Diamonds and highly reduced minerals in ophiolitic mantle rocks and chromitites

摘要

Ophiolitic mantle rocks and chromitites are generally thought to have formed near the top of the upper mantle.However, our discovery of diamonds and highly reduced minerals in ophiolitic chromitites significantly challenges this model Some new progresses are summarized as below: 1.A very significant milestone is that the diamonds have now been shown to occur in situ within chromite grains from the Luobusa and Polar Ural chromitites.This discovery has ended all doubts about the diamonds being the result of contamination during sample processing.Previously such contamination could not be conclusively ruled out because all the diamonds had been obtained from mineral separates.