How can fossils help us find out what the geography of the world was like then?
Fossils can be used to determine past geography and climates, by comparing them with modernday relatives. For example, is coral fossils have been found, we can look at todays fossils and see that the climate in that area at that time (through carbon/radioactive dating) was. For instance todays corals are found in 27oC water, low sailinity, shallow waters (50m) in the photic zone and within 30degrees either side of the equator. This is known as the Principle of Uniformitarianism – The present is the key to the past. Facies fossils can also be used as they are only found in certain lithologies. Fossils/Fish/Shell fossils obviously indicate that at that point in time when they died, and fell to be deposited and preserved, there was an ocean there. For example, ammonites found in shales. The shale also indicates deep seep conditions. Very dark, black fossils have been carbonised due to anoxic conditions, low in oxygen where the organic parts have turned to carbon. This would indicate deep
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