In Romania is a little known volcano, called Ciomadul, which regularly emits large quantities
of carbon dioxide gas from its shallow magma chamber only 5 kilometers beneath the surface.
Its magma chamber is unusually large, containing 10 cubic kilometers of molten rock.
However, among active volcanoes, other systems around the planet contain even larger bodies
of magma.
For example, the Yellowstone supervolcano in Wyoming has two massive magma chambers
which total 46,000 cubic kilometers of material.
However, this is still not the largest magma chamber on the planet.
For that, we need to travel to a remote location in the central Andes.
There, a large area is being slowly uplifted due to an underlying magma chamber with an
impressive volume of 500,000 cubic kilometers of molten rock.
That is enough volume that if it was to all erupt, it could hypothetically cover the entirety
of the United States in 131 meters or 430 feet of lava.
So, why does this magma chamber exist?
Is there any danger of an eventual eruption?
This video will answer these two questions and discuss this fascinating feature.
This massive magma chamber is located across a wide swath of the Andes mountain range,
where parts of it are located in Chile, Argentina, and Bolivia.
As we zoom in, you can see that this magma chamber is divided into two parts.
The northern section measures 340 kilometer wide and 180 kilometers long.
In total, it covers approximately 60,000 square kilometers, which is about the size of the
entirety of West Virginia.
This massive magma chamber is located underneath the surface at a depth of between 10 and 20
kilometers.
The upper section of the magma chamber contains dacite composition melted rock, while the
rest of the chamber contains andesite composition melted material.
The Altiplano Puna Magma Body has existed for 11 million years, and during this timespan
its magma has fed highly explosive caldera forming eruptions.
Several of these volcanoes, such as the large caldera shown on screen reached the classification
of a supervolcano, as they explosively erupted more than 1,000 cubic kilometers of volcanic
rock.
In total, at least 28 supereruptions, rating on the volcanic explosivity index as 6, 7,
or 8 occurred during this timespan.
To understand why this magma chamber is present, we need to look further back in Earth's geologic
history in a different section of the planet.
Beginning around 40 million years ago in what is now the western United States, a similar
series of events occurred.
At the time, the Farallon tectonic plate was subducting underneath the North American plate
at a very shallow angle.
Due to this shallow angle, very few volcanoes were created.
This process caused an extreme amount of compression, causing the uplift and formation of the rocky
mountains.
However, several million years later, something changed.
The Farallon tectonic plate suddenly snapped downwards at a much steeper angle in a process
called slab rollback.
This caused magma to rush upwards to fill the empty space previously occupied by the
tectonic plate.
Large volumes of magma than creeped through the crust, and erupted onto the surface through
incredibly large volume explosive eruptions.
This geologic event was referred to as the Mid tertiary ignimbrite flare up, which saw
the creation of dozens of supervolcanoes in a short timespan in the southwestern United
States.
The same thing occurred in South America to produce this massive magma reservoir, except
the subducting tectonic plate is the Nazca plate, and the colliding plate is the South
American plate.
We are seemingly in the middle of a long term ignimbrite flare-up, which is currently undergoing
a long pause in activity.
Thus, the underlying magma will eventually intrude shallower into the crust, producing
more massive caldera forming eruptions and new supervolcanoes.
However, we do not know when or where this will occur next.
With this being said, the most likely site of the next eruption is the Uturuncu volcano
located in Bolivia.
Due to the magma intruding into the crust, it represents the center of a long term uplift
which raises the volcano at a rate of 1 centimeter each year.
I hope that you enjoyed this video!
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