La missione Juno della NASA, sotto la guida dello scienziato Scott Bolton del Southwest Research Institute, ha rivelato la struttura interna di Io, la luna di Giove caratterizzata dalla più intensa attività vulcanica dell'intero Sistema Solare. Sottoposta a spaventose forze di marea gravitazionali da parte di Giove, Europa e Ganimede, la roccia di Io subisce un continuo attrito che genera un enorme calore interno. Le rilevazioni dello strumento JIRAM mostrano la presenza di un esteso strato magmatico sottocostale e bacini di lava (paterae) i cui strati superficiali sprofondano ciclicamente nel magma fuso, confermando l'esistenza di un pianeta la cui crosta è in perenne e violenta trasformazione.

L'eau ne fait pas que tomber du ciel et retourner aux océans : elle s'enfonce aussi dans les profondeurs de la Terre. Des géologues viennent de montrer que ce cycle caché était déjà à l'œuvre il y a plus de 3 milliards d'années, révélant une Terre primitive bien plus dynamique qu'on ne l'imaginait.

Yellowstone and other volcanic supereruptions may work completely differently than previously assumed, drawing magma from a wide, shallow pool near the surface rather than from a deep plume, according to an international team of researchers.

The new work on volcanic supereruptions was revealed in a recent paper published in Science, offering new insight into the processes behind these potentially devastating events. This knowledge could be essential to future preparedness operations, allowing geologists to refine supervolcano hazard assessments and plan for eruption risk.

Supereruptions

Over 1,000 cubic kilometers of molten magma, solid rock, and drifting ash are ejected during a volcanic supereruption. The initial detonation of these events poses a sudden threat to the environment and local human activity, but the long-term effects of ash lingering in the air can alter the climate in devastating ways across an even larger area and for a longer duration than the initial physical damage caused by rocks and magma.

Researchers at the Institute of Geology and Geophysics of the Chinese Academy of Sciences (IGGCAS) collaborated with researchers at the University of Illinois Urbana-Champaign to develop a new three-dimensional model of the geodynamics of western North America. Their work models the Earth’s rigid outer shell, the lithosphere, and the convecting mantle beneath it, providing researchers with a new glimpse into how magma is generated beneath these supervolcanoes.

Supervolcanoes

The traditional hypothesis explaining supervolcanoes posited that long-standing liquid magma pockets in the Earth’s crust lie beneath them, accumulating magma until the pressure builds to the point that it breaks through the chamber, causing an eruption, collapse, or crustal failure.

Yet modern research has disputed that claim, arguing that the evidence indicates wide areas of partially molten rock, called magma mush systems, dot the lithosphere rather than distinct liquid chambers. Beneath the lithosphere is the asthenosphere, a layer of ductile rock that flows extremely slowly, which current research suggests feeds supervolcanoes through a mysterious mechanism of partial melting.

Magma moving toward the surface from the asthenosphere interacts with solid rock to create a mushy magma that is orders of magnitude more viscous than liquid magma and more diffusely distributed than the chambers of liquid magma described in the older hypothesis.

North America’s Supervolcanoes

Over the last 2.1 million years, North America’s Yellowstone caldera has produced two of these supereruptions, offering geologists a natural laboratory for studying these catastrophic events. Investigations of the area have uncovered an enormous magma-mush system, with liquid bodies existing only briefly, prior to eruptions. However, the geodynamic processes responsible for the system remained obscured prior to the new model.

The model revealed that the subduction of the Farallon Plate beneath central and eastern North America generates a mantle wind that transports asthenospheric material eastward toward Yellowstone. As buoyant material is pulled down beneath the lithosphere on its slow journey, decompression melting occurs, rather than the earlier suggestion that liquid magma rises from a deep mantle plume. This flow to the east combines with the westward movement of the buoyant lithosphere west of Yellowstone to create a tear in the continental lithosphere through which magma can ascend. 

According to the researchers, their model’s projections are consistent with independent geophysical and geochemical observations, demonstrating the veracity of its physical mechanism for supervolcanoes, rooted in enormous magma-mush systems. They say this mechanism should hold for supervolcanoes worldwide, offering crucial new insights that can be used in disaster preparedness.

