Mineral associations of soils located in mountainous tundra derived from and underlain by ultrabasic rocks
using the example of the Polar Urals were studied. Key plots are located on a flat summit and a slope of the
Rai-Iz massif where ultrabasic rocks are represented by a dunite - harzburgite complex and the Rai-Iz massif,
on a moraine ridge consisting mostly of basic material with admixtures of ultrabasic rocks.
The mineral association in all studied sola is a result of (i) disintegration of easy weathering ultrabasic rocks
that are a source of olivine, pyroxenes, serpentine, talc, and chlorite; (ii) influence of allochthonous material
enriched by quartz and feldspars; and (iii) pedogenic neoformation and decomposition of saponite; and (iv)
development of iron (hydr)oxides in micro-cracks of olivine, pyroxenes, and serpentine and fragments of
plant tissues. Clay minerals associations in sola are determined by resources of ultrabasic rocks even in case
of mixture of ultrabasic and basic rocks when the latter are predominant. The acidic effect of moss and
lichens seems to be a reason for selective decomposition of the most unstable minerals despite the pH value
of bulk samples.