Module 1 - rocks, minerals and the rock cycle

Question 1

What are the two types of silicate minerals and their properties?

Answer 1

1. Felsic-They are richer in silicates, less dense, and lighter in color. e.g Quartz
2. Mafic-they are rich in magnesium and iron but low in silicates, denser, darker in color, and common in the oceanic crust. e.g Olivine

Question 2

What are the physical properties of minerals that are used to identify them?

Answer 2

-Hardness, the resistance to being scratched
-Colour streak, Streak refers to the observable color when rubbed across a hard surface.
-Lustre, the shininess/non-shininess of minerals.
-Cleavage, is when minerals break along a flat surface or into sheets
-fracture, when a mineral breaks with lots of jagged edges.
-specific gravity, the minerals density compared to water density
-specific properties, Some minerals have other specific properties that can be used for identification, such as: others will fluoresce
Different colors under UV light.

Question 3

How are igneous rocks formed and categorised?

Answer 3

-Categorized by their crystal texture and chemical compositions
- Formed through cooling of molten activity (lava or magma)

Question 4

How are sedimentary rocks formed and categorised?

Answer 4

-Sedimentary rocks form in layers called strata They are formed from weathering of particles when they are compacted and cemented.
- classified into different subgroups:
–Clastic sedimentary rocks are formed from weathering and eroded pieces of other rock, they are classified by size
–Chemical sedimentary rocks are formed by chemical precipitation
–Organic sedimentary rocks are composed of materials found by biological processes e.g. dead organic/ once-living materials.

Question 5

How are metamorphic rocks formed and categorised?

Answer 5

-Formed by heat and or pressure so they have a totally new form.
-The texture of metamorphic rock can be either foliated and appear layered or banded, or non-foliated and appear uniform in texture without banding.

Question 6

What is the rock cycle?

Answer 6

The rock cycle states that any rock type can be changed into any of the other two rock types and back again through the Rock Cycle

Question 7

What are the soil horizons?

Answer 7

O horizon → “organic” loose and partly decayed organic matter
A horizon→ is the most important layer for life, it consists of lots of
human and intense biological activities hence why it is darker in
colour
E horizon→ is located in between A and B and is ‘eluved’ zone of
leaching and is very pale because lack of nutrients
B horizon→ called subsoil and has less organic activity and contains
the most leached materials
C horizon→ known as subtraction which consists of weathered rock
and little organic activity
R horizon→ is bedrock and tend to be the base material for above
layers

Question 8

what is the law of superposition

Answer 8

In an undisturbed sequence of rocks, oldest rocks are on the
bottom. Youngest are on the top

Question 9

What are the Aboriginal quarrying and mining methods?

Answer 9

-Relied on stone tools to assist with hunting, gathering and processing of food and medicines.
- Stone tools were created at ‘quarry sites’ (open pit mines where particular stones of value were available)

Question 10

What are the methods of mining?

Answer 10

-Open pit mining, Excavation made on the ground surface.
-Underground mining, is used to extract ore from below the surface of the earth safely, methods include Room and pillar method, sub-level stop, cut, and fill.
-Onshore and offshore drilling, onshore drilling involves drilling a rig deep into the earth to reach fossil fuels while an offshore drilling rig drills underneath the seabed.