Rocks

Types of rocks

• $Igneous$
• $Sedimentary$
• $Metamorphic$

Igneous Rocks

Example: $basalt$ and $granite$

Formed as a result of $volcanic activity$ when molten $magma$ escapes from the mantle and $cools and hardens$. If it reaches the surface as lava it $cools and solidifies$ quickly whereas $magma$ inside the $crust cools slowly$

Basalt

• $Fine - medium grained$
• Black - Dark grey
• Formed when $lava cooled quickly on the Earth’s surface$ => $small crystals$
• Basalt is used for $road chippings$

  \

• Example: $Giant’s Causeway$, Antrim-Derry plateau

Granite

• Coarse grained
• $White, Grey, Pink or Black$

  \

• Formed when magma cools $slowly deep inside the earth’s crust$ => $Large crystals$
• Contains minerals of $feldspar$, $quarts$ and $mica$
• Granite is used for $counter tops$, $monuments$, $headstones$ and $fireplaces$

• Example: $Wicklow moutains$ and the $Mourne moutains in County Down$

  ##

  ## Sedimentary Rocks

Sedimentary Rocks

Example: $Sandstone$ and $limestone$

Formed from $particles$ of $dead plants$ and $animals$. $Sediments$ are $deposited$ on the $sea$ and $lake$ beds and on land. Layers of this material $builds up$ and is $compressed and cemented$ together creating solid rock.

Limestone

• Grey
• Coarse grained
• Formed over $millions of years$
• Made from the $particles of shells$ and the $skeletons of small creatures$. When $sediments sink$ to the bottom of the seabed, layers are built over time. The $weight of the upper layers$ compresses and cements the lower layers of sediments into strata (layers) to form solid rock

• Limestone is used for monuments and in construction of buildings
• Ground down => lime => spread on soil to increase fertility

Example: The Burren in County Clare

Sandstone

• Red/brown
• Coarse grained
• Formed from $sand$ that has been $worn away$ from the earth’s surface. This sand is carried away by $wind$ and $rivers$ and $deported as sediment$ in $seas$, $lakes$ and $deserts.$ The layers that are built up over time are $compressed and cemented$ together forming solid rock.

  \

• $Cork$ and $Kerry$
• Sandstone is used for $patios$ and as $building material$

\

Metamorphic Rocks

Example: $Quartzite$ and $Marble$

Formed from rocks that already exist such as $igneous$ or $sedimentary$ rocks. These rocks are changed into harder rocks due to great heat and/or pressure.

Marble

• $Li$^^M^^$estone$ => ^^M^^$arble$
• $Hard$ and $smooth$

  \

• White => Antrim
• Red => Cork
• Green => Conemara

  \

• Black => Kilkenny
• Formed when limestone is put under $great heat$ and $pressure$ due to $plate movement$ or when limestone comes in contact with $molten magma$
• Marble is used in $sculptures$, $monuments$, $kitchen worktops$, $floortiles$ , $fireplaces$ and $headstones$

Quartzite

• $Sandstone$ => $Quartzite$
• $Grey/white$
• Formed when sandstone is put under $great heat$ and $pressure$ due to $plate movement$ or when sandstone comes in contact with $molten magma$

  \

• $Extremely hard$ and $grainy$
• Found on $mountain tops$ => $not easily broken down$
• Used in $glass making$ and in $road surfaces$
• Example: $Croagh Patrick$ in Mayo

  # Uses of rock

  Natural resource: something in the natural world that people can use to their advantage

• Rocks are Natural resources   * Sources of energy and building materials

  ## Energy

• Some rocks can be used to create energy => fossil fuels

  ### Coal

• If close to the surface => mined in open pits
• If underground => mined in a mine
• Extracting from within the earth’s core => shaft mining

  ### Oil and gas

• Extracted from rock by drilling and pumping
• Can be done offshore in a rig

  \   ## Building materials   * Usually extracted by quarry   * Limes stone, sandstone + marble

  ## Impacts of quarrying and mining

  ### }}Positive impacts}}

  \

• Employment => supports local economy
• Supports other economic activities => provides material
• Provides raw materials to make:   * Glass   * Copper   * Steel   * Iron

  ### [[Negative impacts[[

  \

• Pollution
• Eyesore
• Traffic congestion

  \

\