ERGC Olivine Field Trip

August 24, 2019
10:00 AM - 1:00 PM
 Add to Calendar

Acme General Store
2035 Valley Hwy
Acme, WA 98220
 Directions

The group will be meeting at the Acme, WA general store.   Please carpool as parking is limited at both the general store and at the field trip location.  

 

Dunite - Igneous Rocks

Dunite is an ultramafic plutonic rock that is composed almost exclusively of olivine.. “Ultramafic” means that mafic minerals form more than 90% on the rocks composition.

it is a slight yellowish green, intrusive igneous ultramafic rock that is composed almost entirely of olivine. Dunite usually forms sills (tabular bodies intruded between other rocks) but may also occur as lenses (thin-edged strata) or pipes (funnels, more or less oval in cross section, that become narrower with increasing depth). It is a common rock in Earth’s upper mantle. Occurrences include Dun Mountain, New Zealand, from which the rock takes its name; the Bushveld Igneous Complex, South Africa; and Frostviken, Jämtland, Sweden. Chromite, picotite, and magnetite also occur in dunite, as do spinel, ilmenite, pyrrhotite, and platinum in some cases. Dunites constitute an important source of chromium, a commercially valuable metal.