The paper, “Tectonic Origin of Yellowstone’s Translithospheric Magma Plumbing System,” appeared in Science on April 9, 2026.

Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.

A Martian meteorite fragment containing unexpected grains of mineral could hold clues to the Red Planet’s geological history, according to an international team of researchers.

Prior to the team’s new paper, which was published in Geochemical Perspectives Letters, the red mineral garnet had never been observed in any martian rock sample. Now, the meteorite discovery provides scientists with new clues to Mars‘ extreme past conditions, over its 4.5 billion-year history, which could include hidden magma sources or ancient impact events.

Garnet and Geology

Although the gemstone garnet can come in many colors, it is best known for its dark red varieties, which were historically popular in ancient Egypt, Rome, and Victorian England. Beyond its beauty, the rock is important for the record it keeps of its birth, providing Earth’s geologists with information on our planet’s tectonic forces, ore-forming processes, and the fluid-rock interactions of the crust and mantle.

Similarly, the small grains of garnet discovered in the meteorite sample contain important data for reconstructing the forces that forged the Red Planet long ago.

“The findings add a striking new dimension to our understanding of the geology of Mars and open an exciting new window into the evolution of our planetary neighbour,” said co-author Professor James Darling.

“This discovery is going to expand our knowledge of the geologic processes that are possible on this planet,” said lead author Tanya Kizovski, Assistant Professor of Earth Sciences, from Brock University in Canada. “This new garnet-bearing rock type could give us clues to how Mars has changed throughout its history and new insights into the ancient environments that could have formed the garnet and related minerals.”

Mars Meteorite NWA 8171

The garnet fragments were discovered in a tiny Martian meteorite sample held in the Royal Ontario Museum’s collection, designated NWA 8171, discovered in northwest Africa. Kizovski led the team in analyzing the sample’s mineral and chemical composition after identifying it as a unique piece within the collection.

“This little section of the meteorite looked really interesting, and the chemistry was a bit odd,” Kizovski said. “At first, we assumed it was a mineral called pyroxene, which is very common, but then we decided to take a second look.”

The international effort brought in researchers from Italy’s University di Trieste and the UK’s Open University, utilizing the Royal Ontario Museum’s laser equipment and the University of Portsmouth’s Electron Microscopy and Microanalysis Unit.

Having never been observed in any previous Martian sample, the researchers were surprised to identify garnet in the meteorite’s composition. From their analysis of the sample’s chemistry and mineralogy, the researchers began to consider how the unexpected garnet could have formed.

“Garnet is a classic example of a mineral often found in metamorphic rocks on Earth,” Kizovski said. “The process of metamorphism transforms igneous or sedimentary rocks into a new form through exposure to extreme heat, high pressure, or hot fluids.”

“On Mars, the heat and pressure needed to produce garnet through metamorphism could have come from the impact of a meteorite hitting the surface of Mars, magma rising up into the Martian crust, or both,” Kizovski continued.

Explaining Martian Garnet

While garnet provided geologists with some data about how it formed, this is not like the point of origin stamped on a manufactured good. It is possible that the garnet was deposited on Mars during an earlier meteorite impact, only to later travel through the solar system again, or that it was created by a heretofore unknown magma source on Mars.

Only further analysis of the garnet’s isotopic signatures will allow the researchers to determine whether the mineral formed on Mars or elsewhere. Unfortunately, to do so, the team would have to destroy a portion of this rare and precious sample, which measures only 0.8 by 0.5 millimeters to begin with.

“Measuring oxygen isotopes from the garnet-bearing rock type itself would help to confirm if it is Martian in origin or from an exotic meteorite impactor,” Kizovski said.

“Isotopes are a collection of atoms with equal numbers of protons and electrons, but different numbers of neutrons,” she added, “which was avoided thus far due to its rarity, as it may be the only garnet-bearing Martian rock we have for study.”

A few members of the team are continuing their study of the sample by comparing their findings to Martian data collected by rovers and orbital platforms. Further insights, they hope, may help them discover more about how the garnet could have formed, and what its presence means for the deeper history of the Red Planet.

