Rocks

Question 1

What are minerals?

Answer 1

Naturally occurring inorganic substances which have a repeated atomic pattern and a definite chemical composition

Question 2

Who are mineralogists?

Answer 2

Scientists who study minerals

Question 3

How many mineral groups are there and what are they?

Answer 3

There are 8 mineral groups and they are:-

1. Silicate minerals
2. Native elements
3. Halides
4. Oxides
5. Carbonates
6. Phosphates
7. Sulfides
8. Sulfate

Question 4

MINERAL IDENTIFICATION

Colour

Answer 4

Mineral is rarely identified by Colour. Many minerals have the same colour. EX: pyrite is gold colour but contains no gold atoms and is commonly referred to as’ fools gold’. Many minerals are also coloured by chemical impurities. Other factors can be weathering,

Question 5

MINERAL IDENTIFICATION

Streak

Answer 5

Streak is the Coloured power of the mineral. To do a streak test you have to rub a mineral against a porcelain plate. Many minerals can be told apart by this.

Question 6

MINERAL IDENTIFICATION

Luster

Answer 6

Luster is the way light reflects on the mineral. There are two ways in which geologists categorize luster, metallic and non-metallic.

Question 7

MINERAL IDENTIFICATION

Hardness

Answer 7

Shows how hard a mineral is. You need a sheet which is usually harder than the mineral and slide it across the sheet. The Mohs hardness scale is a scale in which the hardness of each mineral is shown.

Question 8

MINERAL IDENTIFICATION

Cleavage and fracture

Answer 8

Cleavage
The way crystals of a mineral break along certain planes. Mineral with different cleavage structures break in different ways. They each form a different shape. EX: Halide forms a cube and fluorite forms an octagon.

Fracture
How a mineral breaks without a pattern. You can identify minerals with this. If it splinters like wood it is fibrous.

Question 9

Igneous Rocks

Answer 9

Igneous rocks are formed by the cooling of magma. Magma sometimes cools deep within the crust or closer to the crust. Igneous rock can be split into two types, Intrusive and extrusive igneous rocks. We can identify these both by the crystal formation.

Question 10

IGNEOUS ROCKS

Intrusive Igneous rocks

Answer 10

Intrusive igneous rocks form deep within the crust. They cool slowly which lets the crystals grow a bit. They are also called plutonic. Pluton is a sheet of igneous rock that forms within the crust. After a while once the igneous rock is fully cooled they come up to the surface because they are less dense.

Question 11

IGNEOUS ROCKS

Extrusive Igneous rocks

Answer 11

Extrusive igneous rocks cool above the surface. They cool fast and the crystals don’t have time to grow. Sometimes they cool so fast that the crystals don’t form, and they have a glass like structure. A good example of this would be obsidian. Others have air bubbles trapped inside them
. Pumice has air bubbles trapped inside it and that is why it is light and floats. Extrusive igneous rocks are called Volcanic.

Question 12

Sedimentary rocks

Answer 12

There are 3 types of sedimentary rocks. Clastic chemical and organic

Question 13

SEDIMENTARY ROCKS

Clastic sedimentary rocks

Answer 13

Clastic sedimentary rocks are cemented together. Breccia has big sediments and sandstone has sand sized sediments. In calm water in the ocean floor. One layer always deposits on top of another. So each layer is younger than the layer beneath it. When the sediment hardens the layers are preserved. Sometimes in these layers there are fossils found.

Question 14

SEDIMENTARY ROCKS

Chemical sedimentary rocks

Answer 14

Formed by crystallization of chemical precipitates. When ions are deposited in water they are left out which are then formed to become chemical sedimentary rocks with the help of organisms.

Question 15

SEDIMENTARY ROCKS

Organic sedimentary rocks

Answer 15

Are formed by decomposed living organisms that are cemented with other sediment. Plant bodies decompose and become coal. Shells cemented together make limestone. Limestone can be considered organic or chemical sedimentary rock.

Question 16

What is a metamorphic rock?

Answer 16

Metamorphic rocks start off as some kind of rock. The starting rock can be igneous, sedimentary, or even another metamorphic rock. Heat or pressure then change the rock into a metamorphic rock. The change can be physical, chemical, or both.

Question 17

METAMORPHIC ROCK

What is metamorphism? How does it occur, and what are the types of metamorphism?

Answer 17

During Metamorphism a rock can be physically or chemically altered. If it happens chemically ion pass through and are changed. This creates a new mineral. The new minerals that form during metamorphism are more stable in the new environment. If there is immense heat and pressure the rock may be changed physically as well. If there is pressure from only one side the rock forms layers. This is called foliation. If pressure is exerted from all directions the rock will not show foliation (non-foliated). The 2 main type of way a rock reaches metamorphism is regional and contact.

Question 18

METAMORPHIC ROCK

Contact Metamorphism

Answer 18

Contact metamorphism occurs when magma comes in touch with the rock. The rock changes dues to the magmas extreme heat.

