The mylonitic and banded harzburgite
and dunite at the base of the ophiolite record plastic deformation developed possibly within the granulite facies (Boudier and Coleman 1981; Nicolas 1989).
Within and adjacent to the Olive Highlands, ultrabasic bedrock (harzburgite
) is found only just outside the periphery in the north-east, in upper Wadi Hayl and Wadi Saham, at elevations well below the main ridges, but some ultrabasic rock types can be found within what is mapped as a mixed unit, along the short ridge west of the Jebel Qitab summit ridge (separating uppermost Wadi Hiluw from Wadi Hayl) and continuing north along the lower slopes of the Olive Highlands, east of Jebel Sfai and Jebel Samah (British Geological Survey 2006a, Thomas et al.
J., 1990, Harzburgites
and refractory melts in the Lewis Hills massif, Bay of Islands ophiolite complex: The base-metals and preciousmetals story: The Canadian Mineralogist, v.
The Precambrian Ophiolits in north of Anarak are seen underneath the Precambrian-lower Cambrian metamorphics  and are of Harzburgite
and partly lherzolite accompanied with whom scattered masses of gabbro, Diabase, and plagiogranite are observed.
muricata may also be limited by geology, avoiding the ultrabasic rocks (harzburgite
) of the Semail nappe (a/k/a the Oman ophiolite), which comprise most of the mountainous area between the existing records.
The foliated peridotite is mainly harzburgite
with minor dunite which occurs within harzburgite
and contains podiform chromite deposits.
, dunite mantle xenoliths, and xenocrystic debris are common and abundant in the ankaratrites and nephelinites  from eastern ASV (Figure 3).
The second type recognized in the mafic-ultramafic bodies is dominated by variably metamorphosed ultramafic rocks (lherzolite, harzburgite
, wehrlite, dunite, and pyroxenite; Fig.
A key feature of the central Slave SCLM, including that of the Lac de Gras kimberlite field, is an approximately 150 km thick, conductive (Jones et al., 2001), ultra-depleted harzburgite
layer above more fertile lherzolite (Griffin et al., 1999).
Diamonds are known to occur in three peridotite subtypes: dunite (90% olivine), harzburgite
(40-90% olivine, the rest orthopyroxene and garnet), and lherzolite (at least 40% olivine, with orthopyroxene and clinopyroxene in a wide range of proportions, and minor garnet).