EARTH232 Lecture Notes - Lecture 31: Forsterite, Dunite, Guadalupe-Nipomo Dunes
26 Aug 2016
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Document Summary
The figure on the left shows a chemical analysis done on a sample of dunite from dun mountain. The major compounds are magnesium oxide and silica along with other minor compounds made of iron, chrominum, aluminum, iron, nickel and titanium. This sample was composed of olivine that was a forsterite and so there is a high magnesium content. For comparison the figure on the right shows an average composition of a basalt sample. Basalt is a mafic rock whereas dunite is ultra mafic so dunite has a lower silica content than the basalt. Dunite, since it is primarily composed of olivine makes an excellent refractory. Another use that is becoming increasingly more important is for carbon sequestration. The use of dunite as a way to absorb co2 from the atmosphere could prove to be an effective measure against global warming. Olivine as we know from bowen"s reaction series exists as a solid at high temperatures.
