Acidic Lower Cretaceous subvolcanic and volcanic formations of the North Argun Depression

Abstract

In the complex history of Mesozoic magmatism and ore formation in the Eastern Transbaikalia, the latest stages of the history, associated with the formation of numerous linearly elongated depressions of northeastern strike, are the least studied. They are bordered by large faults and are filled with Late Mesozoic sedimentary and volcanogenic rocks. It is to the depressions that the areas of the strongest manifestation of young tectonic movements and manifestation of the latest magmatic formations gravitate. Accordingly, the latest manifestations of hydrothermal mineralization in the Eastern Transbaikalia are closely related to depressions themselves or to the systems of discontinuities surrounding them (gold deposits of the Baley type, deposits of fluorspar, ferberite-antimony-nite ores of the Barun-Shivey type, ore occurrences of antimonite, cinnabar, barite, etc.). The overwhelming majority, if not all these ore occurrences, belong to the type of low-temperature hydrothermal formations of shallow depths. Both the source of this mineralization and its age are still disputable. However, in recent years the opinion has been expressed that this mineralization is related to the Lower Cretaceous volcanogenic complexes. Therefore, it is very important to study the history of Lower Cretaceous volcanism of the Eastern Transbaikalia, in particular, to investigate various subvolcanic, vent, etc. formations, since in a number of geologically similar areas their location largely determines the peculiarities of mineralization placement ...