The first discovery of oxyborates in the rocks of the Norilsk-1 intrusion (northwest of the Siberian platform)

Abstract

We found five boron minerals in the taxitic gabbrodolerites near the upper contact of the Norilsk-1 ore-bearing intrusion. These are kotoite Mg3(BO3)2, suanite Mg2B2O5, warwickite (Mg,Ti,Fe,Cr,Al)2O(BO3), ludwigite (Mg)2Fe3+O2(BO3), and azoproite (Mg,Fe2+)2(Fe3+,Ti,Mg)O2(BO3). This is the first discovery of oxyborate minerals in the Norilsk province. They form monomineral and polymineral inclusions in olivine grains from the recrystallized areas of the taxitic intrusive rocks. Boron minerals arose at the late stage of the magma crystallization or just after that as a result of the interaction of the rock with the boron-bearing fluid containing in the ore-bearing magma. Presence of the micro inclusions of the oxyborates as well as higher boron content in rocks can be used as a criterion for searching of the Pt-Cu-Ni-bearing intrusions in the Norilsk province.