A Brief Case Study on Weathering of Granite!

Dartmoor and Isle of Arran is the perfect example that exhibits an elegance of granite in its natural form. As we all know that granite is formed due to the intrusion of magma into the pre-existing layers of the rocks and then with the passage of time due to cooling and pressure inside the earth produced the crystals of quartz, mica, feldspar and silica that ultimately lead to the formation of granite rock. All the naturally formed tor of granite on earth is basically the result of weathering process.

Types of weathering process in Granite!

There are basically two types of weathering process in granite namely;

1.       Frost shattering

It is also known as physical weathering that result into the disintegration of the granules. It happens due to the number of freezing cycles which basically causes the expansion and thawing of water on granite’s joints in continuous manner.

2.       Hydrolysis

It is another weathering process in granite which is also known as chemical weathering. This process of hydrolysis indirectly causes the phenomenon of Kaolinisation under which kaolin or china clay is produced when feldspar’s crystals gets dissolve in granite through hydrogen. This phenomenon remains active till the granite is exposed in good amount of water. This hydrolysis of granite basically makes the granite weak as it is strengthen material quartz remains as loose crystal.

If you want to see the fine example of weathered granite then landscape of Dartmoor is best place to see as it is mostly composed of granite and its been formed about 280 millions years ago. If you take a look on the landscape of South Britain then you will see that Dartmoor is the largest area displays good amount of granite.

Whenever you see granite landscape then you will find that TORS are their speciality that are formed due to the weathering processes and one such example is Hound Tor in Dartmoor. There are several theories that are developed on the formation of Tor but here are a few points of one of the theory that can describe you its formation easily:

1.       Initially vertical joints were formed due to cooling and contractions then horizontal joints were formed due to the weathering of upper layer of rocks that helped in releasing the inner pressure of granite and caused its expansion.

2.       Hydrolysis and Kaolinisation are the two processes that helped in widening these joints followed by deep weathering of granite rocks that finally give the birth to TORS.

You can find a lot of such topics on granite's origin, quarries, granite architectures and installation and maintainence of granite worktops on my latest blog at http://www.granite4less.co.uk/blog/