1. Types of Rock Liz LaRosa http://www.middleschoolscience.com 2010
Images from Geology.com unless otherwise noted

2. Earth’s Layers

3. What are Rocks?
A rock is a naturally occurring solid mixture of one or more minerals, or organic matter
Rocks are classified by how they are formed, their composition, and texture
Rocks change over time through the rock cycle

4. Igneous Rocks Igneous rock begins as magma. Magma can form:
When rock is heated
When pressure is released
When rock changes composition
Magma “freezes” between
700 °C and 1,250 °C
Magma is a mixture of
many minerals

5. Sedimentary Rocks Sedimentary rock is formed by erosion
Sediments are moved from one place to another
Sediments are deposited in layers, with the older ones
on the bottom
The layers become compacted and cemented together

6. Law of Superposition
This law states that the oldest rock is at the bottom, and the newest is at the top.
There are variations caused by plate tectonics.

7. Sedimentary Rock
Sedimentary Rocks are formed at or near the Earth’s surface
No heat and pressure involved
Strata – layers of rock
Stratification – the process in which sedimentary rocks are arranged in layers

8. Sedimentary Rock
More than 70% of the Earth’s crust is made of sedimentary rock
Fossils are found between the layers, or strata.
Sometimes the strata become angled or moved due to the movement of Earth’s tectonic plates.

9. Metamorphic Rock Meaning to change shape Changes with temperature
and pressure, but remains
solid
Usually takes place deep in
the Earth

10. Continental Drift
A theory that the earth’s surface is constantly in motion.
This theory also stated that at one time, all the continents were stuck together in one continent called Pangea.
The scientist who came up with it is Alfred Wegener

11. Plate Tectonics
The Earth’s curst is made of plates that move on top of the liquid mantle.
The plates meet on 3 types of faults.
Convergent move together
Divergent move apart
Transform move alongside each other