Well I’m sitting on a big rock on the shoreline of former Lake Eppalock, which is about 100km north of Melbourne in Central Victoria. If we go back say 300 million years then the climate here would have been completely different.
It’s the start of the Permian Period and most of Victoria including this part here was covered with an ice sheet. It was an ice sheet that wasn’t exactly like the Antarctic ones, it had some water associated with it, every now and again it melted a bit so there was some water flowing under the ice sheet and there was some lakes and small streams associated with it.
We know all this because the rock I’m sitting on, if you have a look, you can see that it’s a broad smooth rock that’s got scratches or striations along it and these are all in the same direction pretty much. The scratches were made by pebbles caught up in the ice, at the bottom of the ice sheet or the small glacier that we think was actually here and as they move they gouged these long grooves out. Well as well the evidence from the pavement here with the grooves, there are also some other important lines of evidence and that is the foreign rocks or pebbles that are found in this area that are completely foreign to this part of Victoria, in fact to any part of Victoria.
We can recognise a big range in different textures and colours, we know they’ve probably been brought in from a long way away – Antarctica is the most likely. But these rock types tell us a lot about the history of this area and allow us to make a pretty definite conclusion that that’s what was going on here that long time ago.
Well the importance of sites like this, which show that there were periods in the past where massive ice sheets covered the continent or parts of Victoria, is that climates change over time, continents move around and the important thing is to be able to recognise that in the geological record. So being able to come to an outcrop or an occurrence like this and to be able to interpret it is a really sort of rewarding experience because it enables you to use modern day occurrences to look back deep into the past.