Tuesday, 24 July 2007

The You Yangs

News flash! The You Yangs are disappearing.
Well, it will take a while, but wind and rain have been eroding the You Yangs for millions of years and are still doing so today. The resulting sand is deposited in pockets at the base of the rock. In fact there is so much of it that it has been mined to help build the Melbourne-Geelong stretch of the Princes Highway.

You Yangs

The You Yangs are a landmark in the district. They stand about 350 metres above the plain but it wasn't always like that.
Some people think that the hills are an extinct volcano but not so. This is what actually happened. When this whole area was under the sea, magma pushed its way upwards towards the surface but didn't break through. It started to cool very, very slowly until it was a rock called granite. (Geologists can look at granite under a microscope and see the large crystals of quartz and feldspar that form when the magma cools slowly. If it had been on or near the surface, and cooled quickly, the crystals would be much smaller.)
Then came a long period of time when the earth was much cooler, and as the ice caps grew the sea level dropped. Sediments on the exposed land eroded away leaving the granite that we now call the You Yangs exposed as a rocky island, surrounded by a shallow sea. Sea levels continued to fall, and then the surrounding area was subjected to a great deal of volcanic activity.
All of this took about 400 million years, an impossible length of time to try to imagine. Here endeth the lesson.
It's worth visiting the You Yangs to check out the flora and fauna. Local naturalists get excited by what they find there from time to time. And it's worth climbing Flinders Peak (in 1802 Matthew Flinders was the first European to climb the You Yangs) - the views are fantastic. You'd better plan a visit before it disappears!

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