Geochemical features of Malyutka ore-bearing massif rocks, Khudolaz complex, South Urals: evidence of hydrothermal reprecipitation of siderophile and chalcophile elements

Hydrothermal processes play an important role in the reprecipitation of ore elements, but it is difficult to characterize their qualitative and quantitative parameters for large objects. The compact homogeneous internal structure of the ultramafic massif Malyutka of the Khudolaz differentiated complex provides a good opportunity to characterize the features of the hydrothermal reprecipitation of mobile elements in it. The geochemical features of barren and ore-bearing variously altered rocks of the Malyutka massif have been studied using the methods of X-ray fluorescence (XRF) and mass spectrometry with inductively coupled plasma (ICP MS) analyzes. The results show a strong depletion of ores by siderophile (Ni, Co) and chalcophile (S, Cu, As, Se, Cd, Bi, Pb and many others) elements under hydrothermal influence, which is consistent with the postmagmatic dissolution and replacement of sulfide minerals not only by secondary sulfides, but also silicates. Leaching led to a reprecipitation of these elements, mainly to dispersion, both inside the intrusion and outside it. Most lithophile macro- and microelements have not reprecipitated significantly in hydrothermal conditions.