A team from the University of Wollongong in Australia, led by volcanologist Annalise Cucchiaro and geoscientist Nicholas Flament, has linked volcanic eruptions to mantle activity. They have found basal structures in the lower mantle that they have named ‘BLOBS’, which they believe are responsible for the mantle plumes that occur in areas prior to a volcanic eruption. These plumes are related to the virulent eruptions that caused the extinction of the dinosaurs.
According to the study, there are two BLOPs; one is under the African hemisphere, and the other under the Pacific. According to the experts, being able to predict when and how volcanic eruptions will occur could help to find magmatic treasures such as kimberlite and diamonds, which can be used for renewable energy consumption.
Volcanic eruptions
Volcanic eruptions are geological phenomena known to cause emissions of lava and volcanic gases at the earth’s surface, through the formation of a volcano. A volcanic eruption as such occurs when magma rises from the center of the earth and reaches the surface. Its origin is associated with an increase in temperature and gas pressure in a magma mass in the Earth’s mantle.
Lower mantle
The lower mantle is the inner layer of planet Earth, ranging from 660 kilometers to 2900 kilometers deep. It is located just above the core but below the transition zone, and is characterized by being mostly solid, due to pressure. Its temperature is between 1000ºC and 3000ºC. It is composed mainly of dense rocks rich in iron and magnesium, and unlike how it is represented in books, it is a surface with rocky structures and slopes.
New investigations
Now that the main concepts are defined and clarified, what has been discovered? The devastating consequences of a volcanic eruption are well known. They go beyond physical destruction, as they also involve the closure of entire cities, cancellation of air traffic, altering the climate, and even ending life on the planet as happened with the dinosaurs. Researchers have been able to relate eruptions to certain features present in the deep Earth, which may shed some light when it comes to forecasting them.
BLOBS
A team from the University of Wollongong in Australia, led by volcanologist Annalise Cucchiario, has made a discovery that could be of great help. These basal structures found in the lower mantle, mimicking small mountains, have been named BLOBS, and they have been able to relate them to volcanic activity. The study explains that when the so-called deep mantle plumes rise from depths of nearly 2,000 miles (3,000 kilometers), they give rise to the most virulent and destructive type of volcano.
Researchers have linked the plumes to BLOBS, considering the latter as possible sources of the plumes. According to Cuccchiaro and his team, data on large eruptions 300 million years ago have helped confirm this new theory. According to the volcanologist, “This work highlights the importance of mantle plumes in acting as ‘magmatic highways’ to the surface, creating these giant eruptions”.
Simulating BLOBS
According to the study, there are 2 BLOBS: one located under the Pacific hemisphere and the other under the African hemisphere. Although the plumes have been shown to move along with their BLOBS, it has not yet been determined whether the BLOBS are static or moving. The team carried out a series of simulations of the supposed BLOBS millions of years ago, showing that they produced these plumes in the mantle, which were tilted as they rose to the surface. What does this mean?
That the researchers can say with certainty that the eruptions occurred near or even above the BLOBS. Cuccchiaro and Nicholas Flament, a geoscientist on the study, explained in The Conversation that “We use statistics to show that the locations of past giant volcanic eruptions are significantly related to the mantle plumes predicted by our models,” adding, “This is encouraging, as it suggests that the simulations predict mantle plumes at locations and times generally consistent with the geologic record”.
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