Nanoporous nanocrystalline impact diamonds

Mineralogy and Petrology - Complementary nano- and atomic-scale data from SEM, FIB, HRTEM, and EELS observations of after-coal impact diamonds from the giant Kara astrobleme are described,...     

First Data on Molybdenite and Its Primary Sources in Pay-Khoy (Nenets Autonomous District): Mineralogy,Geochemistry, and Raman Spectroscopy

Doklady Earth Sciences - The first data on five primary molybdenite sources within the gabbro-dolerite complex of Pay-Khoy (Pay-Khoy Ridge, Yugra Peninsula, Russia) are presented. The mineral is...     

Graphite of the Turgenevskoe and Tamginskoe deposits of the Lesozavodsk area in the Primor’e region

The regional carbonization of the Riphean metamorphic complexes is discussed using as an example the Tamginskoe and Turgenevskoe graphite deposits located in the northern part of the Khanka terrane. It is shown that the noble metal mineralization associates closely with the graphitization. Isotopic, X-ray, and thermal analyses and Raman spectroscopy were first used for investigating the structural state of the graphite with defining its two varieties. The first of them is represented by nanocrystalline fluidogenic graphite that was formed during gas condensate crystallization from deep-seated reduced ore-bearing fluid. The second variety (large-flake graphite) represents a product of metamorphic recrystallization of carbonaceous terrigenous protoliths. The recrystallization was accompanied by the granitization of the sedimentary protolith, mobilization, and the transfer of the carbonaceous and ore matter of the host rocks. It is inferred that the graphitization associated with noble metal mineralization is a polygenic process. The graphite of the first generation associates closely with amorphous diamond-like carbon. This unexpected find may bear genetic information useful for geological and geochemical reconstructions.     

Find of anisotropic carbonic matter on a curve-faced diamond crystal

The study focuses on the identification and investigation of crystal-optical anisotropy phenomena observed on surfaces of a curve-faced diamond crystal found in alluvial sediments of the Lower Us’va River in Perm territory. Raman spectroscopy and atomic force microscopy show that interference of polarized light reflected from the tetrahexahedral faces of the diamond crystal is inspired by anisotropic carbonic matter, which appears as a film with graphene or nanographite structure and about 4 nm in thickness. The data allow us to suggest the formation conditions of curve-faced diamond crystals and origin of nanocrystalline carbonic matter on their faces.     

Conditions of the Formation of Unique Mineralization with Yushkinite V1 – xS · n[(Mg,Al)(OH)2] in Quartz–Calcite Veins,Pai-Khoi Ridge: Evidence from Study of Fluid Inclusions

Doklady Earth Sciences - The results of the study of fluid inclusions in quartz from quartz–calcite veins with unique yushkinite mineralization are reported. For the first time, it was proved...