The paper, “Expanding Mars’ Lithologic Diversity: Discovery of a Garnet-Bearing Clast in NWA 8171,” appeared in Geochemical Perspectives Letters on June 16, 2026.

Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.

Combien de temps un volcan peut-il rester endormi avant de se réveiller ? L’étude d’un volcan grec montre que même plus de 100 000 ans de silence ne suffisent pas forcément à le déclarer éteint.

About 400 million years ago, the population of plants with vein systems for transferring water and nutrients, called vascular land plants, exploded. Soon thereafter, rocks from some continental magmas showed notable shifts in their chemical compositions. Geologists have suggested that these magma changes happened worldwide, but some argue that the data might be biased because some geographic regions have more samples to analyze than others. A new research team recently tested whether these magmatic changes occurred on a global scale, versus in isolated mountain belts or volcanic islands. 

Geologists use the chemistry of rocks formed from magma to understand a magma’s history. In particular, a mineral called zircon that forms from cooling magma preserves chemical clues about where the magma came from and what it interacted with. To test whether magma changes were global or local, the authors needed data ranging from the equator to the poles. Continents have shifted over the past 400 million years, so scientists use the latitude a rock had when it formed, called its paleolatitude, to compare samples from different parts of ancient Earth. To understand magma histories worldwide, the team used publicly available chemical data from zircons in magmatic rocks that formed across a wide spread of paleolatitudes.

Chemical elements with the same number of protons but different numbers of neutrons are called isotopes with different masses. To discern how plants influenced magma, the researchers analyzed 2 different isotope signals preserved in the zircons. The first isotope signal comes from the ratio of the heavy to light oxygen isotopes, which increases when sediment mixes into magma. Scientists refer to this value as δ¹⁸O, pronounced “delta 18-O.” 

The second isotope signal comes from the element hafnium, denoted Hf. Geologists use hafnium to estimate how long ago magmas melted and separated from the mantle. Zircon contains 2 Hf isotopes, one of which is stable and one of which is produced by radioactive decay. Because this decay happens over billions of years, the ratio between the 2 Hf isotopes over time shifts only slightly. Geologists express these tiny differences using a shorthand called εHf, pronounced “epsilon hafnium,” which shows how much a magma’s Hf signature has changed from Earth’s original mantle. Lower εHf values indicate magmas that incorporated older crustal rock, while higher εHf values reflect mantle sources.

The researchers found that δ¹⁸O values increased as εHf values decreased in these zircons. They concluded that this trend indicates increasing amounts of land-derived sediment in magmas, corresponding with the evolution of land plants. They suggested that land plants altered the ancient landscape, changing how sediments weathered and moved over land. 

To explore this pattern in detail, the team focused on the Andes Mountains, a region that preserves a long history of magmatic activity across a long span of space and time. Using a database, they accessed isotope data from zircon samples collected in the Andes Mountains by dozens of other research groups. These samples covered 32 degrees of modern latitude and 520 million years of Earth’s history, offering a broad window into how magma chemistry changed during that time.

They found that zircons older than 450 million years had no relationship between their εHf and δ¹⁸O values. However, in zircons younger than 450 million years, δ¹⁸O increased as εHf decreased. The researchers saw this pattern in magmas that formed along the edge of the continent, where one tectonic plate sinks below the other, called a subduction zone. They also saw this pattern in magmas that formed inland, away from the subduction zone, around 200 million years ago during the breakup of the supercontinent Pangaea.

 They found similar results in published zircon isotope data from igneous rocks in China, the Caribbean, Antarctica, Madagascar, and Tasmania. Zircons from each region showed the same relationship as zircons in the Andes. Since paleolatitude can also reflect ancient climate, the researchers compared the ratio of εHf and δ¹⁸O, written as εHf/δ¹⁸O, with paleolatitude to test whether ancient climate zones influenced magma chemistry. They found no link between paleolatitude and εHf/δ¹⁸O. 

