Rocks Flashcards
How rocks differ
Mineral content
Colour
Hardness
Texture
Groups rocks are divided into
Igneous (ingite, fire, eg. magma, lava)
Sedimentary (means pieces)
Metamorphic (means change)
Igneous rocks
Comes from latin word meaning fire
Formed as result of volcanic activity
Hot molten magma cooled, solidified on surface/within crust
Granite + Basalt
Sedimentary rocks
Remains (sediments) of other rocks, animals, plants
Deposited on beds of seas, lakes, on land
Compressed over time, cemented together
Limestone, sandstone, shale
Metamorphic rocks
Metamorphic - to change
Rocks changed in shape/form by great heat + pressure
Already existed as igneous/sedimentary rocks
Marble, quartzite, slate
Granite
Formed - molten magna cools under earth’s surface
Cooled slowly - millions of years, large crystals
Eventually comes to surface when overlying rocks worn away
Varies in colour - black/grey/pink
Used in building industry & for monuments
Mourne Mountains & Wicklow Mountains
Basalt
Lava cools on earths surface
Cooled v quickly, tiny crystals
Dark grey to black
Antrim - Derry plateau. Giant’s causeway
Limestone
Remains of ting sea creeatures, fish, shells
White to grey
Permeable (allows water to pass through it)
Burren co. Clare & Central plain of Ireland
Make monuments/soil fertility
Sandstone
Sand deposited on beds of lakes & rivers & deserts
Brown to red
Building materials
Mountains of Munster
Marble
Limestone put under great heat & pressure –> marble
Pure marble - white. Other minerals present - vary red, green, black
Hard rock, used for fireplaces, gravestones, ornaments
Connemara & Cork
Quartzite
Sandstone came into contact with magma deep in earth’s crust
Consists mainly of grains of quartz tightly packed together
Grey to whitr
Extremely hard rock, Mayo, Donegal, & Wicklow
Rocks
Hard material that forms Earth’s crust
