When most people think about fossils they usually think of things like great big dinosaur bones or possibly little seashells, or if you are really brave and think about fossil plants at all you probably think about a grey, brown rock with a fern squashed on it.
Well today I’m going to show you some fossils that don’t look like fossils. These brown leaves that you see here are all fossils. They are fossils leaves from the Eocene Period, which was about 40 million years ago and they come from Alcoa’s open-cut coal mine, these are in the overburden of that coal mine, which is located in Anglesea along the Great Ocean Road.
Once we got about a 1000 of them we were able to look at the size and the shape and compare them to some other plants we found in Australia and we realised that what we had here was a fossil rainforest. This was emphasised by the fact that maybe of the first 500 leaves we looked at there were over 100 different kinds. So we got to the point that we knew we had a fossil rainforest, a tropical rainforest. Wait a minute, Victoria isn’t tropical but this says it was tropical. How can that be possible?
The Eocene was a very important time in Victoria. Australia was still connected to Antarctica and to South America to a continent called Gondwana. And this is particularly important because Victoria was the hinge, the last connection between Antarctica and Australia and when that severed, cold ocean currents circulated, the climate deteriorated rapidly.
No more could tropical rainforest plants be happy in Victoria and any organism faced with a major environmental change has three choices: number one, it can stay there and become extinct, number two it can evolve to the new set of parameters or number three, it can run away and it does that by selectively breeding in one direction so the whole population moves though millions of years.
We have examples of all of those here. One of the reasons I started to be a palaeobotanist and I’m still a palaeobotanist is that every time I split open a rock and see something inside it’s like opening a Christmas present and I realise that I am the first eyes to see that in 40 million years and that buzz keeps me going.