矿物中氦的扩散过程及控制因素研究进展

Research progress on diffusion process and controlling factors of helium in minerals

研究氦在矿物中的初次运移过程是认识氦气成藏机制的基础。研究对氦的产生、扩散和释放过程及主要控制因素进行了系统综述。放射性元素U和Th发生α衰变后,产生的氦在晶格中可发生间隙迁移、与缺陷位复合,并通过自捕陷、迁移合并或热融合方式形成氦泡并长大,氦泡贯通后促进氦释放。氦也可通过α衰变形成的裂变径迹释放。氦源岩组成与晶体结构不同时,矿物对氦的封存能力存在显著差异;高温有利于氦的扩散与氦泡的长大,促进氦的释放;压裂及矿物转化过程也可引起氦的迅速释放。阐明氦初次运移的微观过程与主控因素,可为系统认识氦气的来源、运移聚集等成藏过程,以及氦气成藏理论的建立提供重要的理论基础。

The knowledge of the primary migration of helium is key for understanding the accumulation process of helium.In this review,the diffusion and release of helium in minerals and the controlling factors are systematically reviewed.Helium generated by the α decay of radioactive U and Th would undergo interstitial migration,combines with the vacancies,and accumulates to helium bubbles,which promotes the release of helium.Helium can also be released through fission tracks induced byαdecays.The difference in the composition and crystal structure of the minerals leads to different ability for storing helium.High temperature facilitates the diffusion of helium and the growth of helium bubbles,benefiting helium release.Fracturing and the transformation of minerals can also cause the rapid release of helium.Elucidating the processes of the primary migration of helium and the controlling factors should be of significant importance for understanding the source,migration and accumulation of helium reservoir.