Varieties of Impactites and Impact Diamonds of the Kara Meteorite Crater (Pay-Khoy, Russia)

Tatyana Shumilova,Nadezhda Maximenko,Vasily Ulyashev,Natalya Kovalchuk,Alexandr Zubov,Viktoria Kis

doi:10.1088/1755-1315/362/1/012043

Abstract

Impact diamonds are technical material with valuable mechanical properties. Despite of a quite long story from their discovery and huge diamond storages at the Popigai astrobleme (Siberia, Russia) they were not involved into industrial production, first of all because of remoteness of objects, complexity of extraction and economically more favourable synthesis of technical diamonds in the seventies of the past century. However, due to the high hardness of impact diamonds and also to the high demand of new carbon materials, including nanomaterials, the interest towards this type of natural diamonds is significantly increased in the recent years. Although the mentioned Popigai astrobleme is situated in a remote part of Russia it has been studied in more details. At the same time, the less known Kara giant meteorite crater (Pay-Khoy, Russia) is situated essentially closer to the industrial infrastructure of the European part of Russia. This astrobleme, similarly to Popigai, is enriched in impact diamonds as well. But, till recent years it was not deeply studied using modern analytical methods. During our studies in 2015 and 2017 at the territory of the Kara meteorite crater we have distinguished and described 5 varieties of impactites – bulk melt impactites which form cover-like and thick dike bodies; melt ultrahigh-pressure vein bodies and at least 3 types of suevites formed after specific sedimentary target rocks. These varieties have typomorphic features regarding the crystallinity and mineral composition. It was found that all of them have high concentration of microdiamonds formed by high-pressure high temperature pyrolysis mechanism from precursor materials like coal and organic relicts. Using a set of modern mineralogical methods we have found two principal types of diamond morphologies within the Kara impactites – sugar-like after coal diamonds and diamond paramorphs after organic relicts. The Kara diamonds have several accompanying carbon substances including newly formed graphite, glass-like carbon and probably carbyne. The studied diamondiferous Kara impactites provide an essentially novel knowledge of impact processes in sedimentary targets.

Highlights

Impactites are intensively studied objects around the world, as meteorite cratering is one of the crucial geological processes of the formation of Earth crust and mineral deposits [1,2,3,4,5,6]
Despite of a quite long story from their discovery and huge diamond storages at the Popigai astrobleme (Siberia, Russia) they were not involved into industrial production, first of all because of remoteness of objects, complexity of extraction and economically more favourable synthesis of technical diamonds in the seventies of the past century
The mentioned Popigai astrobleme is situated in a remote part of Russia it has been studied in more details

Summary

Introduction

Impactites are intensively studied objects around the world, as meteorite cratering is one of the crucial geological processes of the formation of Earth crust and mineral deposits [1,2,3,4,5,6]. There are about 190 proven meteoritic craters on the Earth, among them the diamondiferous astroblemes attract especial attention as significant reservoirs of high quality technical diamonds [6]. At the territory of the Popigai impact crater 2 deposits with estimated huge diamond resources are known – Udarnoe and Skalnoye. Despite of their quite old story dating back to pioneer studies of the diamond objects in the in the seventies of the past century , they were not involved into industrial production mainly due to the remoteness of these objects, the complexity of their extraction and on the other hand, the economically more favorable synthesis of technical diamonds. During our studies of impactites from the Kara astrobleme we have revealed new types of impactites and impact diamonds, including a new variety of impact diamond – diamond fossils in very high concentrations [13, 14]

Methods

Results

Conclusion