1. Rocks and the Rock Cycle
Earth Science – Competency Goal 1.02

2. Rocks and Rock Cycle – Three Major Types
Three major Rock types.
Igneous
Sedimentary
Metamorphic

3. Rocks and Rock Cycle – Igneous
Igneous – Latin Term – “From Fire”
Igneous rocks form when magma cools and hardens.
Magma is called lava if it cools at the Earth’s Surface
2 major types Igneous
Intrusive – Magma forms and intrudes rocks beneath the Earths surface
Extrusive – The rapid cooling of magma at the Earth’s Surface.

4. Rocks and Rock Cycle – Igneous
Mineral Composition –
Granite Family (Felsic) Rich in silica.
Basalt Family (Mafic) Rich in iron.
Texture – Extrusive
Fine grained minerals – cool quickly, Pumice
No mineral composition - Obsidian
Texture - Intrusive
Large minerals – cools slowly beneath the Earth and then more rapidly as it nears the surface – Granite. Page 178

5. Rocks and Rock Cycle – Sedimentary
Sedimentary – Compaction and cementation are the process behind the formation of this rock type.
Clastic – separate fragments of rocks are compacted to form one.
Chemical – forms from minerals that have dissolved in water over time
Organic – forms from the remains organisms- limestones, coal, fossils.
Features – stratification, layering, ripple marks, mud cracks, salt casts.

6. Rocks and Rock Cycle – Metamorphic
Rocks deformed from heat, pressure, and hot fluids can certain minerals to change into other chemicals.
Types of Metamorphic Rocks.
Unfoliated rocks no banding
Foliated Rocks formed with a banding look – alternating dark and light bands.
Extreme pressure will flatten them
Different density will sort minerals