Eclogite

Accessory minerals include kyanite, rutile, quartz, lawsonite, coesite, amphibole, phengite, paragonite, zoisite, dolomite, corundum and, rarely, diamond.

[10][3] Models proposing a primary surface origin as seafloor protoliths strongly rely on the wide range in oxygen isotope composition, which overlaps with obducted oceanic crust, such as the Ibra section of the Samail ophiolite.

[11] This process is attributed to both low- and high-temperature seawater exchange, resulting in large fractionations in oxygen isotope space relative to the upper mantle value typical of mid ocean ridge basalt glasses.

[13][14] Other mechanisms proposed for the origin of Group A eclogite xenoliths rely on a cumulate model, where garnet and clinopyroxene bulk compositions derive from residues of partial melting within the mantle.

Eclogites containing lawsonite (a hydrous calcium-aluminium silicate) are rarely exposed at Earth's surface, although they are predicted from experiments and thermal models to form during normal subduction of oceanic crust at depths between about 45–300 km (28–186 mi).

[21] Transitional granulite-eclogite facies granitoid, felsic volcanics, mafic rocks and granulites occur in the Musgrave Block of the Petermann Orogeny, central Australia.