CH_4-rich fluid inclusions in the Yushigou mantle peridotite and their implications, North Qilian Mountains, China

摘要

Studies were carried out on the early phase of fluid inclusions which occur in residual olivines in harzburgite from the Yushigou ophiolitic mantle peridotite, the North Qilian Moun- tains. Components of these inclusions, analyzed by micro laser Raman spectroscopy, are dominantly CH_4(70/100-95/100)with minor H_2, N_2, H_2S, CO_2, C_2H_4, C_2H_6, and C_3H_6, but there are no H_2O, CO and SO_2. The highly CH_4-rich fluid was probably derived from an ancient deep mantle. This discovery plays an important role in all-round understanding of the fluid property of the upper mantle, especially the ancient oceanic upper mantle.