永利集团官方网站入口

Digging deep

作者:武炯    发布时间:2019-03-07 05:20:03    

ROCKS from 700 kilometres beneath the Earth’s surface have been found by Australian geochemists. The deepest-ever rocks come from volcanic pipes on Malaita Island in the Solomon Islands. Magma rising from the Earth’s lower mantle broke off chunks of mantle rock and carried them to the surface. These xenoliths contain mineral crystals such as diamonds that are formed at high pressure. Ken Collerson of the University of Queensland in Brisbane told the American Geophysical Union in San Francisco last month that some crystals were only formed at pressures of more than 22 gigapascals,

 

Copyright © 网站地图