Devil’s Marbles - Karlu Karlu Conservation Reserve: Science, History, and Cultural Heritage

The Devil’s Marbles refers to an area in Australia sprinkled with large reddish boulders. This area is near Wauchope in the Northern Territory, Australia. The aboriginals call it Karlu Karlu and it is part of a conservation reserve, a gem of natural heritage and cultural heritage in Australia.

What makes the Devil's Marbles site special is the presence of hundreds of huge rounded boulders stretching over an area of 18 square kilometers (around 7 square miles). Many of these boulders are as high as 11-12 meters. But that’s not the only thing that’s special about this site. What makes this site unique is the way in which these boulders are positioned. The way they are balanced one on top of the other seems to be defying gravity.

When looking at such an intriguing sight, we have to wonder what makes it possible for the boulders to be positioned in such strange structures? Did someone place them there? Or are there some more natural causes for their shapes and positioning?

We can answer these questions by using some basic science and some details about our planet’s history.

How were the Devil’s Marbles formed?

Like every other geological wonder, Devil’s Marbles has a long history. Its history goes back in time even further than the Eye of the Sahara, another interesting geological marvel of our planet. The inception of Devil’s Marbles dates back to about 1.6 billion years ago.

Around that time, the magma in the Earth’s crust in that region solidified forming the igneous rock that makes up these large boulders. More specifically, it’s a coarse-grained igneous rock called granite.

The main minerals present in the composition of granite rocks are quartz and feldspar, both of them being silicate minerals. Quartz contains in its structure oxygen and silicon, the two most abundant elements in the Earth’s crust. Feldspars are also silicate minerals, but besides oxygen and silicone, they also contain other chemical elements, such as aluminum, sodium, potassium, and others, forming more complex structures.

The science behind the Devil's Marbles' color

Depending on the proportion of these main minerals and some other present minerals, granite rocks can have different colors. The pink-to-red color in granite rocks comes from the higher abundance of potassium feldspar in the granite rock composition. Deeper red hues of granite could also come from the presence of iron oxide in hematite grains present in the rock.

If you want to admire the Devil’s Marbles under the finest display of pink and red hues, the best time to visit the site is during sunrise or sunset, when the reddish color is especially intense.

What is the cause for the Devils’ Marbles shapes?

The Devil's Marbles history started when the magma in the Earth’s crust solidified forming the granite rocks in that region. These rocks were formed beneath a layer of sandstone, which was applying extensive pressures to the granite rock. However, in time, over many millions of years, the weathering conditions in the area caused the gradual erosion of the sandstone layer. With the sandstone layer gone, all the pressure it was applying to the granite mass was also gone, leaving behind granite layers with varying degrees of cracks in them.

The horizontal and vertical cracks that formed over long periods of time, and under the effect of weathering agents, started shaping the granite block into rectangular structures. The weathering process continued over millions and millions of years. Since granite is a much harder rock that sandstone, its weathering is a much slower process than that of sandstone. So while the weathering agents lead to the full erosion of the sandstone layer, their effect on the granite blocks was much smaller, yet still quite noticeable.

It was the action of water, wind and extreme temperature changes in the region that carved the rectangle granite blocks into the round-shaped boulders we call the Devils’ Marbles.

Where does the name Devil’s Marbles come from?

To find out the meaning behind the name, we have to switch from the scientific point of view to a cultural one. We need to understand the cultural heritage aspect of the site.

The name “Devil’s Marbles” dates back to the year 1870, when an explorer that was surveying the area said, “This is the devil’s country; he’s even emptied his bag of marbles around the place.”

So that is where the name “Devil’s Marbles” came from. But in the aboriginal culture, the site is named Karlu Karlu, which translated means “round boulders”. The Karlu Karlu Conservation Reserve is a Registered Sacred Site, and it is of high cultural significance for the local Alyawarre people as well as for other Aboriginal groups.

In the traditional culture, the Devil’s Marbles were created by an ancient ancestor of the local people, named Arrange or the Devil Man.

The Arrange legend says that one time when Arrange walked through the area, he made a hair belt. This is something that is only worn by initiated Aboriginal men. As he was creating this hair-string belt, some hair clusters dropped to the ground. These large chunks of his hair then transformed into the big red boulders we now call the Devil’s Marbles.

Before returning to his home in the Ayleparrarntenhe hill east of the reserve, Arrange also spat on the ground, his spit forming the boulders at the center of the reserve. The legend says that Arrange still resides in the Ayleparrarntenhe hills.

If you’re ever in the area, take the time to admire the hard work that both nature and Arrange put into shaping the Devil’s Marbles.

Have you ever been to the Devils’ Marbles site? How was it? If you haven’t been, would you like to go? I would love to visit the site, not just because of its interesting geological history, but also because of its cultural heritage significance.

*images are from Canva Pro