Summary: Geological History Of The Australian Alps

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Mt Kosciusko Field Trip Report Geological History of the Australian Alps The geological history of the Australian Alps starts when the majority of east Australia was submerged underwater at around 800 million years ago. At this time there were large sediment layers that covered the sea floor. By around 450 million years ago, the earth began to move underneath the continental plate causing uplifting and folding (Australian Alps National Parks, 2010, Geology and geomorphology of the alpine landscape para.6). Magma rose up through the layers at temperatures reaching up to 1000°C. The magma that reached the sea bed due to weakness in the crust cooled quickly and formed a layer of basalt above the sediments (see diagram 1). Other magma intrusions…show more content…
When the glacier stopped, the sediments that had built up during the glacial movement are now dumped at the end of the glacier forming a moraine. The slow moving bottom of the glacier now plucks out loose rock material behind the moraine that is forming at the front (Charles Sturt University, Glacial Landforms and Formations, 2011 p2). This movement causes further material to be removed from the ground and moved to the front. Gradually, a large kettle is formed just behind the terminal moraine of the glacier. When the glacier melted the kettle filled with water and grew dude to further weathering. The result is the lake and the remnant terminal moraine visible in Figure 3 at Headley…show more content…
Phyllite. Like granite there were two types of phyllite found in the national park. Phyllite is a medium grade metamorphic rock with fine grain structure. It is formed from larger temperatures and heavier pressure effects than slate. In the Australian Alps, the phyllite would have formed in a layer lower than the lesser metamorphic rocks. This can be seen in figure 9. The other type of phyllite has quartz veins running through it and was seen earlier along the track than the phyllite in figure 9. When cracks are exposed in the phyllite, water flows in and leaves behind particles. If this water contains amounts of silica when it flows through, the mineral quartz is formed in its place when it reacts with oxygen and is left over time. This combination of quartz and phyllite is seen in figure
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