With these results in mind, the researchers concluded that the relationship between εHf and δ¹⁸O shifted worldwide after vascular land plants evolved. They argued that as plants spread across the continents, their roots accelerated the breakdown of rocks. This accelerated weathering produced large amounts of sediment that washed into ocean basins and was eventually subducted into the mantle, forever changing the chemistry of magma formed there. They suggested that this chain of events illustrates how life on Earth’s surface can drive changes deep within the planet. 

The post Plants changed the chemistry of magmas appeared first on Sciworthy.

The continent of Africa is splitting into 2 tectonic plates in the middle of Ethiopia. In the recent past, geophysicists have improved their understanding of how tectonic plates like these separate. They’ve shown that continents begin to split apart as the crust and upper mantle, known as the lithosphere, crack and shift. Later, magma from deep within the Earth travels upward through these cracks to Earth’s surface, forming volcanoes. Therefore, scientists know that volcanoes form in areas of continental rifting, but not how quickly they form, which complicates efforts to assess volcanic hazards in rift zones.

Researchers led by Kevin Wong sought to answer this question by examining a mineral formed when magma cools, called olivine. They focused on 72 olivine crystals ranging in size from 1 to 4 millimeters (0.04 to 0.16 inches) from rocks collected at the Boku and Ziway volcanic fields in the Main Ethiopian Rift (MER) zone in Africa. They explained that the lithosphere in this area is still about 35 to 40 kilometers (21 to 25 miles) thick. This thick lithosphere suggests that the MER represents an intermediate stage of continental separation and offers a rare opportunity to study how tectonic stretching transitions into magmatic rifting in the process.

Wong and his team analyzed olivine because it’s one of the first minerals to crystallize from magma, and it continues to grow as the magma rises and cools. As magma rises, its composition changes, producing sharp chemical “zones” within the growing crystals, analogous to growth rings in trees. Changing temperatures and magma compositions cause different elements, like magnesium and iron, to diffuse into and out of the crystals at various rates during the magma’s ascent. So scientists can model these chemical zones and their boundaries in olivine crystals to determine how quickly the magma ascended from the upper mantle to erupt in the rift.

Wong and colleagues examined the olivine crystals from the MER volcanic fields using high-magnification imaging and chemical analyses, with an instrument known as an electron microprobe. Within each crystal, the team mapped 10 to 15 points spaced approximately 5 to 15 microns apart (about 10% of the thickness of a human hair) along a transect from the inner core to the outer rim, spanning its growth zones. 

They found 2 different populations of olivine crystals. The first consisted of normal-zoned crystals with magnesium-rich inner cores, and the second consisted of reverse-zoned crystals with lower magnesium cores. They explained that recently-formed magmas in the deep Earth contain higher amounts of the element magnesium relative to iron. The magnesium-rich zone has a sharp boundary with the magnesium-poor zone, but this boundary can get blurred when elements diffuse across it. Diffusion progressively smooths these crystal boundaries over time at known rates, so researchers can use their “blurryness” to extract information on how quickly the crystals equilibrated with the surrounding magma.

The researchers used numerical models to estimate how quickly magnesium and iron would diffuse across these chemical boundaries at different temperatures and surrounding magma chemistries. They compared thousands of simulated diffusion profiles to their measured olivine diffusion profiles. They used this iterative process to estimate that the crystals diffused, on average, for 40 and 17 days in the surrounding magma while ascending from the deep Earth to erupt at Boku and Ziway, respectively. They further tested these estimates using a growth-diffusion model that better represented natural crystal behavior. That model produced ascent times of about 27 days on average and better reproduced the crystal zoning patterns they observed.

Based on these models, the researchers concluded that intermediate-stage rifting events happen on unexpectedly short timescales. Magmas travel up to 40 kilometers (25 miles) from the deep Earth to the surface within, on average, a single calendar month, which is closer to human timescales than geologic timescales. They suggested that this rapid ascent is likely due to highly developed magmatic plumbing systems in the lithosphere that form before much lithospheric thinning. However, they noted that their results still suggest a wider range in ascension timescales than optimal for disaster mitigation and prediction. 

The post Magma rapidly rises to Earth’s surface as Africa splits in two appeared first on Sciworthy.