Ultramafic rock

A ultramafitite or ultramafic rock is an igneous rock, which consist of 90 percent by volume or more of mafic minerals, ie its color index M> 90. The rock may be monomineralic or of several mafic minerals such as pyroxenes, amphiboles, olivine, inter alia, exist in varying proportions. The olivine of the ultramafics can be transformed into serpentine. Usually the term is also applied to metamorphic rocks that have emerged from igneous rocks and comply with this criterion.

The naming of Ultramafititen is QAPF or Streckeisen diagram not possible due to the extremely low share of there considered minerals. Therefore, it is classified according to schemes that are based on the above mafic minerals.

Examples of plutonic Ultramafitite are dunite (only olivine ) pyroxenite ( pyroxene only ) hornblendite (only hornblende ), glimmerite (only mica), peridotite ( pyroxene and olivine ), and lherzolite ( pyroxenes and olivine ).

Examples of volcanic Ultramafitite are Melilithit, Pikrit and komatiite.

In Ultramafititen often are fragments of the mantle, which passed through geological processes of the earth's surface, such as the Olivinbomben the Eifel or rock shed in orogens ( ophiolites ). Also, due to collection of early Kristallisaten the bottom of a magma chamber, it may come to the formation of Ultramafititen (eg, harzburgite ), where they can make significant deposits by accumulation of ore minerals (eg Chromitite ).

Although not synonymous, but the terms ultramafic rocks and ultrabasic rocks are often used interchangeably, incorrectly, used.

Types of natural stone

Ultramafitite be used as decoration or as grave stones in the natural stone sector. Well-known varieties are the Solwark ( peridotite from Norway) and the Poschiawo ( serpentinitisierter peridotite from Switzerland ).