Rudenko K. Geology and metal-bearing of the Ratno Beds in Rafalivka field (Chartorysk fault zone)

Українська версія

Thesis for the degree of Candidate of Sciences (CSc)

State registration number

0415U002185

Applicant for

Specialization

  • 04.00.01 - Загальна та регіональна геологія

14-05-2015

Specialized Academic Board

Д26.162.02

Essay

Urgent task of the Ratno Beds (Lower Vendian, Upper Proterozoic) geological and tectonic structure within Rafalivka ore area (Chartorysk fault zone) and its metal-bearing feature were solved. The systematization of modern views about the flood basalt formation of Rafalivka area (Chartorysk fault zone), which is a part of the Volhyn-Podillia plate, was carried out. The main geological and tectonic features of the Ratno Beds (Lower Vendian, Upper Proterozoic) within Rafalivka area (Chartorysk fault zone) were identified. The geological and structural data analysis allowed to assign the sub-latitudinal zone of the rocks significant disintegration, which does not coincide in time with the activation of the Chartorysk fault zone north-western liniaments, and was formed in after-Lower Vendian time during the re-activation of the area. It was determined that the top of each basalt flow is characterized by: rocks disintegration, high amount of amygdales and horizontal veinlet, distribution of montmorillonite (kaolinite), carbonate, opal and high content of iron hydroxides. Those are evidences of the tectonics process and time break between effusions. Conducted mineralogical mapping of basalt flows made possible to distinguish two groups of secondary alterations: regional and local. The isolated local zones of quartz-carbonate-sulphide mineralization in the middle of basalt flows, which tend to zones of brecciation and fracturing (fine-grained mineralization by thin veinlets composed of quartz, calcite, iron and copper sulphides, rare - sericite, barite, epidote) were found. These zones are confined with the local zones, which are characterized by the elevated concentrations of silver, gold, mercury, lead and barium. The temperature of mineral forming process in this zone corresponded to the low-temperature hydrothermal later stage. Morphogenetic diversity of native metals mineralization (Rafalivka area) was characterized and highlighted two main types: 1) chemically heterogeneous polycrystalline aggregates, which form primarily of macro- and micro-inclusions (nuggets of copper and iron, rare - of silver, in the form of dendrites, films etc.); 2) dispersed native metals particles, which form micro- and nanoinclusions in rock matrix. A comparative analysis of deposits and occurrences of native copper reveals a general typical features: 1) a source of copper in the ore process is enclosing volcanic rocks mainly of basaltic composition, in some cases, andesites; 2) increase (change) of native copper concentrations and the associated mineralization occurred after the volcanic strata formation and continued for a long time; 3) the rocks underwent intense tectonic, medium- and low-temperature hydrothermal alteration; 4) the presence of organic matter (bitumen mineralization) caused reducing feature of fluid solutions; 5) formation of epithermal noble metal mineralization associated with the latest activation of territory.

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