Rocks

The foundation of Earth

What is a rock?

• Rock= A naturally occuring mixture of minerals that constitutes a significant part of Earth’s crust.

• Rocks form Earth’s hard surface

Rocks are everywhere!!!

3 Major Groups of Rocks.

• Rocks are divided into 3 main groups based on how they form!!!

• A) Igneous Rocks

• B) Sedimentary Rocks

• C) Metamorphic

Igneous Rocks

• Form from the cooling of molten rock (volcanic activity).

• Referred to as the “Parent Rock” because igneous rocks where the first rocks on Earth and gave rise to the other groups.

Types of Igneous Rocks

• There are 2 types of igneous rocks:

• Extrusive Igneous rocks= form from lava (outside of the volcano/above ground)

• Intrusive Igneous rocks= form from magma (inside volcano/below the ground)

Extrusive and Intrusive Igneous Rocks

Sedimentary Rocks!!!

• Forms when particles of other rocks and/or the remains of plants and animals are pressed and cemented together.

• After sediment has been deposited, the process of compaction (pressing) and cementation (gluing) change the sediment into rock (takes a long time!!!).

Sediment to Rock!!

3 Types of Sedimentary Rocks

• A) Clastic= contains only rock fragments squeezed together

• B) Organic= contains rock fragments AND once living plant/animal remains.

• C) Chemical= form when a liquid dissolves and leaves mineralized crystals behind.

3 Types of Sedimentary Rock

Clastic Sedimentary Rock

Organic Sedimentary Rock

Chemical Sedimentary Rock

Metamorphic Rocks

• Formed when an existing rock is changed by HEAT, PRESSURE and CHEMICAL REACTION.

• Formed (mainly) deep underground- because that’s where a rock will experience the must heat and pressure.

• Most metamorphic rocks tend to be dull in color and luster.

Metamorphic Rocks!!

Rocks, Rocks Everywhere!!!!!

The only difference in the 3 types of rocks is HOW THEY ARE FORMED!!!!!

The Rock Cycle

•A series of processes that changes rocks from one type to another.

**runs on melting & cooling, weathering, and heat & pressure.

***Any rock can be changed to any other kind of rock if/when exposed to certain elements.