The chemical and mineral composition of volcanic ash in the Upper Carboniferous deposits of the Usolka section (South Ural, Russia)

© 2020 IOP Publishing Ltd. All rights reserved. Volcanic ash from the Usolka section, which is proposed as an international standard for global correlation of the lower boundaries of the Kasimovian and Gzhelian Stages, is considered. The content of rock-forming components in ashes is given. It is shown that the ashes of the Gzhelian Stage differ from older deposits in higher contents of Al, Ca, Mn and lower contents of Si, Ti, Fe. An increase in the content of some microcomponents (Cu, Cr, Ba, S) to the lower boundary of the Kasimovian Stage was noted. For the first time, information has been obtained on the mineral composition of ashes, which allows them to be used for correlation

Iron-Nickel Microparticles in the Sedimentary Rocks as Indicators of Cosmic Processes

The microstructure, chemical and mineral composition of iron-nickel microparticles from the sedimentary deposits of the Peri-Caspian Depression were studied. It was found that the microspheres developed as a result of the fractional condensation of a Fe-Ni melt and its crystallization at the early stage of the evolution of the substance of the protosolar nebula. Upon reaching the atmosphere of the Earth, these microspheres undergo changes in terms of partial oxidation of magnetite to hematite and native nickel to nickel oxides, melting of fusible metals in the core part, and atmospheric entry under the influence of the “pulverization effect” resulting in the development of awaruite microparticles of various shapes. The obtained data are most likely to prove the extraterrestrial origin of Fe–Ni microparticles and their relation to the fallings of cosmic bodies on the Earth in the geological past