Weathering

Weathering is the breaking down of rocks and other materials on the earth’s surface

In other words, Weathering is when rocks are broken into soil, sand, and sediment (tiny pieces or particles).

Weathering involves two processes that often work together to decompose or break down rocks.

What are 2 Types of Weathering?

Chemical & Mechanical Weathering

Chemical weathering, or decomposition, takes place when some of the rock’s minerals are changed into different substances.

Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation.

Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation.

Plant acid?

Lichens such as these growing on the rocks in the picture can produce weak acids that react with the rock.

Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation.

Acid rain…what is the cause?

How acid rain forms…

What causes it?

What are the effects?

Acid Rain 1908 to 1969 Acid rain has eaten away this limestone statue.

3000 year old Egyptian Obelisk 3000 year old Egyptian Obelisk after 100 years in NY

on/site_students/acid_anim.html on/site_students/acid_anim.html

Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation.

Oxidation…what is it?

Oxidation reactions involve a increase in oxidation state--in other words, the transfer of electrons from a compound that is oxidized to the compound that oxidizes it. Oxygen gas is a major component of Earth's atmosphere and is fairly reactive--so much so, in fact, that it's good at combining with metals and compounds in minerals, oxidizing or "rusting" them.

Huh??

the interaction between oxygen molecules and all the different substances they may contact oxygen

Oxidization Oxidation turned these rocks in Nevada's Valley of Fire red.

Chemical processes that cause weathering Dissolution- Soluble compounds such as limestone are dissolved. This often forms caves. Acid dissolves minerals in rocks (examples: carbonic acid, acid rain and plant acid) Acid rain can weaken rocks, corrode metal and even kill trees. Oxygen combines with iron minerals and sulfur minerals changing the composition of the rock and forming rust. This is called oxidation.

Dissolution-forming caves?

Easy answer…when rain water seeps into the ground and dissolves the limestone underneath.

Linville Caverns, North Carolina