Image taken from:
http://www.studyworksonline.com/
cda/content/article/0,,EXP888_N
AV2-77_SAR848,00.html
Minerals in Metamorphic Rocks

by

Shawn Salley

http://www.emporia.edu/earthsci/amber/go336/salley/home.htm


Table of Contents
Introduction
Contents
Minerals
Conclusion
References and Links




Introduction

Mineral crystallization occurs under specific conditions.  Those processes include growth from solutions, melts and vapors. Due to the environment and chemical elements in the parent rock, specific minerals are formed.  Metamorphism is between a total melt of solution that form igneous rocks and the deposition of sediment under a normal environment that forms sedimentary rocks.  In conditions of metamorphism, some minerals form that are not found in any other environments on earth.  Largely this is a function of phase changes associated with heat and pressure exerted on the rock.  This project will look at the fundamental properties of metamorphism and the minerals that form as its result.


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Contents

Processes of Metamorphic Rocks

East Spanish Peak
Photo by
S.W. Salley, 2001
The East Spanish Peak in Southern Colorado is a small example of contact metamorphism. The aureole of the East Peak extends approximately two miles from the zone of contact.

Areas like the Swiss Alps are effected by regional metamorphism.  The Matterhorn in the Swiss Alps is perfect for finding metamorphic minerals. Image to the left was taken from Mountainzone.com   http://classic.mountainzone.com/climbing/alps/graphics/matterhorn-sunrise.html

 

Phase Changes

Minerals


Figure taken from: http://www.uoregon.edu/
~jrice/geol_311/stability.html
.
There are three polymorphs of Al2SiO5: andalusite, kyanite and sillimanite. They are stable in all regions of pressure and temperature.  At normal atmospheric conditions, only kyanite is thermodynamically stable, but all three persist at room temperature because of kinetic laws.  

 

Figure taken from: http://www.uoregon.edu/
~jrice/geol_311/stability.html
.
There are two common polymorphs of carbon: diamond and graphite. Diamond is stable at extreme pressures. 

 


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Conclusion

Metamorphic rocks form from heat and pressure. Some of the minerals that make up those rocks also change properties as heat and pressure is applied. Polymorphs of minerals at different phases result and thus some minerals are only found in metamorphic rocks.


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This web presentation is for the partial fulfillments of Mineralogy
from Emporia State University and the Earth Science department. 

Please direct questions to the author

Copyright 2002 S.W. Salley. All rights reserved.