Earth's 5 oldest mountains and their incredible impact on life on this planet

• Journey back in time with Interesting Engineering (IE) as we reveal Earth's oldest mountains.
• Many ancient mountains have suffered significant erosion, and some are no longer visible from the ground.
• Discover how mountains provide valuable insight into Earth's geological history and significant implications for life as we know it. 

When it comes to the magnificence of Earth's natural environment, mountains are among our planet's most remarkable and majestic landforms. They are home to various resources and ecosystems fundamental for supporting life and have the power to affect our climate. Some are part of natural geopolitical boundaries, while others attract climbers willing to risk their own lives.

But did you know that mountains also have much to tell us about the planet's most ancient past (in geological terms)? The truth is, we know that some of Earth's oldest peaks have existed for billions of years; thanks to geologists who date the rocks, they are comprised using a science known as geochronology. Many of these mountains have suffered significant erosion, and some are no longer even visible from the ground.

Now journey back in time with Interesting Engineering (IE) as we reveal Earth's oldest mountains, including the Barberton Greenstone Belt, the Hamersley Range, the Waterberg Mountains, the Magaliesberg, and the Guiana Highlands.

What are mountains?

Mountains are prominent landforms that rise significantly above the surrounding terrain. According to National Geographic, a mountain typically reaches an altitude of at least 1,000 feet above sea level. A group of closely spaced mountains is referred to as a mountain range.

Mountains can range from steep and jagged peaks to gentler, rolling hills. They can be found on every continent, under some oceans, and play a significant role in the Earth's geology, ecology, and culture. 

The formation of mountains is a result of tectonic activity. For details on mountain-forming processes, check out our full explainer here.

What are the oldest mountain ranges on Earth?

The top five mountain ranges containing the oldest rocks on Earth are covered in the section below. Many of these have been included on UNESCO's list of World Heritage Sites, which comprises unique sites worldwide thought to be of "Outstanding Universal Value" to all humanity. It is important, though, to understand that the entire range may not be as old as the oldest rocks it contains. In fact, tracing a range's timeline can be complicated as ranges can both rise and fall over time.

1. Barberton Greenstone Belt – 3.6 billion years old

The Barberton Greenstone Belt is one of the oldest mountain ranges in the world, estimated to be around 3.6 billion years old. It is located in South Africa and Swaziland and is known for its well-preserved rock formations.

The highest peak in the range has an elevation of about 5,900 feet. The average height of the range is around 2,000-5,900 feet, and it covers an approximate area of 6,177 square miles.

The Barberton Makhonjwa Mountains, outcrops of the Barberton Greenstone Belt, were previously added to UNESCO's list of World Heritage Sites in 2008.

2. Hamersley Range – 3.4 billion years old

The Hamersley Mountain Range is estimated to be around 3.4 billion years old. It is located in Western Australia and is known for its unique geology and mineral resources. 

This range's highest peak is Mount Meharry, with an elevation of around 4,100 feet. The average altitude of the range is around 450-550 meters, and it covers about 160 miles.

3. Waterberg Mountains – 2.7 billion years old

This ancient mountain range is estimated to be around 2.7 billion years old. It is located in Limpopo province, South Africa, covering approximately 5,598 square miles. 

The highest peak in the Waterberg Mountain range is Geelhoutkop, which has an elevation of around 6,000 feet, while the average height is around 600 meters.

Waterberg was the third area in South Africa to receive an official designation of 'Biosphere Reserve' by UNESCO in 2001. As the name Waterberg implies, some mountains from this range serve as water reservoirs for these arid regions.

4. Magaliesberg – 2.3 billion years old

Another ancient mountain range in South Africa is Magaliesberg, estimated to be around 2.3 billion years old. The range's highest peak is Nooitgedacht, with an altitude of 1,852 meters. 

The average elevation of the range is about 300 meters, and it covers an approximate area of 46 miles.

Some regions of the Malaliesberg mountain range were also designated as a 'Biosphere Reserve' by UNESCO. The rich biodiversity of the area includes 443 bird species, representing 46.6% of the total bird species in the southern African sub-region.

5. Guiana Highlands – 2 billion years old

The Guiana Highlands are estimated to be around 2 billion years old. They are located in Northeastern South America and cover parts of Venezuela, Brazil, Guyana, and Suriname, covering approximately 1,200 miles. 

The average range elevation is 2,600-4,900 feet, while the highest peak in the range is Pico da Neblina, with an altitude of around 9,825 feet.

