complexe ultramafique

CONT: Les participants à la conférence de Penrose en 1972 [...] ont défini le terme «ophiolite» comme étant un assemblage distinctif de roches mafiques à ultramafiques qui comprend, de haut en bas 1) un complexe ultramafique consistant en proportion variable d'harzburgite, de lherzolite et de dunite ayant habituellement une fabrique tectonique, 2) un complexe gabbroïque à texture de cumulats [...], 3) un complexe de dykes, 4) un complexe de roches volcaniques généralement en coussin.
OBS: complexe ultramafique : terme en usage à Ressources naturelles Canada - Secteur des sciences de la Terre.

CONT: Typical ophiolite sequences are comprised of a thin layer of deep-sea sediments, overlying a sequence of basaltic pillow lavas, sheeted dike complexes, foliated to layered gabbro, and finally an ultramafic complex, which can have an exposed thickness of up to 7 km. This ultramafic section of ophiolite sequences can vary in composition; however, it is most commonly dominated by varieties of peridotite typically associated with the mantle such as harzburgite (olivine and orthopyroxene rich), and lherzolite (olivine, ortho- and clinopyroxene rich), with secondary wehrlite (clinopyroxene and olivine rich) and dunite (olivine rich) ...
OBS: ultramafic complex: term used at Natural Resources Canada - Earth Sciences Sector.