Professor Cam Nelson
Scientifically, you know, limestone is important because it contains many fossils, and those fossils can be used to date the rock so that the geological period of time in which the limestone’s formed can be determined. The same fossils can tell us a lot about the environment in which the limestone formed.
There’s an economic importance hugely tied to limestones. Limestones, being built up largely of calcium carbonate, calcium carbonate has so many uses – let’s just touch on a few of these. New Zealand agriculture, farming, so very important, but many of our soils are a little acid and you have to decrease that acidity. The addition of lime to pastures has been absolutely fundamental in New Zealand’s sort of agricultural position. And of course that comes from the crushing of high-grade limestone to very fine sizes and the spreading of that onto pastures.
We all know how important concrete is in this day and age, and concrete to harden needs cement, and cement is made by mixing limestone with clay minerals. So the manufacture of concrete through cement is important.
We can move into petroleum. The world’s largest petroleum and gas fields are contained in limestones, and this is because limestones can have lots of holes in them, and any gas and petroleum that’s arising from deep down can end up being caught up in these holes. So the Middle East, for example, most of the hydrocarbons, the petroleum that is there, you are drilling into limestones to capture those hydrocarbons. And the same is true for some New Zealand limestones – they are known to contain petroleum.
There’s also the tourism aspect, caves, of holidays on a coral atoll, coral reef, of abseiling in countries with big steep cliffs which limestones often form. So there’s a huge tourist industry which is based effectively on limestones.
And then we could name other industrial applications that limestone gets into, you know, things that range from steel making to toothpaste to glass making – it goes on and on and on.
McDonald’s Lime Limited
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Lloyd Homer, GNS Science
Waitomo Caves Discovery Centre