The oldest mountain ranges in the world

While the top five oldest mountains on Earth have been revealed above, other ancient mountain ranges do exist:

Guiana Highlands – 2 billion years old

Black Hills – the core is around 1.8 billion years old

Aravalli Range – the fold belt formation is about 1.8 billion years old, although the mountains we see are around 370 million years old.

St. Francois Mountains – around 1.4 billion years old

Mount Pilanesberg in the Witwatersrand Range – around 1.2 billion years old

The Blue Ridge Mountains in the Appalachians – began forming around 1.2 billion years old

Genesis of life

The Barberton Greenstone Belt in South Africa is believed to be the oldest mountain range to be discovered by humans. 

The Barberton Greenstone Belt, also referred to as the Makhonjwa Mountains, is a mountain range comprised of rocks that date from about 3.6 billion years ago. This range is also notable for being the site of the first discovery of gold in South Africa in 1875. 

The highest point of the Makhonjwa Mountains reaches an altitude of approximately 1,800 meters above sea level.

This range is also referred to as the ‘Genesis of Life’ because its geology includes the best preserved ancient Achaean rocks on Earth. These ancient rocks contain a record of the earliest life forms on the planet, bacteria microfossils, as well as evidence of a massive meteorite impact which may be related to the formation of our moon.

What is the significance of ancient mountains?

Revealing ancient secrets 

Studying ancient mountains is significant for understanding the Earth's geological history. Ancient mountains indicate that plate tectonics have been moving for billions of years.

Studying these mountain ranges can also provide information about past climate and atmospheric conditions – as their rocks record all of this! This information is crucial for understanding the evolution of life on Earth and the circumstances that allowed for the development of complex life forms.

It also reveals past extinction events and how Earth experienced climate changes in the past.

Climate control

Mountains play a crucial role in shaping local and global climate patterns. They act as barriers, blocking or slowing down the movement of air masses, which can lead to different climate conditions on either side of a mountain range. 

For instance, when air is forced to rise on one side of the mountain, it may cool, and water vapor condenses into water droplets. This forces the air to release rain that would have been carried farther inland if it were not for the mountains. 

As a result, regions such as the Pacific Northwest, southern Chile, Scotland, and Japan receive more rainfall than they would if they were not mountainous.

Similarly, because mountains can force air masses to shed moisture, regions downwind of mountains tend to be arid. Examples include Nevada, much of Utah, and eastern Oregon in the United States.

Without mountains, global weather patterns would likely be more uniform, with less variation in temperature and precipitation.

Supporting life

Although mountains only make up around 25 percent of Earth's geographical area, they are home to more than 85 percent of the world's amphibian, bird, and mammal species, many of which are unique to such regions. 

Ancient mountains hold cultural and spiritual significance to the local communities living amongst them. For example, holy places exist at some summits, like Doi Suthep near Chiang Mai in northern Thailand. People may consider them to be "closer to God," who resides in the heavens. Some mountains also have religious significance for Buddhist, Jewish, and Christian traditions. 

Evidence that Earth is still evolving  

Also, understanding the formation and history of ancient mountains can aid in studying current tectonic activity and the potential formation of future mountains. 

After all, when we think of mountains, we may imagine them as steady, enduring elements of our landscapes. Geology, however, demonstrates that this is untrue. The tectonic plates that make up our planet's rocky crust are constantly moving, causing changes to the surface of our globe.

Mineral and water resources

Another vital aspect of ancient mountain ranges is their mineral resources. These resources are formed during mountain formation and are of great economic and social importance. 

For example, the Barberton Greenstone Belt is known for its gold deposits, while the Aravalli Range is rich in copper, lead, and zinc. Studying ancient mountain ranges can also lead to the discovery of mineral resources vital for modern society. 

From their highest peaks to the deepest valleys, mountains also serve as a reservoir of water in the form of snow, springs, rivers, and mountain aquifers. In fact, mountain meltwater, runoff, and other freshwater sources provide up to 60-80 percent of the world's freshwater supplies. At least 50 percent of the world's population relies on mountain ecosystems for survival, including food, clean energy, and water.

Earth's oldest mountains: concluding notes 

In conclusion, studying ancient mountain ranges is an essential yet fascinating field in geology. The oldest mountains on Earth, such as the Barberton Greenstone Belt, provide valuable insight into its geological history and have significant implications for life as we know it. 

Additionally, ancient mountain ranges are also of great economic and social importance due to their mineral resources. Understanding the formation and history of ancient mountains is crucial for understanding the Earth's geological past and predicting future tectonic activity.