Theory question 104
Rocks and Soil Formation(a) Explain briefly the processes of formation of (i) igneous rock; (ii) sedimentary rock; (iii) metamorphic rock.
(b) Give two examples of each of igneous and metamorphic rock and three examples of sedimentary rock.
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(a)(i) Igneous: molten magma from inside the earth cools and solidifies, either underground (intrusive) or on the surface as lava (extrusive)
(ii) Sedimentary: fragments of weathered rock and remains of organisms are carried by water/wind, deposited in layers and compacted and cemented over long periods
(iii) Metamorphic: existing igneous or sedimentary rocks are changed in form and structure by great heat and pressure
(b) Igneous: granite, basalt, gabbro, dolerite. Metamorphic: marble, slate, gneiss, quartzite, schist. Sedimentary: sandstone, shale, limestone, clay, coal, conglomerate
Explain each formation, then give examples.