According to a recent study, scientists have discovered that the continent of Africa is tearing apart due to severe volcanic activity caused by a massive superplume of semi-molten rock. It is believed that this molten rock is rising from the boundary between the Earth’s core and mantle layers, beneath the Earth’s crust in Africa. This is responsible for the breaking up of the African continent into two parts. This activity cannot be regarded as a mere geological phenomenon; rather, it represents Earth reshaping its own structure, resulting in a new map.
According to experts, the continent of Africa will be divided into two land masses joined by an ocean. However, this will take several million years. Geological models indicate that this transformation will occur gradually through continuous crustal thinning, faulting, volcanism, and eventual seafloor spreading, similar to how the Atlantic Ocean was formed.
Background
Researchers stated that it has long been known that the region of the East African Rift System (EARS) is slowly ripping apart. However, the main point of discussion was the catalyst that triggered this colossal continental drift. Earlier, scientists were of the opinion that tectonic plates were responsible for splitting up of Africa. These are the same tectonic plates that created large mountains through collision and vast basins through their disintegration.
The Latest Developments
Now, as per the recent study conducted at the University of Glasgow, an international team of geologists led by Professor Fin Stuart have come up with the newly discovered evidence which proves the splitting up of Africa. Chemical analysis of volcanic gases from Kenya is the first evidence that an enormous superplume is thrusting against the Earth’s crust of Africa and is slowly separating the Somali plate and the Horn of Africa from the rest of the continent. That is, the African divide may be driven by intense volcanic eruptions taking place deep under the Earth’s crust.
The study further suggests that this superplume is not static but dynamic, sending pulses of hot material upwards, which interact differently with the overlying crust depending on its thickness and composition. These pulses influence the point where rifting and volcanism are strongest.
Key Scientific Evidence and Research Insights
The study was conducted at the University of Glasgow and the Scottish Universities Environmental Research Centre (SUERC). According to Fin, scientists have long been curious to know about the manner in which the deep Earth comes up to the surface, the extent to which deep Earth material is displaced, and the role of the deep Earth in the formation of extensive Earth topography.
At present, geologists have revealed the importance of volcanic gases that support the theory. According to scientists, there is a certain chemical element, found in gases obtained at the Menengai Geothermal Field located in central Kenya. This element is likely to have been discharged from the deep mantle layer of Earth, i.e., the region lying between the lowest part of the mantle and the core.
Further, researchers working at the University of Glasgow in Scotland stated that this element is the same as that present in gases found in volcanic rocks in Malawi, located south of central Kenya, and volcanic rocks in the Red Sea, located to its north. This implies that all these places lie on the same mantle rock, situated deep beneath the Earth’s crust.
According to the co-author of the study, Biying Chen, who works at the University of Edinburgh in Scotland as a post-doctoral research associate in the School of Geosciences, scientists have gained insightful information regarding the deep interior of Earth with the help of gases obtained from geothermal wells. Using these findings, researchers will be able to gain a clearer understanding of geological forces, altering East Africa as well as the primary processes that lead to the development of the Earth’s surface over many centuries.
He further stated that there is a considerable similarity among the mantle signatures obtained from different sections of the EARS. This implies that their origin lies in the same location of the deep mantle. All the findings of the study were published in the journal titled Geophysical Research Letters.
What is EARS?
EARS refers to a continental rift system on Earth that is the largest and most active. It splits the African continent for around 2,175 miles (3,500 km). For almost 35 million years, the Earth’s crust and upper mantle layers, i.e., the lithosphere, have been tearing apart throughout the rift. Due to this gradual break-up of the lithosphere in Africa, a network of valleys has formed, beginning from the Red Sea, which is off the coast of North-East Africa, and continues up to Mozambique located in southern Africa.
According to the earlier research carried out by scientists, there were several indicators that proved the existence of a deep mantle plume beneath the EARS. These indicators were present in the signatures of noble gas. However, these geochemical tracers (or Noble gases) were insufficient and often irregular beneath the EARS.
Do You Know?
Noble gases such as helium, neon, argon, xenon, etc., are generally inactive (chemically inert) and are generally found in trace amounts in the atmosphere. This means, there is commonly no chemical reaction between these gases and other substances. So, these gases are available for a long duration and can be easily employed for tracing geological processes that are long-lasting.
Analytical Methods and Geochemical Techniques Used under the EARS
Certain high-precision instruments were used by the team to analyse conditions beneath EARS. Using these instruments, they searched for neon (Ne) isotopes in Kenyan gases. To their surprise, they found a deep mantle signature in the gases which highly resembled with a large number of ancient surface signatures found in Hawaii. It is believed that Hawaii is also located above a deep mantle plume.
Chen stated that discovering the initial Ne isotope data that reflected an ancient deep mantle signature was thrilling. However, his team had to make extensive efforts to analyse this minuscule signature. For several hours, they repeatedly checked and re-checked the data and often doubted the output. It was only after thoroughly examining the data that they were certain about the authenticity of the signature and that it was the same as those present in other regions of the rift.
Chen observed that the origin of the EARS plume is most probably the core-mantle boundary, located at a depth of 2,900 km beneath the Earth’s surface under East Africa. Due to this plume, tectonic plates are moving apart, and the African continent has been lifted up for around hundreds of metres than normal. It was further observed by him that though the signatures of the EARS have considerable resemblance to that of volcanic rocks on Hawaii, there is a slight difference between them. It is projected that Hawaii plume is a narrow stream of hot mantle that rises distinctly, similar to a lava lamp; on the contrary, the EARS plume has a different geometry and appears broader and more dispersed in nature.
According to Chen, the original mantle beneath the EARS has been replaced by a massive influx of hot material rising from deep within the Earth. When this hot molten material comes into contact with the lithosphere that is hard and colder, it expands. As a result, sufficient force is generated to rip apart the thin lithosphere layer of Earth and causes extreme volcanic eruptions in the region.
Frequent oceanic volcanoes are considered echoes of the splitting of ancient continents. A gulf between Asia and Africa is still widening, even 5 million years after it was once thought to have stabilised.
The seven continents of Earth were formed through plate tectonics (historically known as continental drift), and therefore, Earth is already familiar with this process. Around 240 million years ago, there was only one supercontinent, Pangaea, and no humans lived on Earth at that time.
The mountain ranges of Pangaea (also spelt Pangea) consisted of what are now the Atlas Mountains, the Scottish Highlands, and the Appalachian Mountains as a single system. Later, the continental drift spilt them apart.
Conclusion
According to Ken Macdonald of the University of California, the splitting of Africa is occurring at a more rapid pace than previously anticipated. In the future, one continent may comprise Kenya, Somalia, Tanzania, and parts of Ethiopia; while the other smaller continent could be named as Nubian Continent. He further added that the East African Rift Valley may eventually be filled with the waters from the Indian Ocean. As a result, the newly formed ocean could attain a similar depth as that of the Atlantic Ocean.
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