The Australian AlpsThese rocks are found in Australia’s Kosciuszko National Park, home to the highes

The Australian AlpsThese rocks are found in Australia’s Kosciuszko National Park, home to the highest peak in Australia, Mount Kosciuszko. Southeastern Australia is a geologically interesting area. It contains the Australian Alps, a range with several peaks over 2000 meters above sea level.The Australian Alps have an interesting geologic history. They’re a range of peaks sitting close to the coastline, implying a relationship to the opening of the Tasman Sea to the East. Mount Kosciuszko is made of Silurian and Devonian aged granitic rocks that formed during mountain building event on the coast of Gondwana, the supercontinent Australia was once hooked to. The granites formed at a time when Gondwana was growing as fragments of continental crust ran into its edges. The surrounding rocks were squeezed, faulted, and metamorphosed, building a high mountain range.Although the rocks of Mount Kosciuszko formed in this ancient mountain building event, the ancient mountains eroded away over a long period of calm during the next several hundred million years. The active tectonics that built the mountains ended and the range eroded, exposing the granites and metamorphic rocks at the range’s core.To form the Australian Alps, the rocks had to be uplifted once again. As the supercontinent broke up, magma generated from the Earth’s mantle upwelled and heated the crust. The rocks rose to form a plateau as the land to the east of it rifted away. That land to the east is a province nicknamed Zealandia, which now forms part of New Zealand.Since then, the plateau has eroded, in part during the recent glacial advances, carving the rocks into the topography seen today.-JBBImage credit: http://bit.ly/1w0YN97Read more:http://bit.ly/1COgYTEhttp://bit.ly/1GO2MQU -- source link
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