Unit Earth Space Observatory Chapter 6 The Lithosphere

Unit: Earth & Space Observatory: Chapter 6 The Lithosphere & The Hydrosphere Pages 182 - 219

General Information • It is 6300 km from the Earth’s surface to its centre. • The hard shell is, on average, 100 km thick

Lithosphere • The lithosphere is the hard shell. • It consists of both the crust and the top part of the upper mantel. • It contains all the minerals and rocks.

Use diagram from 184 in TB

Minerals • Minerals are inorganic substances that cannot be made. (not from animals nor plants) • With over 4000 minerals, each have certain characteristics or properties defined by their composition. • Cubic shape → salt (Na. Cl) • Gold (Au), Silver (Ag), Tin (Sn), etc. • Quartz → silicone dioxide (Si. O 2)

Mineral Classification • Minerals can be classified according to: 1) Colour: – An ‘idiochromatic’ mineral is a specific colour since a certain element is present in its composition. (azurite, ruby, etc. ) - An ‘allochromatic’ mineral is colourless when they are chemically pure. (quartz, diamonds, etc. )

Example: Allochromatic Mineral Quartz

Mineral Classification 2) Transparency: - how much light is able to pass through (transparent, translucent, opaque) 3) Hardness: - depends on strength of bonds between atoms - Mohs scale measures resistance to scratching (0 is liquid, 1 is softest (talc) and 10 is hardest (diamond))

Mineral Classification 4) Streak: - after mineral is rubbed onto unglazed porcelain (idochromatic leaves brightly coloured powder) (allochromatic leaves white or pale powder)

Mining Process � 1) Locate the mineral. � 2) Extract from lithosphere as an ‘ore’. �Ore is a rock that contains the mineral. �Deposit refers to a large quantity a mineral available for mining. � 3) Mineral is separated from ore. �Each ore is processed differently. • Gold is crushed, treated with chemicals and is melted. (500 kg ore yields 6 g)

Type of Mines • 1) Open-pit mine – Deposit is found near the surface – Upper layers are removed by drilling machines, excavators, and dump trucks

Type of Mines • 2) Mine Drift – Deposit is too far below the surface – Vertical shafts with drifts that run alongside the vein of the deposit – Each drift needs air ducts and water supply lines

Rocks • Minerals can cluster together heterogeneously to form rocks. • There are two theories on the formation of rocks: – 1) Neptunism: by pressure of water – 2) Plutonism: by volcano

Rock Types • 1. Igneous Rocks – Formed from solidified magma, • extrusive (hardens on contact with air) or • intrusive (hardens before reaching surface) • 2. Sedimentary Rocks – Formed from eroded rock fragments combine with plant and animal remains under pressure

Rock Types • 3. Metamorphic Rocks – Formed from the transformation of igneous or sedimentary rocks into metamorphic rock under high temperature and pressure – Properties and appearance will change

What rock is it? metamorphic igneous sedimentary