Definition of ultramafic in English:

ultramafic

adjective

Geology
  • Relating to or denoting igneous rocks composed chiefly of mafic minerals.

    Compare with ultrabasic
    • ‘Both Wadi Sikait and Regal Ridge classify as Type I emerald deposits, where Be-bearing quartz or pegmatite veins from a granitic pluton intruded Cr- or V-bearing mafic or ultramafic rocks.’
    • ‘The provenance of the feldspar-bearing Crocker Formation and younger sandstones indicates a granitic source character, which conflicts with the abundance of mafic and ultramafic basement rocks exposed throughout much of Sabah.’
    • ‘Despite the attention it has received, however, the tectonic setting of the high grade mafic and ultramafic rocks of the Cabo Ortegal Complex has remained uncertain.’
    • ‘Variably serpentinized Devonian mafic and ultramafic intrusive rocks occur in the western and northern parts of the map area.’
    • ‘A major source of iron, called iron laterite, is a type of residual deposit generated by the intense weathering of iron-rich rocks such as mafic and ultramafic volcanic rocks.’

Pronunciation:

ultramafic

/ˌəltrəˈmafik/