Aya Alygeo chapter 8

Aya Alygeo chapter 8 - Professor Ohan Chapter 8 1 Metamorphic rock is the transformation of an existing rock type the protolith in a process called

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Professor Ohan Chapter 8 1- Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism , which means "change in form". The protolith is subjected to heat and pressure (temperatures greater than 150 to 200 °C and pressures of 1500 bars) causing profound physical and/or chemical change. The protolith may be sedimentary rock , igneous rock or another older metamorphic rock. Metamorphic rocks make up a large part of the Earth 's crust and are classified by texture and by chemical and mineral assemblage ( metamorphic facies ). 2- They may be formed simply by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from tectonic processes such as continental collisions, which cause horizontal pressure, friction and distortion. 3- They are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides us with information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are gneiss , slate , marble , schist , and quartzite . 4- Metamorphic minerals are those that form only at the high temperatures and pressures associated with the process of metamorphism. These minerals, known as index minerals , include sillimanite , kyanite , staurolite , andalusite , and some garnet . 5- Other minerals, such as olivines , pyroxenes , amphiboles , micas , feldspars , and quartz , may be found in metamorphic rocks, but are not necessarily the result of the process of metamorphism. These minerals formed during the
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 02/05/2012 for the course GEOLOGY 101-101 taught by Professor Ohan during the Spring '11 term at CUNY City.

Page1 / 3

Aya Alygeo chapter 8 - Professor Ohan Chapter 8 1 Metamorphic rock is the transformation of an existing rock type the protolith in a process called

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online