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Rocks chapter 2
About formation of rocks
Term | Definition |
---|---|
Sedimentary | Rocks formed when the skeletons of sea creatures and sand are compressed and cemented together |
Metamorphic | Rocks which were once different rocks and were then changed due to great heat and pressure |
Igneous | Rocks formed when lava spreads across the earths surface and cooled very quickly or when magma cools very slowly in the earths crust |
Limestone | Sedimentary rock which was formed when tiny sea creature skeletons where compressed together. It is permeable. Exposed limestone can be found in the burren in co. Clare |
Quartzite | Metamorphic rock formed when sandstone was put under great heat and pressure. It can be found on mt. Errigal in co. Donegal |
Marble | Metamorphic rock formed when magma forces it's way into the body of limestone and puts it under great pressure. It's no longer permeable. Found in Connemara |
Sandstone | Sedimentary rock formed when large amounts of sand are transported by the wind and rivers and are then deposited on sallow sea beds and are the put under great pressure and are compressed and cemented together |
Basalt | Igneous rock formed when lava spreads out on the earths surface and cools very quickly. It has tiny microscopic crystals. It is found in the giants causeway |
Granite | Igneous rock formed when magma cools very slowly in the earths crust. It has large crystals. |
Off shore drilling | Technique used to extract oil and gas off shore |
Open cast mining | Digging a hole in the ground to get minerals that are close to the surface |
Shaft mining | Going down a shaft to get minerals that are deep in the earths crust |