Buoy I EARTH: Shingle and chalk rock.
Chalk and flintstone cliffs have been formed over millions of years. Chalk is made from tiny marine plankton skeletons and flintstone from compacted quartz crystals. Chalk is a soft material and flint very hard. Here on the Seven Sisters cliffs, chalk and flintstones have been laid down and compacted in layers. Over time, because the chalk is soft, water can seep in and wind erodes it causing major cliff falls every year. Wave action breaks down the fallen chalk blocks and grinds down the flintstones to pebbles and eventually sand. The seashore has no soil which is why most plants can’t grow on it. Soil starts to be formed when the pioneer plants and lichens die and decay. This forms humus, attracting soil creatures like worms, insects, soil bacteria and fungi. Fossil fuels: Over millions of years, decayed plants and animals have formed fossil fuels: huge underground reserves of coal, natural gas and oil. In just the last 200 years, we humans have upset the balance, by using vast quantities of these reserves to power our industries, our transport and homes.
