Continental Drift: Hotpot And Formation Of The Glasshouse Mountains

Introduction:

26 million years ago, on the coastal plain of the sunshine coast, thirteen mountains were formed and are now known as the glasshouse mountains. These mountains were formed from a hotpot. It is now known that because the mountains are in the middle of the Indo-Australian plate meaning there are no plate boundaries that could cause such a thing as the glasshouse mountains. The hotspot fed lava through weak crust and erupted out of the top of the crust forming all 13 mountains. They range in height from 109m (Mt Elimbah) all the way to Mt Beerwah standing at over 550m tall. The following report will provide a justified explanation to the glasshouse mountains were formed, explain that scientific developments led to the theory of continental drift, analyse the location of the volcanoes along the east coast of Australia and predict the location of the hotspot now and critically evaluate the validity of the explanation provided below.

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The glasshouse mountains were formed 26 million years ago, when the Indo-Australian plate moved over an active hotspot. This hotpot was formed by convection currents in the mantle of the earth. Magma in the mantle rotates when hot, less dense magma from the lower parts of the mantle rises to the surface and cools, it then becomes denser, so it once again falls. Hotspots are caused when a small stream of hot magma is converted upwards, forcing magma through the crust. This magma was constantly being fed through the weak crust on the east coast of Australia and formed the glasshouse mountains (unknown,2019) . However, the plate has now moved completely over the hotpot on the east coast. We know this because magma is no longer being fed through the crust meaning because the volcanoes have not erupted in well over 10 000 years which is the maximum amount of time after its last eruption to be considered extinct.

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Scientific developments have provided evidence that has led to the refinement of continental drift into the plate tectonic theory. Alfred Wegner came up with the theory of continental drift. Continental drift is the theory that continents have moved over millions of years and ending up in a changed position. (Unknown,2019) Wegner believed this because of the similarities in the coastlines of Africa and south America which fit together in a jigsaw, fossil evidence and rock and land formations. He believed that the continents moved through the ocean after once being a supercontinent named Pangea. However, he could not figure out how the continents were moving. Harry Hess was a geologist that mapped the seas floor in the mid-Atlantic ridge. Hess determined that convection currents where the reason for trenches and ridges. chSince then, the theory of plate tectonics has only grown stronger with the added evidence of earthquakes and volcanoes being mapped.

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The volcanoes that are located on the east coast of Australia are places in three major vertical lines that move over to the left as they go further south. This can be seen in diagram two of the task sheet. The diagram shows the locations of the hotpot has been previously and shows us which direction it is heading. Because of this diagram, it is predicted that the hotpot is somewhere near Tasmania. Most likely just above it and under Victoria. It is believed that the hotpot is located on the continental shelf just off the northern coast of Tasmania. We can see that it started in north Queensland and has moved south all the way down to Victoria/Tasmania. It is also likely to be future volcanic activity on the continental shelf as the hotpot may not be extinct as it has been active in the last 10 000 years.

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The hotspot is currently located in the continental shelf between Victoria and Tasmania. The hotpot is not in eastern Australia. This is known because the plate is moving north-east and the hotpot is well past eastern Australia. Although the hotpot has not been active for quite some time it is believed that there will be future volcanic activity. This is because the hotpot may not of moved and is just waiting for some weak continental or oceanic crusts so it can pierce through once more and continue to feed magma through. These volcanoes have formed on the east coast of Australia and is now moving south, west. There is also the possibility of a new hotspot forming anywhere in the region as well as the possibility of subduction occurring as the Indo-Australian collides into other plates. With all these options it is most certain that there will be volcanic activity off the east coast/southern coastlines of Australia. (Lulu Morris, 2017)

Conclusion:

In conclusion, it can be seen that a hotpot was definitely the reason for the formation of the glasshouse mountains and not because of subduction. It can be seen that Alfred Wegner was the man that came up with the theory of continental drift and was only slightly incorrect on how it worked. It can be seen that the hotspot is located on the continental shelf in between Tasmania and Victoria. Finally, we can see that there is always the possibility of future volcanic activity on the Indo-Australian plate due to subduction or a new hotspot being formed.

Bibliography:

1. Lulu Morris 2017, Should Australia Expect a volcano eruption? National Geographic, viewed 4 June 2019.
2. Unknown 2019, What is a volcanic hotspot? National Oceanic and Atmospheric Administration, viewed 7 June 2019.
3. Unknown 2019, Who was Alfred Wegener, Encyclopedia Britannica, viewed 4 June 2019