lamprophyre (Scotland). Kimberlite pipes in Canada, Russia and South Africa have incompletely preserved tephra and agglomerate facies. These are generally diatreme events and as such are not lava flows although tephra and ash deposits are partially preserved. These represent low-volume volatile melts and attain their ultramafic chemistry via a different process than typical ultramafic rocks. Metamorphic ultramafic rocks Metamorphism of ultramafic rocks in the presence of water and/or carbon dioxide results in two main classes of metamorphic ultramafic rock; talc carbonate and serpentinite. Talc carbonation reactions occur in ultramafic rocks at lower greenschist through to granulite facies metamorphism when the rock in question is subjected to metamorphism and the metamorphic fluid has more than 10% molar proportion of CO2 (carbon dioxide). When such metamorphic fluids have less than 10% molar proportion of CO2, reactions favor serpentinisation, resulting in chlorite-serpentine-amphibole type assemblages. Distribution in space and time The majority of ultramafic rocks are exposed in orogenic belts, and predominate in Archaean and Proterozoic terranes. Ultramafic magmas in the Phanerozoic are rarer, and there are very few recognised true ultramafic lavas in the Phanerozoic. Many surface exposures of ultramafic rocks occur in ophiolite complexes where deep mantle-derived rocks have been obducted onto continental crust along and above subduction zones. Soil and regolith on ultramafic rock Serpentine soil is a magnesium rich, calcium, potassium and phosphorus poor soil that develops on the regolith derived from ultramafic rocks. Ultramafic rocks also contain elevated amounts of chromium and nickel which may be toxic to plants. As a result, a distinctive type of vegetation develops on these soils. Examples are the ultramafic woodlands and barrens of the Appalachian mountains and piedmont, the "wet maquis" of the New Caledonia rain forests, and the ultramafic forests of Mount Kinabalu and other peaks in Sabah, Malaysia. Vegetation is typically stunted, and sometimes includes endemic species adapted to the soils. Often thick, magnesite-calcrete caprock, laterite and duricrust forms over ultramafic rocks in tropical and subtropical environments. Particular floral assemblages associated with highly nickeliferous ultramafic rocks are indicative tools for mineral exploration. Weathered ultramafic rocks may form lateritic nickel ore deposits. Other celestial bodies Io Ultramafic lava may have been detected on Io, a moon of Jupiter, because heat-mapping of Io's surface found ultra-hot areas with temperatures in excess of . The magma immediately below these hot spots is probably about hotter, based on surface-to-subsurface temperature differences observed for lava on