Graphite in rocks of the Popigai impact crater: residual or retrograde?

Authors : Valentin AFANASIEV, Sergey GROMILOV, Valeri SONIN, Egor ZHIMULEV, Aleksei CHEPUROV

Pages : 470-477

View : 25 | Download : 9

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The concentration of diamond-bearing tagamite from the Popigai impact crater produces large amounts of graphite in addition to impact diamonds insert ignore into journalissuearticles values(1:100, respectively);. The question arises of whether this is residual graphite not converted to diamond at the time of the Popigai impact or is a retrograde form resulting from back-conversion of impact diamond to graphite in a high-temperature tagamite melt. Experiments show that graphite from tagamite is a residual phase. Coexistence of lonsdaleite, cubic diamond, and single-crystal graphite within a limited volume may be due to different orientations of the graphite base plane relative to the impact stress direction. Thus, the diamond-bearing rocks may contain significant amounts of residual graphite, which is consistent with published evidence.
Keywords : Impact crater, impact diamond, graphite, bulk graphitization, surface graphitization