Mafic and Ultramafic Inclusions in Igneous Rocks
Mafic and ultramafic inclusions in igneous rocks have for a long time stimulated the interest of geologists and petrologists with peridotite inclusions with ovoidal shape ("olivine nodules") having been studied for more than a century. At first, the interest was the result of the striking contrast of color, mineral assemblage, and texture between the inclusion and host rock, but now a major reason for their study arises from at least some of them being representative of mantle source material for melts of mafic and ultramafic composition. The physical, chemical, and mineralogical properties of these inclusions appear to remain within the geophysical and petrological constraints on the rock types of the upper mantle. Other inclusions consist of minerals and monomineralic or polymineralic rocks (igneous, sedimentary and metamorphic).
Both the presence and abundance of inclusions in igneous rocks are controlled by the extent of stoping of