MT GAMBIER: Matthew Flinders & the Coastal Landforms of SE Australia

'Mt Gambier Peaked ... Mt Schank Flat topped ... Cape Northumberland ... Sandy hillocks on the front bank' - from Matthew Flinders' chart
Flinders attributed the discovery of this coast to Captain Nicolas Baudin, 1802, just prior to their encounter. Baudin had sailed westwards along this coast, meeting Flinders at a bay that Flinders named Encounter Bay. After the encounter Flinders sailed eastwards along this coast. He did not stop to explore the land, as he knew that someone had preceded him, and the pressure of time to reach Sydney (and beyond) while weather conditions were still favourable, was beginning to mount.	Flinders' chart, Mt Gambier Extract from Flinders' chart
The city of Mt Gambier is dominated by the picturesque Blue Lake, a volcanic crater formed during Australia's most recent eruptions. Behind the lake is Mt Gambier, composed of ash and tuff. Nearby, are other volcanic lakes. Water from the surrounding region soaks into the crater, the floor of which lies below the water table. Some water seeping through rocks, and filling lakes of the area, originates in limestone to the north. The town's water supply is drawn from the lake; the pumping station is shown on the lake edge on the right of the photo. The signboard (right) summarises key points of the Blue Lake. Of particular interest is the mention of the lake's colour change. It should also be noted that Blue Lake is quite deep. Around the lake many informative signs can be found. The original surface (prior to volcanic activity) was limestone, formed in a sea from numerous animal shells and skeletons. This rock is still found beneath the surface volcanic pyroclastic rocks (ash and scoria) and lava. These pyroclastic rocks formed from exploded fragments, blasted outwards from the eruptive centre in a violent explosion.	Blue Lake Photo 1: Blue Lake and Mt Gambier centre background (photo taken in December, 2001) Photo: 2: Signboard, adjacent Blue Lake
Mt Schank is a nearby volcanic cone made up mainly of ash. It contains a dry crater inside its upper rim. Ash and basalt have been quarried from the hill's outer slopes. The hill's volcanic products rest upon a limestone plain of Tertiary age which contains parallel ridges of calcium-rich sand (aeoleanite of Recent age).	Photo 3: Mt Schank, from Blue Lake crater rim