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Chemical Weathering

Chemical weathering is the wearing down of rock by chemical reactions. In this process the rock's minerals are changed into finely divided products that can easily be carried away. Air and water are involved in the many complex chemical reactions, which include

Igneous minerals are unstable under normal atmospheric conditions, those formed at higher temperatures being more readily attacked than those formed at lower temperatures. Igneous minerals are commonly attacked also by water, particularly acid or alkaline solutions. All the common rock-forming igneous minerals (except quartz, which is very resistant) are changed in this way to clay minerals and chemicals in solution. Silica is leached from silicate minerals and removed as a colloidal material that can be deposited later as opal or chert. Clay, quartz, colloidal silica, and chemicals in solution - the common products of weathered rocks - are the building materials of the sedimentary rocks.


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Image from: NOAA

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Chemical Weathering

Chemical weathering is the wearing down of rock by chemical reactions. In this process the rock's minerals are changed into products that can easily be carried away. Air and water are involved in the many complex chemical reactions which are possible.

First, minerals of igneous rock can be attacked by molecules of the atmosphere, particularly oxygen. Minerals of igneous rock are attacked also by water, particularly acid or alkaline solutions which are part of the water. Silica is leached from silicate minerals and removed. All the common igneous minerals (except quartz, which is very resistant to erosion) are changed in this way to 1) clay minerals or 2) freely floating chemicals such as chlorine.

Clay, quartz, silica, and freely floating chemicals - the common waste products of eroded rocks - are the building materials of the sedimentary rocks.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks


Chemical Erosion

Chemical erosion is the wearing down of rock by chemical reactions. In this process the rock's minerals are changed into waste products that can easily be carried away. Air and water are involved in the many chemical reactions which are possible.

First, minerals of igneous rock can be attacked by molecules of the atmosphere, particularly oxygen. Minerals of igneous rock are attacked also by water, particularly acids which are part of the water. Silica is leached from silicate minerals and removed.

The minerals are changed to 1) clay or 2) freely floating chemicals such as chlorine. These waste products are the building materials of the sedimentary rocks.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks




Last modified January 26, 1999 by the Windows Team

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