Question 19

METAMORPHIC ROCK

Regional Metamorphism

Answer 19

Regional metamorphism occurs over a wide area. Great masses of rock are exposed to pressure from rock and sediment layers on top of it. The rock may also be compressed by other geological processes. If the rock is buried deeply, it may experience high temperatures. Some regional metamorphic rocks show foliation.

Question 20

SOIL

What is soil?

Answer 20

Soil is the layer that cover the top of the earth. It covers the whole top layer including ocean beds. Soil is a mixture of minerals, water, air and organic matter that formed from decomposed remains of plants and animals and waste produced by living things. It also contains living organisms.

Question 21

SOIL

Why is soil important?

Answer 21

Soil is important because:

1. Plants extract water and nutrients from soil and use soil to anchor themselves.
2. Organisms such as bacteria, fungi and animals live in soil.
3. Soil helps cycle nutrients and substances, such as carbon and nitrogen, in the environment.
4. Water precipitates to the ground and flows along Earth’s surface. Water seeps into the ground to form groundwater. Soil filters and cleans the water.

Question 22

SOIL

Parts of soil (non-living)

Answer 22

There are 5 major non-living components of soil:

Sediments: small particles of broken down rock.

Minerals: important elements needed by living things in the soil, make up rocks, determine the fertility of soil

Nutrients: substances in soil that are used by living things to survive; the most important nutrients are nitrogen, phosphorus and potassium

Water: Water is found in between the particles of soil

Organic Matter: made from dead and decaying organisms

Question 23

SOIL

Parts of soil (living)

Answer 23

Many living things live in soil or depend on soil:

Plants: establish their roots in soil to extract nutrients, water and other substances to help them grow

Bacteria: help decompose dead organisms, and they help “prepare” nutrients, such as nitrogen, in the soil. Bacteria are plentiful in soil - 1 teaspoon of soil can have up to 1 billion bacteria!

Animals: some animals, such as snakes and groundhogs burrow in soil, insects (ex. worms) in soil help decompose dead organisms

Fungi: important decomposers that break down dead organisms

Question 24

SOIL

What factors affect soil formation?

Answer 24

Soil can take a long time to form. In fact, soil can take up to 1,000 years to form! There are 5 factors that influence how fast soil forms:
Organisms
Topography
Climate
Parent Material
Time

Question 25

SOIL | What are the 3 soil textures?

Answer 25

``` These are the 3 soil textures Sand Large coarse partials that make it rough Clay Holds water and nutrients. Dry is hard and smooth wet is sticky Silt Medium size particles ```

Question 26

SOIL | What are the 3 main types of soil?

Answer 26

The 3 main types of soil are: Loamy soil Clay soil sandy soil

Question 27

SOIL | Sandy Soil

Answer 27

Sandy soil is not entirely made of sand. It cannot hold water and is not good for plants. It is most commonly found in beaches.

Question 28

SOIL | Clay soil

Answer 28

It is mostly made of clay. Clay has small particles that tend to stick together. This does not let water and nutrients enter. Due to this it is poor for plants.

Question 29

SOIL | Loamy soil

Answer 29

Loamy soil is made of almost equal parts sand, clay and silt. For this reason, it has characteristics of all three types of soil textures. It is considered the ideal soil type as it holds on to water & nutrients and drains water well.

Question 30

SOIL | Layers of soil

Answer 30

``` The layer of soil are called horizons. There are 5 major horizons of soil: O Horizon (Humus) A Horizon (Topsoil) B Horizon (Subsoil) C Horizon (Parent Material) R Horizon (Bedrock) ```

Question 31

SOIL | What is the O horizon

Answer 31

Mostly made of leaf litter and decomposed organic matter. We call the decomposed organic matter humus. For this reason, the O horizon is also called humus.

Question 32

SOIL | What is the A horizon

Answer 32

When we talk about soil types, we are often referring to the soil in this layer. This layer is made of mineral and rock particles mixed with humus. This is the primary layer where plants grow and animals live.

Question 33

SOIL | What is the E horizon

Answer 33

Sometimes a light coloured region of soil forms at the bottom of the A horizon. This is where minerals are “picked up” and carried to the subsoil. Some texts assign this light coloured region as a separate horizon called Horizon E.

Question 34

SOIL | What is the B horizon

Answer 34

This layer is mostly made of clay and mineral deposits. When water drains through the topsoil, it carries minerals with it. When the water moves through the subsoil, the minerals are left behind. This process is called leaching

Question 35

SOIL | What is the C horizon

Answer 35

This layer is made of slightly broken up or weathered rock. The rock in this layer is considered to be the parent material to soil. There is no organic matter in this layer.

Question 36

SOIL | What is the R horizon

Answer 36

This layer is called bedrock. Bedrock is solid rock. Over time, bedrock will weather or break down, forming the non-organic (inorganic) particles that make up soil.