Apacheta-Aguilucho volcanic complex facts for kids
Quick facts for kids Apacheta-Aguilucho volcanic complex |
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The Apacheta-Aguilucho volcanic complex is a group of volcanoes in Chile. It's also known as Cerro Pabellón. This complex is made up of two main volcanoes: Cerro Apacheta and Cerro Aguilucho. They are mostly built from flowing lava.
There are also two smaller lava domes nearby, called Chac-Inca and Pabellón. One side of Apacheta volcano shows signs of a huge landslide that happened a long time ago.
These volcanoes were active millions of years ago. But even today, you can see steam vents, called fumaroles, showing that there's still heat underground. This heat comes from a geothermal system. In 2017, the first geothermal power plant in Chile started working here, using this natural heat to make electricity!
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Where is Apacheta-Aguilucho?
The Apacheta-Aguilucho volcanic complex is in northern Chile. It's quite close to the border with Bolivia. The city of Calama is about 105 to 120 kilometers (65-75 miles) southwest. El Tatio, another famous geothermal area, is about 60 kilometers (37 miles) south-southwest.
This area is very remote. Not many people live here, except for those working at the geothermal power plant or in mining. The climate is very dry, or arid. If you see any plants, they are usually just grasses and small bushes.
Part of the Andes Mountains
This volcanic complex is part of the Central Volcanic Zone of the Andes mountains. This zone has many volcanoes. One huge area, called the Altiplano-Puna volcanic complex, had massive eruptions between 10 and 1 million years ago. These eruptions created huge amounts of rock.
Today, the Central Volcanic Zone still has active volcanoes and geothermal fields. All this volcanic activity happens because the Nazca Plate (a large piece of Earth's crust) is slowly sliding underneath the South America Plate. This process is called subduction.
What are the Volcanoes Like?
Apacheta-Aguilucho is made of two composite volcanoes: Cerro Apacheta and Cerro Aguilucho. A composite volcano is tall and cone-shaped, built up by many layers of hardened lava and ash. The highest point of the complex is 5,557 meters (18,232 feet) tall!
The northern volcano, Aguilucho, and the southern volcano, Apacheta, are mostly made of a type of lava called rhyolite in their centers. The outer parts are made of andesite and dacite lavas.
The oldest parts of the volcanoes are very worn down by weather. The two lava domes, Chac-Inca and Cerro Pabellón, are the youngest parts of the complex.
Traces of Ice
You can find signs that glaciers were once here! There are piles of rocks and dirt called moraines to the west and east of the volcanoes. Also, the crater area of Aguilucho shows signs of being shaped by ice. These glaciers were present during the last major ice age.
Hot Spots Underground
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Apacheta volcano has active fumaroles (steam vents) on its northern and eastern sides, and at its top. These fumaroles release very hot steam, around 108-118 degrees Celsius (226-244 degrees Fahrenheit)! The gases coming out are typical of a geothermal system.
This area also has other hot features like mud pools and small vents. All this activity shows that there's an active magma system deep below Apacheta-Aguilucho. When scientists drilled into the ground, they found temperatures over 200 degrees Celsius (392 degrees Fahrenheit) at only 500 meters (1,640 feet) deep!
This underground heat has changed many parts of the volcanic complex. It has created a sulfur deposit on the western side of Aguilucho. There's even a mine called Mina Aguilucho on that side.
The Pabellón Geothermal System
The Pabellón geothermal system was found in 1999. It covers a large area of about 25 square kilometers (9.6 square miles). It's called a "blind" system because there isn't much activity on the surface, even though there are fumaroles at the top of Aguilucho. It's thought that cracks in the ground, called faults, help the gases reach the surface.
Thick layers of clay deep underground act like a seal, trapping the hot water and steam. The heat source for this system is not fully clear. The last eruptions of Apacheta-Aguilucho happened a very long time ago.
What is a Sector Collapse?
A huge landslide deposit stretches 4.5 kilometers (2.8 miles) away from the eastern side of the volcanic complex. This landslide covers about 3 square kilometers (1.1 square miles). There's a large scar on the volcano where the landslide broke away.
This type of landslide is called a "debris avalanche deposit." It leaves behind bumpy hills and often ridges on its sides. These collapses happen for different reasons and are quite common on volcanoes. For example, Mount St Helens in the USA had a similar collapse during its famous 1980 eruption.
For Apacheta-Aguilucho, it's likely that the landslide happened because the volcano's structure became weak. This weakening was probably due to the hot water and steam from the geothermal system changing the rocks. Once the volcano's side failed, the landslide moved eastward.
How the Volcanoes Formed
The Apacheta-Aguilucho volcanic complex formed over several stages, starting millions of years ago.
First, about 7.5 million years ago, a type of volcanic rock called ignimbrite was laid down. Then, andesite lava flows happened about 6.7 million years ago. After that, more lava flows, made of dacite, were put in place.
The Apacheta and Aguilucho volcanoes were built up one after the other. Apacheta is made of lava flows and ash. Aguilucho is also built from lava flows. Finally, the lava domes Pabellón and Chac-Inca formed.
Scientists have dated the rocks to understand when these events happened. For example, some lava flows are about 910,000 to 700,000 years old. The Chac-Inca dome is about 140,000 years old. The Cerro Pabellón dome might be around 50,000 to 130,000 years old.
After the volcanoes stopped erupting, the volcanic activity seems to have moved to a nearby volcano called Azufre. If Apacheta-Aguilucho were to erupt again, it would likely be small explosions, possibly from steam.
Making Power from Earth's Heat
In the 1990s, steam was found while drilling a water well. This led to studies by energy companies like ENAP and UNOCAL. They found the steam vents (fumaroles) and realized there was a geothermal system.
In 2009, a company called Geotérmica del Norte S.A. (GDN), which includes the Italian company ENEL, got permission to use the geothermal system. They started the Cerro Pabellón geothermal power project.
In 2015, they began building two power plants. Each plant was designed to produce 24 MW of electricity. The plant on Pampa Apacheta, about 3.5 kilometers (2.2 miles) east of the volcanoes, was officially opened by the Chilean president in September 2017.
This made it the first geothermal power station in South America! As of 2021, it is still the only one operating there. It's also the highest large-scale geothermal plant in the world, located over 4,500 meters (14,764 feet) high.
The Cerro Pabellón project is expected to produce 340 Gigawatt-hours of electricity each year. This is enough to power about 165,000 families! It also helps reduce Chile's carbon dioxide emissions. In 2019, they started to expand the plant to produce even more power, aiming for 81 MW. The plant also uses hydrogen to store energy.
Images for kids
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The Apacheta-Aguilucho volcanic complex.
See also
In Spanish: Complejo volcánico Apacheta-Aguilucho para niños
