Rocks (ch.7) Flashcards
(24 cards)
How are igneous rocks formed?
Formed when magma cooled down and solidified either on the surface or within the crust.
Granite
Formation: Magma cools in the earth’s crust; intrusive rock
Crystals: 1. Large 2. Mica, feldspar and quartz
Texture: Rough
Colour: Grey, speckled
Hardness: Hard
Location: Wicklow Mountains
Basalt
Formation: Magma cools on the Earth's crust; extrusive Crystals: 1. Very small 2. Iron oxide Texture: Smooth Colour: black, dark grey Hardness: Very hard Location: Giant's Causeway, Co. Antrim
How are sedimentary rocks formed?
When small particles or sediments are deposited on the bed of seas and lakes and compressed together to form layers or solid rock.
Limestone
Formation: Sediments and dead sea creatures settled at the bottom of seas and lakes and were compressed to form layers of rock. Texture: Smooth to rough Colour: Pure white to grey Hardness: Soft, easily scratched Location: The Burren, Co. Clare
Sandstone
Formatio: Layers of sand compressed and cemented together by silica on the ocean floor. Texture: Smooth to rough Colour: Yellow to red Hardness: Harder than limestone Location: Co. Cork and Co. Kerry
How are metamorphic rocks formed
Older rocks are changed into new types of rocks as a result of great heat or pressure. i.e. shale becomes slate
Marble
Formation: Great heat from magma baked limestone and formed crystals
Texture: smooth, cold to touch
Colour: White to black with veins of red, green, yellow and white
Hardness: Hard
Location: Green marble (extracted for its minerals) is found in Connemara
Quartzite
Formation: great heat from magma baked and hardened sandstone
Texture: smooth to rough
Colour: white to grey, sparkly
Hardness: very hard
Location: Great Sugarloaf Mountain, Co. Wicklow
Uses of granite
worktops and fireplaces
Uses of limestone
monuments
construction of buildings.
cement
improve soil fertility
Uses of quartzite
used in road chippings, sandpaper and watches
Uses of marble
fireplaces, gravestones and ornaments
Natural resources
materials occurring in nature which can be exploited for economic gain
Extraction
The removal of natural resources from the earth’s surface
Exploitation
The use of natural resources for economic purposes
Primary Economic Activities
- industries involved in the extraction and production of raw materials.
1. Fishing and aquaculture
2. Agriculture
3. Forestry
4. Mining
Farmers, Foresters, Miners
Secondary Economic Activities
- turning the outputs of primary activities (raw materials) into finished goods
1. Industry
Workers in a flour mill, Bakers, Manufacturers of computers
Tertiary Economic Activities
- industry involved in providing services
1. Professional services
2. Information Technology
3. Selling (retailing)
Shop assistants, Doctors, Hairdressers
Extraction of rocks = drilling
oil and gas are extracted from underground reservoirs by drilling down into the ground and pumping it to the surface. If oil or gas is found under the sea, drilling takes place from an offshore platform or rig. The oil or gas is then pumped ashore through a pipeline. This is called offshore drilling.
e.g. Kinsale oil and gas
Extraction of rocks = opencast mining/quarrying
If a resource is on or near the surface of the Earth, opencast mining is used to extract it. This is the cheapest form of mining, but it is very noisy and dusty and can scar the landscape.
Used to extract stone, gravel and sand for use in the construction industry.
Extraction of rocks = Shaft mining
Used if a resource is lying within seams deep in the Earth. Vertical shafts are constructed to reach the seams and bring it to the surface. This form of mining is very expensive and dangerous and can spoil the landscape. Shaft mining is used to extract coal and metal ores.
e.g. zinc and lead ores are extracted from the Tara Mines in Navan, Co. Meath.
Describe the environmental, economic and social consequences of the Tara Mines
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Describe the environmental, economic and social consequences of Deepwater Horizon
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