Earth Materials

Question 1

What are the characteristics of Mafic Magma?

Answer 1

Dark coloured. Has lower silica contents and are rich in Iron and Magnesium

Question 2

Define the three types of Chemical Bonds

Answer 2

Classical Bond: Sharing electrons (often nonmetals)
Ionic Bond: Ions electrically hold together (Metal and nonmetal)
Metallic Bond: Between metal and metal, compounds that are two or more atom mixtures have easily separateable compounds

Question 3

What are Clastic Rocks?

Explain their location in streams

Answer 3

Formed from fragments of other rocks. Fragments carried by moving water. Particles and sorted by size (Largest to smallest)
Sands and gravels compact and cement to form conglomerate (Coarsest material)
Sands compact and cement together to form sandstone (Porous and Water permeable)
Silts and clay compact and cement to from shale
(Smooth, soft easily broken and water impermeable)

Question 4

What is a cleavage?

Answer 4

Tendency of a mineral to split along a plane. Spilting occurs where weakest bonds are

Question 5

How does Coal form and what are it’s types?

Answer 5

Organic sedimentary formed from ferns, mosses and parts of trees.
Swamp matter decays and compacts into PEAT
Sedimentation and compaction of PEAT which relases gas and water from it and forms LIGNITE
Million years later it submerges, becomes harder and forms BITUMINOUS COAL
ANTHRACITE, metamorphic coal takes longest and greatest exposure to pressure and heat. Gives greatest source of energy

Question 6

What are the types of Sedimentary rocks?

Answer 6

There are three types:
Chemical Rocks: Chemical sediments form as minerals precipitate or fall out of solution
Clastic Rocks: Formed from fragments of other rocks
Organic Rocks: Formed from the remains of plants and animals

Question 7

What are the features of Sedimentary Rocks?

Answer 7

Stratification: The layering of sedimentary rock
Bedding Plane: Line between layers (Usually horizontal but can be angled)
Fossil: Remains or evidence of an organism preserved
Ripple Marks: Caused by winds, streams or waves
Geodes: Spheres of silica rock that contain crystal inside them

Question 8

What are Fractures?

Answer 8

A break that is not along a cleavage surface. Can be rough, smooth or splintery.

Question 9

What is an Igneous Rock?

Answer 9

Rocks that are formed from the crystallization of magma.

Question 10

What are the two types of Igneous Rock?

Answer 10

Extrusive: Fine grained igneous rocks that cool quickly on Earth’s surface
Intrusive: Coarse grained igneous rocks that cool slowly beneath Earth’s surface

Question 11

What are the three main groups of Igneous Rocks?

Give examples.

Answer 11

Felsic: Light-Coloured and have high silica (Granite, Rhyolite, Pumice)
Mafic: Dark-coloured, have lower silica contents and are rich in Iron and Magnesium (Gabbro, Basalt, Breccia)
Intermediate: Characteristics of both Felsic and Mafic rocks (Diorite)

Question 12

List and explain the members of the Granite family

Answer 12

Formed from cooling of felsic magmas
Granite: Intrusive (Uplift and erosion)
Pumice: Formed in silica-rich lava that had gases bubble out. Resembles sponge
Obsidian: Glassy texture with a hardness of approx 5. Brittle
Rhyolite: Felsic, light coloured rock. Fine grained

Question 13

Types of Metamorphism:

Local

Answer 13

Occurs only in relatively small areas of Earth’s crust. 2 types:
Contact: Hot magma enters heated and reacts with it’s mineral to produce new rock (Shale to Hornfels)
Deformational: Occurs at faults of relatively low temperature at high pressure, stress and friction which cause rock to deform and change structure and texture.

Question 14

Types of Metamorphism:

Regional

Answer 14

Occurs in a large area of the Earth’s crust
Can occur during crust mountain building movements. Buried rocks have greater weight, pressure is greater in one direction and rocks align in layers.
Fewer changes occur if parent rock is dry. Factors may occur in many combinations.

Question 15

What are Minerals and what are their characteristics?

Answer 15

An inorganic solid with crystalline structure, unique chemical composition and naturally made. More than 90% in Earth's crust contain O and Si
5 most common characteristics:
Solid
Atoms have an orderly pattern
Inorganic
Naturally made
Specific organic compostion

Question 16

Explain the magma process

Answer 16

Magma containing freely moving particles rise up. Molecules and atoms move closer and bond as magma cools. Mineral compounds formed and mass together over time.

Question 17

Explain the Pressure process

Answer 17

Minerals within rocks start to break down chemically due to high temperature and pressure
Extremely high temperature and pressure cause mineral to change but stay solid
Molecules, atoms and ions bond producing minerals.

Question 18

What are Plutons and explain the different types

Answer is very long

Answer 18

Rock masses of cooled magma. Types:
Lacolith: Dome-shaped mass of intruded igneous rock
Volcanic Neck: Solidified lava filling central vent of extinct volcano
Stock: Large igneous intrusion with exposed S.A of less than 100 kmsquared
Dike: Igneous intrusion that cuts across rock layers and formed when magma intrudes into vertical bedrock
Sill: Sheet of intrusive igneous rock formed between rock layers parallel to the rock layer it intrudes
Batholith: Largest pluton, igneous rock exposed by erosion, forms core of many mountain ranges

Question 19

What are the types of Carbon and their atomic arrangement?

Answer 19

Occurs as diamonds or graphite
Diamond very strong, graphite very brittle
Diamond forms tetrahedron bonds as an interconnecting network
Graphite forms silica ringed sheets with weak london forces

Question 20

What are rock-forming minerals?

Answer 20

Minerals known to form rocks

Ex: Olivine, Quartz, Feldspar, Mica, Pyroxene and Amphibole

Question 21

What are silicates?

Answer 21

Minerals that have O and Si triangular prism (Silica terahedron) as the building blocks
Most common minerals, 95% of the Earth’s crust and 97% of Earth’s mantle
Ex: Feldspars and Quartzs

Question 22

What is a streak?

Answer 22

Colour of a minerals powder. Usually consistent with mineral.

Question 23

What is fossil fuel obtained from Shale?

Answer 23

Petroleum and oil

Question 24

Explain the rock cycle

Answer 24

Refer to diagram in book for better explanation
SEDIMENTS undergo deposition, burial and compaction, cementation to form SEDIMENTARY ROCK which undergoes heat and pressure and becomes METAMORPHIC ROCK. Which eventually melts to become MAGMA and then solidifies to form IGNEOUS ROCK. Which is then uplifted, weathered and eroded to become SEDIMENTS.