Rocks & Minerals

The LITHOSPHERE is a rigid structure that is made up of the Earth’s crust and part of the upper mantle

It is between 70km and 150 km thick

It contains minerals the plants need

It contains several important natural resources

Recall: Lithosphere

What is the difference

between rocks and

minerals?

•Mineral: solid, inorganic (non-living), pure(homogeneous) substance which:•Occurs naturally

•Has an ordered atomic structure which forms crystals

•There are 4000 known minerals on Earth

Minerals

•Gold – used in jewellery

•Sodium chloride – table salt

•Beryllium – found in emeralds

•Pyrite – known as fool’s gold; used in alcohol preservation

Commonly used minerals

•The inner shape of minerals consists of crystals; these are different for different minerals and are often used in their identification

Crystal Structure

Crystal Structure

•We rarely find minerals in their pure form•They need to be mined and extracted from rock•When precious minerals are extracted from the lithosphere they are called ore

•Ore: a rock containing a mineral that is mined for profit (See page 303 in textbook)

Ore

•Rocks: are a collection of different minerals•A mixture(heterogeneous blend)

•They are highly compacted and formed through various geological processes

Rocks

•Pure substance:•A substance made of all the same types of atoms or molecules•Only one type of particle

Pure Substances vs Mixtures

•Mixture:•Two or more substances that are NOT chemically combined

Pure Substances vs Mixtures

Mixture or Pure Substance?

Pure substance Mixture Pure substance

•Heterogeneous mixture

•A mixture where you can clearly see the different particles

Heterogeneous vs Homogeneous

•Homogeneous mixture•A mixture of substance that looks uniform (all the same)•You cannot see the difference between the particles

Heterogeneous vs Homogeneous

Heterogeneous Mixtures

•A mixture of substances where you can clearly see the different particles

Homogeneous Mixtures

•A mixture of substance that looks uniform•You cannot see the difference between the particles

Types of Rocks

•There are 3 types of rocks:•Igneous•Sedimentary•Metamorphic

•Igneous rock is formed by magma(molten rock) being cooled and becoming solid

Igneous rock

•Makes up approximately 90% of the Earth’s crust

•There are 3 types of igneous rock:

•Intrusive igneous rock

•Extrusive igneous rock

•Porphyritic igneous rock

Igneous Rock – 3 Types

Igneous Rock – Intrusive

Intrusive (or Plutonic) Igneous Rock•Slow cooling of magma within the Earth’s crust

•Has large crystals

•Example: Gabbro

Igneous Rock – Extrusive Igneous

Extrusive or Volcanic Rock•Formed when lava cools in contact with air or water

•Has microscopic crystals

•Example: Obsidian

Igneous Rock – Porphyritic Igneous

Porphyritic•Undergoes two cooling phases

•Crystals vary in size

•Example: Certain types of Granite

Basalt – a fine-

grained extrusive

igneous rock

Granite – a coarse-

grained intrusive

igneous rock

Intrusive – rocks made by

the freezing of magma

underground.

Extrusive – rocks that

form above ground, after

lava spills out and

extrudes on the surface

of the Earth.

RECAP

Slide taken from a ppt entitled week 6 2011 from http://eps.mcgill.ca/~courses/c201_winter/

•Created by pressure compacting sediment (small particles being carried away from erosion)•Create layers

•They may preserve signs of life and surface activity:•Like fossils, tracks, ripple marks, etc.

Sedimentary rock

Sedimentary rock

•Rock that has been trapped under the Earth’s crust for a LONG time• The heat and pressure causes the rock to transform

• Ex: slate, marble, schist

•Come in a lot of different colours

•Often see signs of stretching or squeezing (ex: stripes)

Metamorphic rock

Metamorphic rock