Thursday, 27 April 2017

The Dolerite Columns of Coastal Tasmania

The coastline of the southern Tasmania is composed of spectacular rock columns that stick out up to 300 meters from the sea level. The geologists call these rocks are “dolerites”, due to its distinctive elongated shape and hexagonal columns. The Mother Nature majestic dolerite columns are probably formed in the Jurassic period, somewhere 185 million years ago during a massive volcanic event that covered up to a third of Tasmania. The doleritic clifts surpass 100 m in topography above the sea along much of the southern and eastern coast of Tasmania, and some singular columns occur as giant “totem poles” standing in the sea.

Dolerites are created when molten rocks pushed up from the deep underbelly of the earth cools rapidly and crystallize to form trifling visible crystals in the rock. However, when the rate of cooling is just right, the rocks trends to shrink in volume, because of creation of cracks. Thus, these cracks let the rocks in the interior to cool, resulting in additional cracks. Though at the end, you get a big block of rock with long vertical and symmetrical cracks creating 5 to 6 sided columns, can be just a few centimeters to over quite a lot of meters in diameter. The columns are actually a part of a continuous formation over 4,000 km long extending from Australia through Tasmania and into Antarctica.

The beautiful columnar rocks are not uncommon, as hundreds of recognized localities throughout the world where you can find them. Moreover, some of these locations are very famous such as The Giant’s Causeway in Ireland, The Devil’s Tower in Wyoming, Los Organos in Spain, and Fingal’s Cave in Scotland. The spectacular formations that, like these in Tasmania make him glorious tourist destinations.

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