Latest news with #BLOBS
The Sun
3 days ago
- Science
- The Sun
Map of Earth's underworld shows hidden ‘blobs' blamed for wiping out almost all life & killing the dinosaurs
MYSTERIOUS 'BLOBS' lurking beneath the Earth's surface could be responsible for the cataclysmic volcanic eruptions that helped kill off the dinosaurs. While an asteroid impact was the main force behind the demise of the dinosaurs, a chain of violent volcanic eruptions that followed the impact is also thought to have played a role. 4 4 4 Volcanic eruptions can wipe out entire cities - just look at Pompeii - and even wipe out life on Earth. The source of these Earth-shattering eruptions can be traced back to specific features deep within Earth's underworld, called 'BLOBS', according to a new study. These so-called 'BLOBS' - which stands for big lower-mantle basal structures - lie thousands of kilometers below Earth's surface. And they move just like the tectonic plates above them. There are two giant 'BLOBS' that are both the size of continents hiding under the African and Pacific hemispheres, researchers said. Volcanologist Annalise Cucchiaro from the University of Wollongong in Australia, discovered these 'BLOBS' with her colleagues. They say these deep Earth structures have a direct influence on volcanic activity above ground. Giant volcanic eruptions occur when deep mantle plumes - scorching columns of rock - rise from nearly 3,000 kilometers below the surface. Analysing three different datasets on large volcanic eruptions that occurred around 300 million years ago, the researchers concluded that the 'BLOBS' are the source of these plumes. "This work highlights the importance of mantle plumes in acting as 'magma highways' to the surface, creating these giant eruptions," Cucchiaro said in a statement. World's smallest volcano found by locals after bursting from ground in Peru "It also shows that these plumes move along with their source, the BLOBS." Although some mysteries remain - like whether the BLOBS are fixed in place or if they travel across the underworld. "This research cracks open one of the questions that has long plagued scientists – are the BLOBS stationary or mobile and how do they relate to giant volcanic explosions – so it is a thrill to finally [be able] to unravel these mysteries," added geoscientist Nicholas Flament. What the new research suggests is that they are part of a dynamic system that has direct repercussions for all living things above ground. "We used statistics to show that the locations of past giant volcanic eruptions are significantly related to the mantle plumes predicted by our models," Cucchiaro and Flament wrote in The Conversation. "This is encouraging, as it suggests that the simulations predict mantle plumes in places and at times generally consistent with the geologic record." With all the devastation volcanic eruptions can cause, it is important to know what causes them to blow.
The Independent
7 days ago
- Science
- The Independent
Scientists discover the ‘missing link' that causes giant volcanic eruptions
Volcanic eruptions at Earth's surface have significant consequences. Smaller ones can scare tourists on Mount Etna or disrupt air traffic. Giant, large-scale eruptions can have more serious impacts. One such event contributed to the demise of the dinosaurs 66 million years ago. Giant volcanoes also triggered events that led to the largest mass dying on Earth, the Permian–Triassic extinction 252 million years ago But what fuels a giant eruption, and how does it make its way to the surface from deep within the planet? In a new study published in Communications Earth and Environment, we show that columns of hot rock, which rise some 3,000 kilometres through Earth's mantle and cause giant eruptions, are connected to continent-sized source regions we call BLOBS. Hidden blobs within Earth BLOBS are hot regions at the bottom of Earth's mantle (between about 2,000km and 3,000km in depth) which might be composed of different material compared with the surrounding mantle rocks. Scientists have long known about these two hot regions under the Pacific Ocean and Africa. Geologist David Evans from Yale University suggested the acronym BLOBS, which stands for Big LOwer-mantle Basal Structures. These BLOBS have possibly existed for hundreds of millions of years. It is unclear whether they're stationary or if they move around as part of mantle motion (called convection). Mantle plumes were the implicit link in previous studies relating BLOBS to giant volcanic eruptions. Their shape is a bit like a lollipop: the 'stick' is the plume tail and the 'candy' is the plume head. Mantle plumes rise very slowly through the mantle because they transport hot solid rock, not melt or lava. At lower pressures in the uppermost 200km of Earth's mantle, the solid rock melts, leading to eruptions. A long-sought relationship In our new study, we simulated mantle convection from one billion years ago and found that mantle plumes rise from moving BLOBS and can sometimes be gently tilted. Giant volcanic eruptions can be identified by the volume of volcanic rocks preserved at Earth's surface. The ocean floor preserves detailed fingerprints of mantle plumes for the past 120 million years or so (there is not much seafloor older than that). Oceanic plateaus, such as the Ontong Java-Manihiki-Hikurangi plateau currently in the southwest Pacific Ocean, are linked to plume heads. In contrast, a series of volcanoes such as the Hawaii -Emperor seamount chain and the Lord Howe seamount chain are linked to plume tails. We used statistics to show that the locations of past giant volcanic eruptions are significantly related to the mantle plumes predicted by our models. This is encouraging, as it suggests that the simulations predict mantle plumes in places and at times generally consistent with the geologic record. Are BLOBS fixed or mobile? We showed that the considered eruption locations fall either onto or close to the moving BLOBS predicted by our models. Eruption locations slightly outside moving BLOBS could be explained by plume tilting. We represented fixed BLOBS with 3D images of Earth's interior, created using seismic waves from distant earthquakes (a technique called seismic tomography). One out of the four seismic tomographic models that we considered matched the locations of past giant volcanic eruptions, implying that the fixed BLOBS scenario cannot be ruled out for geologically recent times – the past 300 million years. One of the next steps for this research is to explore the chemical nature of BLOBS and plume conduits. We can do so with simulations that track the evolution of their composition. Our results suggest the deep Earth is dynamic. BLOBS, which are some 2,000km below Earth's surface, move hundreds of kilometres over time, and are connected to Earth's surface by mantle plumes that create giant eruptions. To take a step back and keep things in perspective: while deep Earth motions are significant over tens of millions of years, they are generally in the order of 1 centimetre per year. This means BLOBS shift in a year at roughly the rate at which human hair grows each month. Nicolas Flament is an Associate Professor and ARC Future Fellow in Environmental Futures, School of Science at the University of Wollongong.
