based on these new information in mineral physics. For this purpose, high pressure and high temperature in situ X-ray diffraction system was constructed by combining laser heated diamond anvil cell and synchrotron radiation. Behavior of various silicates and oxides were studied up to 140 GPa and some new unquenchable high pressure minerals were discovered. Particularly studied were the behavior of silicates containing large amount of aluminum, which are expected to be an important constituent of subducting slab. Detailed phase relations and the structure of new high pressure polymorphs are clarified through the present study. Precise phase boundary and equations of state of natural garnets were also studied. All these data provide important information to calculate density contrast of various phases in the lower mantle. Since the actual Earth is a multi-component system with complex composition, it is still not easy to make strong argument. However, present project made it possible to perform in situ X-ray diffraction study under the condition corresponding to the Earth's lower mantle, and various new knowledges on the behavior of minerals under these conditions were obtained through the present study.