Abnormally high content of noble metals in wastes of the Fiagdon concentration plant: a possible new type of mineralization for the North Caucasus is gold-platinoid with base metals, localized in the Early-Middle Jurassic black shales

Abstract

Relevance. In the North Caucasus noble-metal (gold, silver, platinum, elements of the platinum group (PGE)) mineralization of the black-shale type is localized in Toar-Aalenian flysch-like organic matter rich, terrigenous sediments in the regional (from Dagestan to Adygea and Krasnodar Territory) Samuro-Belorechenskaya metallogenic zone (SBMZ). Involvement in prospecting and exploration of this strategic type of mineralization provides the opportunity to expand the mineral resource base of the Southern Federal District of Russia. The Aim of the research is to identify the content of platinum and PGE in the industrial wastes of the Fiagdon concentration plant (FCP) and in the ore-bearing Toar-Aalenian black shale strata. In particular, processed ores of the Kadat and Kakadur polymetallic deposits, localized in Avsandur-Lamardon ore field (ALOF). The ALRP was prospected for economic gold-platinum with polymetallic deposit in the black-shales series. Methods. ICP-MS analysis – 5 samples were analyzed by ICP-MS in IGEM-Analytics Center on an X-Series II mass spectrometer and 13 samples – in the Laboratory of Physical-Chemical and Chemical Methods of Analysis of the IMGRE on the Elan 6100 DRC instrument. Results. The elevated noble metal concentrations established in 18 samples (borehole core samples) from the Fiagdon tailings dump could be explained by the presence of both the ALRP ores and the gold-platinum with polymetallic mineralization in the host Toar- Aalenian black-shales series (2.5-3.2 wt. % of carbonaceous matter). The model of formation of gold-platinum mineralization at the expense of vadose water convection in highly metalliferous (Au, Ag, Pt, Pd) Early-Middle Jurassic flysch-like strata of siltstone-argillite composition is proposed. During prospecting works for gold-quartz, gold-sulfide and colliery-polymetallic with gold types of mineralization in the Mountain Ossetia and in the eastern part of Mountain Dagestan a number of promising objects for gold were revealed. A number of economic significant objects with gold-platinum with polymetallic mineralization in black-shale series of Toar-Aalenian age can be identified within the SBMZ. A complex of prospecting with minimal time, material and financial expenses is proposed.