Module 2 - Geology

Question 1

Explain, by use of a diagram how the earth is structured in relation to Core, Mantle and Crust.

Answer 1

Those four major layers are various
proportions of chemical elements

such as iron, nickel, oxygen and aluminium.

Question 2

How are these rocks formed? (Igneous, Sedimentary and Metamorphic Rock)

Answer 2

Igneous rock are formed when magma rises up and cools down. Classified into extrusive (lava that cooled on surface) or intrusive (solidifies beneath the upper surface).

Sedimentary rock composed of geological materials, formed when particles of minerals are compacted under massive pressure (two types: 1.composed of organic matter, 2. composed of inorganic matter due to mainly mechanical weathering)

Metamorphic rock are formed through heat and pressure. Beyond a stable range (a higher temperature and/or pressure) minerals will break down or combine with neighbouring minerals to develop new minerals.

Question 3

What is the difference between Magma & Lava?

Answer 3

Magma is a molten (semi-liquid) mass of elements, and even rock pieces that is formed in the mantle of the earth. It either solidifies beneath the surface (intrusive igneous rock) or can erupt on the surface of the Earth as lava (extrusive igneous rock).

Question 4

What are three characteristics of granite?

Answer 4

Large crystals;

Weather resistent;

Forms sandy soils (acidic & nutrient poor)

Question 5

Why is Geology important for Guides?

Answer 5

Structure of rocks determine the type of soil. This determines the type and growth of plants, thus the herbivores that occur there and therefore also the predators in the area.

Question 6

Two main factors that shape the earth

Answer 6

1. Gravity (pressure)
2. Heat (temperature)

Question 7

What is topography?

Answer 7

Study of the land and the weather features of an area

Question 8

What are minerals?

Answer 8

Naturally occuring crystaline substances

Question 9

Properties of granite

Answer 9

1. Rock outcrops weater resistant
2. Acidic, nutrient poor soils
3. Coarse-grained, sandy and pale colour
4. Larg-leaved trees on crest (buswillow/Marula)

Question 10

Properties of basalt

Answer 10

1. Alkaline, nutrient rich soils
2. Sark colored soils
3. Easily weathered outcrops
4. fine-grained and clayey
5. Small leaved trees (Acacias)

Question 11

What is a Geology?

Answer 11

Geology is the study of the composition, structure andhistory of the earth. Earth is made of rock, composed of minerals. Gravityand heatshaped the Earth

Question 12

What types of weathering are there?

Answer 12

1.

Mechanical (physical) Weathering :Examples: exfoliation, frost wedging, salt wedging, temperature changes and abrasion

Chemical Weathering: Examples: carbonation, hydration, hydrolysis, oxidation and solution.

Biological Weathering: Examples: organic activity from lichen and algae, rock disintegration by plant or root growth, burrowing and tunnelling organisms and acid secretio