Definition of ultramafic in English:

ultramafic

Pronunciation /ˌəltrəˈmafik/ /ˌəltrəˈmæfɪk/

adjective

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

    ‘Variably serpentinized Devonian mafic and ultramafic intrusive rocks occur in the western and northern parts of the map area.’
    Compare with ultrabasic
    • ‘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.’
    • ‘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.’
    • ‘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.’
    • ‘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.’