巖石圈——石灰?guī)r英文版.ppt

1、HIGHER GEOGRAPHY LITHOSPHERELIMESTONE SCENERY,There are several types of limestone in Britain - this presentation will concentrate on Carboniferous Limestone and look at the Yorkshire Dales in particular.,These limestones were formed from the fossilised remains of countless marine plants and animals

2、, such as corals, which lived during the Carboniferous period, 345 - 280 million years ago.,These former sea beds were moved from the equator due to continental drift and forced upwards during the Hercynian orogeny or mountain building period, 280 - 230 million years ago.,Britain during the Carbonif

3、erous. Here, on the Great Barrier Reef off the Australian coast, is the worlds biggest expanse of coral reef.,Brain coral, one of the main reef building species.,The Dolomite mountains in the Alps - these 3000 metre peaks are made of limestone and were once the bed of the sea!,Limestone - Chemical w

4、eathering,Limestone = Calcium Carbonate Rainwater = Carbonic Acid Carbonic Acid dissolves Calcium Carbonate This is called CARBONATION, a type of solution weathering. Or H2O + CO2= H2CO3 CaCO3 + H2CO3 = Ca(HCO3)2 Calcium Carbonate Dilute Carbonic Acid Calcium Hydrogen Carbonate (Soluble),Carbonation / solution weathering also attacks buildings made from limestone,This type of landscape is more correctly known as Glacio Karst - glacio because it has also been glaciated, and karst after an area in Slovenia, which gives its name to this kind of landscape.,The dry, barren landsca