Latest news with #mantle
The Independent
4 hours ago
- Science
- The Independent
The deep Earth discovery that could put a new ocean where a continent is
Scientists have detected rhythmic surges of molten mantle rock, described as similar to a heartbeat, deep beneath the African continent. These upward-surging pulses of hot mantle could eventually lead to the continent tearing apart and the formation of a new ocean over millions of years. Evidence for this phenomenon was found in the Afar region of Ethiopia, a triple junction where three tectonic rifts converge. Emma Watson, lead scientist of the study published in journal Nature Geoscience, explained that the mantle beneath Afar is not static but pulses, with these ascending molten channels being guided by the overriding rifting plates. The research highlights how deep mantle upwellings are linked to plate motion, influencing surface volcanism, earthquake activity, and the process of continental breakup. Something is 'pulsing' beneath the Earth, scientists say – and could tear a continent apart
Yahoo
6 hours ago
- Science
- Yahoo
Something is ‘pulsing' beneath the Earth, scientists say – and could tear a continent apart
Scientists have detected deep pulses in the Earth beneath Africa – and it could tear the continent apart. The pulses are made up of molten mantle rock surging in rhythm, the researchers say. The plume of hot mantle is surging upwards in pulses that are like a heartbeat, they say. Eventually, the continent will be torn apart and a new ocean will be formed. That will take place over millions of years, as the tectonic plates are ripped apart at rift zones like those in the Afar region in Ethiopia. That is where scientists found the evidence of the unexpected behaviour. 'We found that the mantle beneath Afar is not uniform or stationary – it pulses, and these pulses carry distinct chemical signatures,' said Emma Watson, the scientist who led the study. 'These ascending pulses of partially molten mantle are channelled by the rifting plates above. That's important for how we think about the interaction between Earth's interior and its surface.' In the research, scientists gathered samples from the Afar region, where three tectonic rifts meet. Scientists have long thought that mantle was being pushed up making the crust extend, eventually giving birth to a new ocean basin, but did not know how it was happening. To better understand that process, they took those samples and combined them with existing data and models to understand the plume beneath the surface of the Earth. They showed that there is one asymmetric plume beneath the surface. 'We have found that the evolution of deep mantle upwellings is intimately tied to the motion of the plates above. This has profound implications for how we interpret surface volcanism, earthquake activity, and the process of continental breakup,' said Derek Keir, a co-author. '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,' The work is described in a new paper, 'Mantle upwelling at Afar triple junction shaped by overriding plate dynamics', published in the journal Nature Geoscience.
The Independent
6 hours ago
- Science
- The Independent
Something is ‘pulsing' beneath the Earth, scientists say – and could tear a continent apart
Scientists have detected deep pulses in the Earth beneath Africa – and it could tear the continent apart. The pulses are made up of molten mantle rock surging in rhythm, the researchers say. The plume of hot mantle is surging upwards in pulses that are like a heartbeat, they say. Eventually, the continent will be torn apart and a new ocean will be formed. That will take place over millions of years, as the tectonic plates are ripped apart at rift zones like those in the Afar region in Ethiopia. That is where scientists found the evidence of the unexpected behaviour. 'We found that the mantle beneath Afar is not uniform or stationary – it pulses, and these pulses carry distinct chemical signatures,' said Emma Watson. 'These ascending pulses of partially molten mantle are channelled by the rifting plates above. That's important for how we think about the interaction between Earth's interior and its surface.' The work is described in a new paper, 'Mantle upwelling at Afar triple junction shaped by overriding plate dynamics', published in the journal Nature Geoscience.
Yahoo
12 hours ago
- Science
- Yahoo
Something Strange Is Happening 1,700 Miles Beneath Your Feet. Now We Know Why.
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: Over a thousand miles from the surface, in Earth's D' layer—right on the edge of the liquid metal outer core—there is a weird acceleration of seismic waves. Experiments recreating the phenomenon in a lab found that this is the result of post-perovskite crystals, which form from perovskite. The alignment of these crystals determines their hardness, which then determines how fast seismic waves can move through them. Deep beneath Earth's surface are layers of soil, rock strata often embedded with fossils, gurgling magma, and—back up. Before your Journey to the Center of the Earth mission can get any further, you're going to have to get past flows of solid rock. The D' layer—located between layers of magma above and the liquid rock of the outer core below—has been mystifying scientists for decades. This is in part because if you were to plunge down 2,700 kilometers (1,700 miles), you would be jump-scared by seismic waves that accelerate when they hit the threshold of the D' layer. It used to be thought the reason for this was the mineral perovskite, found in the lower mantle, morphing into a form known as post-perovskite close to the D' layer. But that still wasn't enough to explain the phenomenon. Geoscientist Motohiko Murakami wanted to investigate what could possibly be going on to cause the strange seismic wave acceleration known as the D' discontinuity. Because trekking to the core-mantle boundary (CMB) where the D' layer lies is obviously not an option, he led a team of researchers from Switzerland and Japan in running lab tests and computer simulations to find out what post-perovskite had to do with he unusual increase in seismic waves. Post-perovskite crystals are anisotropic, meaning their physical properties are different when measured in different directions. They have two different types of textures—one comes from transformation (the phase transition from the perovskite phase to post-perovskite), and the other is a result of deformation (when post-perovskite crystals turn to face in the same direction). Murakami and his team found out that it isn't just transformation that causes the rumbling. It actually happens with deformation. 'The deformation-induced texture forms when crystals undergo plastic deformation, causing their orientations to align in specific directions. It is mainly produced by dislocation slip or creep,' Murakami said in a study recently published in the journal Communications Earth & Environment. How post-perovskite crystals are aligned determines their hardness, and the speed at which seismic waves move through them depends on how hard they are. Materials called perovskites can be created from any substances capable of being arranged into the same cubic crystal structure. Perovskite is a calcium titanium oxide mineral (CaTiO3), while post-perovskite is a form of magnesium silicate (MgSiO3) achieved at extremely high pressures. Its crystal structure is orthorhombic, meaning that the right angles of the cubes have unequal axes. For post-perovskite crystals to align with each other, the axes all have to be in the same position. Murakami used MgGeO3 to create crystals analogous to post-perovskite. Like perovskite, MgGeO3 crystals deform easily when pressure is applied, so how they behaved would reflect was is going on over a thousand miles underground. The crystals were heated by a laser, compressed, and heated again to synthesize post-perovskite. They were then exposed to high-pressure sound waves, and the wave velocity was measured once those waves passed through the crystals. It turned out that sound waves can experience a substantial increase in velocity when passing through aligned post-perovskite crystals. Researchers also discovered that the cause of this alignment—which determines the hardness of the material, and therefore the speed of sound waves in the lab and seismic waves deep in Earth—is convection. As hotter material rises, cooler material sinks, as it does in convective storms like hurricanes. Murakami thinks that convection of materials in the mantle (such as plumes rising and slavs sinking) is behind the deformation in the D' layer. This is the first time any evidence—even lab-based evidence—has been found for Earth's innards moving. 'While previous theoretical work has suggested that anisotropy could explain the observed seismic discontinuities,' he said. 'Our results, obtained through in situ measurements of post-perovskite velocities under high pressure, represent the experimental verification of this hypothesis, bridging the gap between theory and observation.' You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
