OFS metallogenic types and subtypes, in brackets—GSB. Age range OFS formation, million years

Pre-ore

Ore formation steps

1

2

3

1

3

4

5

6

Iron ore Baikal-Patom

1580-927

Orthoamphibolites, partially granitized

Chlorite-actinolite-albite-epidote, plagioclase-actinolite-chlorite, quartz-chlorite-sericite-carbonate dynamoslates with hematite- magnetite mineralization

Pyrite-polymetallic (Tiya-Ollokit).

1500-550

Orthoamphibolites, serpentinites

Graphite-garnet-quartz-double mica, graphite-carbonate- quartz-mica dynamoslates with strata-like deposits of quartz-sphalerite-galenite ores

Dynamometamorphic metasomatites, hydrothermalites of plagioclase-muscovite and quartz-muscovite composition with veinlet-disseminated polysulfide mineralization