HIGH PRESSURE MODIFICATION OF MG2SIO4 - CRYSTAL STRUCTURE AND CRYSTALLOCHEMICAL AND GEOPHYSICAL IMPLICATIONS

被引：13

作者：

MOORE, PB

SMITH, JV

机构：

[1] Department of the Geophysical Sciences, University of Chicago, Chicago

来源：

NATURE | 1969年 / 221卷 / 5181期

关键词：

D O I：

10.1038/221653a0

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

The polymorphic transformation of (Mg,Fe)2SiO4 from the olivine structure type (denoted I) to the spinel type (denoted III) plays a key part in the Earth's mantle at depths between 350 and 1,000 km. The situation is complicated, for Ringwood and Major1 synthesized yet a third phase for compositions more magnesian than Mg0.85Fe0.15, which overlap the range Mg0.8 to Mg0.9 thought to represent mantle material. This phase (denoted II) possesses an X-ray powder diffraction pattern the strong lines of which are similar to those of spinel, but which contains many extra weak lines. It is optically birefringent. Ringwood and Major suggested that the phase may be a distorted spinel, and that the distortion occurred during quenching of an original true spinel. © 1969 Nature Publishing Group.

引用

页码：653 / &