It’s pretty common to hear about the heartbeat below our feet because of Mother Earth references, but this time around, people are being quite literal. Deep beneath the surface of Africa, scientists have uncovered a powerful, rhythmic force pulsing beneath their feet, deep within the Earth’s core. In the Afar region in Ethiopia, where three tectonic plates converge, these molten rock plumes fuel intense volcanic and tectonic activity.
The fact is, this pulsing is gradually tearing the continent apart and setting the stage for the birth of a new ocean basin millions of years in the future.
The Afar Triple Junction
At the heart of the East African Rift system lies the Afar Triple Junction, a remarkable geological crossroads where three tectonic plates, the Nubian, Somali, and Arabian plates, are slowly pulling away from one another. The Earth’s crust is being stretched so extensively that it is splitting apart, giving rise to deep cracks, faults, and frequent volcanic activity.
This is one of the best places in the world for researchers to study the early stages of ocean basin formation. The land between these plates is thinning and sinking, making it ready for the eventual creation of a new ocean.
Discovery of the Deep Pulse
Scientists identified distinct chemical signatures that repeat across the rift system by analyzing over 130 volcanic rock samples and integrating geochemical data with advanced modeling. These ascending pulses are linked to the movement of the tectonic plates above, channeled through the thinning and stretching crust.
“We found that the mantle beneath Afar is not uniform or stationary – it pulses, and these pulses carry distinct chemical signatures,” said Emma Watts of Swansea University in the UK. “These ascending pulses of the partially molten mantle are channeled by the rifting plates above. That’s important for how we think about the interaction between Earth’s interior and its surface.”
Chemical Signatures
These chemical bands, detected through detailed analysis of volcanic rock samples, repeat across the rift system and vary in spacing depending on local tectonic conditions. This pattern reveals how the mantle plume is not uniform or static but pulses rhythmically, with each pulse carrying a unique geochemical fingerprint that reflects the composition and dynamics of the molten material rising from deep within the Earth.
“These pulses appear to behave differently depending on the thickness of the plate and how fast it’s pulling apart. In faster-spreading rifts like the Red Sea, the pulses travel more efficiently and regularly like a pulse through a narrow artery.” said geologist Tom Gernon of the University of Southampton in the UK.
The Science of Mantle Plumes
Mantle plumes are towering columns of exceptionally hot, buoyant rock that rise from deep within the Earth’s mantle. They often originate near the core-mantle boundary, some 1,800 miles below the surface. Driven by intense heat and pressure, these plumes ascend through the mantle in narrow, vertical streams, carrying both heat and material upward until they reach the base of the lithosphere.
When a mantle plume touches the overlying crust, the resulting heat can cause the surrounding rock to melt partially, generating magma that fuels volcanic activity and creates geological features.
The Birth of a New Ocean
This is the remarkable start of a brand new ocean forming, and even though it might take millions of years before the process is complete, it gives researchers the perfect opportunity to study the process up close and personal.
The Nubian, Somali, and Arabian plates at the Afar Triple Junction are thinning and stretching the crust so dramatically that, eventually, the land will sink below sea level. When this happens, waters from the Red Sea and the Gulf of Aden will flood the depression, creating a new ocean basin in the heart of Africa.
Volcanic Activity and Surface Transformation
The area has quite a history of massive flood basalt eruptions, which covered vast stretches of land with thick layers of lava over 30 million years ago. These ancient eruptions laid the groundwork for the region’s current topography, with remnants still visible as escarpments, dikes, and shield volcanoes scattered across the Afar Depression.
The remarkable volcanic activity in the area shows just how active and vulnerable this region is, making it the perfect place for researchers to study these events.
The Advanced Techniques Used
Thanks to having some of the best technology at their disposal, these researchers can read the crust of the Earth like a book. Geologists begin by conducting meticulous geochemical sampling, using core drilling and rock collection methods to retrieve samples from the rift’s volcanic and sedimentary layers.
These samples are then analyzed in laboratories using sophisticated techniques like mass spectrometry, X-ray fluorescence, and atomic absorption spectroscopy. These reveal the precise elemental and isotopic compositions as “geological barcodes” for tracing mantle processes.
The Global Significance
As one of the few places on Earth where three tectonic plates actively split on land, it creates a natural laboratory to study the complex interplay between mantle plumes, tectonic stresses, and magmatic processes driving continental break-up. Research shows that the Afar plume’s interaction with the lithosphere creates a unique bi-directional rifting pattern, optimizing the geometry of continental separation and minimizing mechanical resistance.
“The work shows that deep mantle upwellings can flow beneath the base of tectonic plates and help to focus volcanic activity to where the tectonic plate is thinnest. Follow-on research includes understanding how and at what rate mantle flow occurs beneath plates,” said Keir.
The Future of a Splitting Continent
While no one will drop into the ocean anytime soon, the land is splitting apart and creating a whole new ocean. The Afar region’s transformation is a testament to Earth’s ever-changing nature and a reminder of the powerful, unseen forces that shape our world. Rivers will shift, valleys will widen, and new volcanic features will emerge, turning this land into a place entirely unknown to humans today.
