Tibet found that the ultra-high pressure new minerals are mostly nano-scale

The International Journal of Mineralogy published in August announced the newly approved minerals of the International Minerals Society this year. The boron nitride minerals discovered by Chinese and foreign scientists were approved and named “Qingsong Mine”. In recent years, the State Key Laboratory of Continental Sedimentation and Dynamics of the Chinese Academy of Geological Sciences, led by researcher Yang Jingwei, has conducted extensive cooperation with international counterparts to obtain a series of studies on the ultrahigh pressure minerals of ophiolite mantle and chromite. progress.

They found diamonds in 10 ophiolites in five orogenic belts around the world, and found diamond inclusions in coesite and antimony ore in chromite ore, and nanoscale super in coesite. Special mineral inclusions such as titanium nitride and boron nitride that are caused by high pressure. The composition analysis showed that the boron content of Qingsong Mine was 48.54%, the nitrogen content was 51.46%; the particle size was very small, the largest particle was only 1 micron, most of the particle size was nanometer; the formation temperature was 1300 ° C, the pressure was 10-15 GPa, which formed The depth is greater than 300 kilometers.

The discovery of the Qingsong Mine and a series of other ultra-high pressure minerals, as well as the discovery of deep minerals such as diamonds in different orogenic belts around the world, indicate that the mantle beneath the oceanic expansion ridge carries a large number of deeply formed mantle minerals and their accompanying chromite upwelling. To the shallow part. This finding provides a new interpretation of the current prevalence of chromite ore in the international community and will affect the understanding of the genesis of ophiolite and oceanic crust.

Louis Leo, a professor at Stanford University in the United States, pointed out: "The discovery of ultra-high pressure minerals in ophiolite chromite ore breaks the notion that traditional ophiolite chromite ore is formed in high temperature, low pressure mid-ocean ridges or post-arc expansion environments. The discovery of similar findings in other ophiolites has evoked interest in finding ultra-high pressure inclusions in the global ophiolite chromite ore." International Super High Voltage Committee Chairman Lalisa Daw Pozny Kaya also pointed out "The new discovery opens up a new field of research on the debris of the continental material and the Fanghui peridotite mantle peridotite mixture."