Glen Helen Gorge - 🌏 EarthCache EarthCache

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Welcome to

Glen Helen Gorge - EarthCache

A simple EarthCache to bring you here and to highlight this beautiful waterhole edged by red quartzite cliffs and the landform that has formed here over the millions of years

The Western Arrernte Aboriginal people have lived in the Glen Helen region for tens of thousands of years. To them the gorge is called Yapalpe and the Finke River is known as Larapinta which appropriately means 'serpent'. It is known that Glen Helen gorge was a favourite meeting place for the Arrernte from the West and Central MacDonnell Ranges.

The geology of Glen Helen Gorge dates its origins to around 500 million years ago when sandstone was deposited by a shallow sea which flooded much of central Australia. The Finke River, which has long been cited as "the oldest river in the world" cuts through here. The Finke flows through deeply incised meanders. Because meanders only form on flat plains, the river must have formed before the ranges were pushed up before the Alice Springs Orogeny. At that time the river had enough energy to keep pace with the mountain building phase and it was able to incise down through the rocks that were rising underneath it and it ended up cutting out the gorge and a path across the desert to Lake Eyre.

The Alice Springs Orogeny was centered in an area that had previously been a marine sedimentary basin, and involved the thrusting up of the underlying metamorphic and igneous rocks. It was an event beginning approximately 450 million years ago and concluding about 300 million years ago, and it involved less than 100 km of distributed shortening responsible for the formation of the MacDonnell Ranges area.

These cliffs here are made up from heavitree quartzite which is a very hard rock and it forms well defined upstanding ridges, resisting erosion better than the surrounding smaller layers of sediments laid down during geologic events. It's a quartz-rich sandstone with many grains cemented by quartz or partially re-crystalised to an interlocking crystal mass.

Questions to log this EarthCache

Q1 Looking at the Gorge, desribe the shape of the rocks to the right along the ridge, ie, round, square, rectangle - and how are they different from the rocks at the edge of each side the gorge?

Q2 What event occured and how long did it last that formed what we see today here in the MacDonnell Ranges?

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