1. Education

Eclogite

Pictures of Metamorphic Rock Types

Eclogite ("ECK-lo-jite") is an extreme metamorphic rock, formed by regional metamorphosis of basalt under very high pressures and temperatures. (more below)
From very deep subduction
Photo (c) 2005 Andrew Alden, licensed to About.com (fair use policy)
Click the photo to see the larger version. This eclogite specimen from Jenner, California, was part of a subducting plate during Jurassic times, about 170 million years ago, when it formed. Much more recently, during the last few million years, it was raised and mixed into younger subducted rocks of the Franciscan complex. The body of eclogite is no more than 100 meters across today. It consists of high-magnesium pyrope garnet, green omphacite (a high-sodium/aluminum pyroxene), and deep-blue glaucophane (a sodium-rich amphibole).

For more photos see the Eclogite Gallery.

Other galleries:
Fossils
Geologic Features and Processes
Glaciers and Ice
Landforms
Minerals
Rocks
Geology and Society

©2013 About.com. All rights reserved.