In investigating Quaternary permafrost rocks in various regions of Yakutia, we come across neogenic alumina in the form of friable white and yellowish spheres about 0.1 mm in diameter. The spherical alumina concretions ...
Corundum is formed primarily by igneous activity, and by contact and regional metamorphism. The finding of supergene corundum in syngenetically frozen sedimentary rocks of Yakutia reflects the specific characteristics of ...