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One Billion Years Ago, Northern Minnesota Nearly Split Apart. Now, Two Companies Want to Mine the Aftermath.

EOS - Fri, 07/24/2026 - 10:45
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In April, President Donald Trump officially revoked a ban on mining that had protected more than 225,000 acres (91,054 hectares) of federal land in Minnesota’s Superior National Forest from mineral exploration and development.

“It’s official. The illegal mining ban put in place by former President Biden has been overturned indefinitely, ending a reckless policy that sidelined Minnesota’s miners and undermined our nation’s ability to source our own materials,” Rep. Pete Stauber (R-Minn.) said in a statement after the repeal.

The action stoked new public concern about two proposed mines near the Boundary Waters Canoe Area Wilderness, a remote, million-acre part of Superior National Forest peppered with interconnected lakes and streams. The NewRange Copper Nickel company’s NorthMet mine, a joint venture of PolyMet Mining Corporation and Teck Resources, would be located approximately 20 miles (32 kilometers) from Boundary Waters in the St. Louis River watershed, which drains into Lake Superior. The Twin Metals Minnesota mine, owned by the multinational mining company Antofagasta PLC, would be located even closer to Boundary Waters and within the Rainy River watershed, which ultimately drains into Lake of the Woods, a lake shared by the Canadian provinces of Ontario and Manitoba as well as Minnesota.

Trump’s repeal of the mining ban is just the latest step in a yearslong battle over the future of mining in northeastern Minnesota, which is a magnet for recreationists and mining companies alike because of a geologic past that created pristine lakes atop rich deposits of critical minerals.

A Rift in the Bedrock

The deposits targeted by NewRange and Twin Metals were formed as a result of a rifting event that took place in the Proterozoic eon, roughly a billion years ago, during which the North American continent was expanding and breaking apart, said Adam Simon, a geologist at the University of Michigan who studies mineral deposit formation. “You can literally think of it as a crack or unzipping of the crust.”

The rift ran from the northeastern corner of Lake Superior, through what is now southwestern Minnesota, and into current-day Iowa and Kansas. The separation of the continent reduced pressure on Earth’s interior, which allowed molten rock to rise from the mantle to just below the surface, and some even erupted at the surface as lava flows. Molten rock from Earth’s mantle contains high concentrations of metal sulfide minerals of interest to mining companies today, including copper, gold, silver, platinum, cobalt, nickel, and chromium.

The rifting event that formed the Duluth Complex stretched across the Great Lakes Region and created intrusions of magma (colored in red) rich in valuable minerals. Credit: Wikimedia Commons/USGS, Public Domain

This uplift of magma, followed by hundreds of millions of years of erosion from glaciers, eventually formed what geologists now know as the Duluth Complex, a roughly 100-mile-long (161-kilometer-long) area north of Duluth, Minn., rich in metal sulfides.

Sulfate Streams

Today, Minnesota is the “Land of 10,000 Lakes,” and many residents worry about the potential impacts of mining in the water-dominated landscape.

The main concern is sulfate, a by-product of the separation of metals from the sulfide minerals that encompass them. Mining companies typically try to contain sulfate by storing mining waste in underground pits and chemically treating water that has been used in mining processes, though mining is still a significant source of sulfate in natural waters.

Though sulfate itself is not harmful to wetland ecosystems, it can cause a range of ecological issues once it is chemically transformed, said Amy Myrbo, a geologist and environmental consultant in Minneapolis. Naturally occurring bacteria in lake bed mud transform sulfate to sulfide, which creates hydrogen sulfide, a substance harmful to plants, when dissolved. In Minnesota, wild rice is an edible wetland grass that serves as an important food source and sacred plant to Indigenous groups; it reacts poorly to water high in sulfide. Additionally, the process can make water browner, fuel algal blooms, and increase freshwater concentrations of a harmful, bioaccumulative form of mercury.

“It’s a really underappreciated contaminant.”

Sulfate is “a really underappreciated contaminant” in fresh water, she said.

Though mines themselves are prohibited within the Boundary Waters area, environmental advocates are concerned that sulfate pollution from mine waste could flow in the wilderness’s waterways. The Boundary Waters wilderness is particularly susceptible to the nutrient-increasing effects of sulfate because its lakes tend to have a high amount of organic matter in their sediments, Myrbo said. “If we get sulfate pollution there, it could really be a problem.”

Minnesota is the only state with a sulfate water quality standard, meant to protect waters used for wild rice production. That standard is one of the only measures keeping the two proposed mines from moving forward, as dozens of wild rice waters are located within watersheds where the two proposed mines would be located.

Controlling Mine Waste

Open-pit mines are common in Minnesota, where iron deposits can be found at very shallow depths. The NewRange mine, though not an iron mine, would also be open-pit.

The Twin Metals project, however, would be an underground mine. Mining this way “significantly reduces the surface environmental impact,” Simon said. “What they’re essentially doing is surgically removing the ore underground.”

Still, separating metals from sulfide minerals creates mining waste high in sulfate, a slurry-like substance called mine tailings. Twin Metals plans to control this waste by drying it and compacting it into a mound that will then be “reclaimed with native soil and vegetation,” a method called dry stacking.

NewRange Copper Nickel plans to store its tailings in an existing facility provided by a closed iron mine. The company states that its methods will “clean up water quality issues from legacy iron ore mining and processing, leading to net reductions in loading of mercury and sulfate in the St. Louis River.”

“If someone says they’re going to open a sulfide ore mine without environmental contamination, they’re saying, ‘We’re going to be the first ones to ever do this.’”

Environmental advocates doubt that either company has an infallible plan to contain its waste because of the track record of similar mining projects. For example, one report commissioned by Northeastern Minnesotans for Wilderness in 2025 reviewed eight hard-rock mines in the United States and found that all eight had degraded downstream water quality. A 2012 report from the environmental advocacy group Earthworks that reviewed 14 copper mines (representing 89% of U.S. copper production according to the most recent data at the time) found that each of the mines had experienced at least one spill or accidental release of mine waste.

“If someone says they’re going to open a sulfide ore mine without environmental contamination, they’re saying, ‘We’re going to be the first ones to ever do this,’” said Steve Emerman, a geologist and environmental consultant. Emerman advises the Friends of the Boundary Waters, an advocacy group, on the effects of mining on the wilderness area.

NewRange Copper Nickel and Twin Metals did not respond to requests for comment.

—Grace van Deelen (@gvd.bsky.social), Staff Writer

Citation: van Deelen, G. (2026), One billion years ago, northern Minnesota nearly split apart. Now, two companies want to mine the aftermath., Eos, 107, https://doi.org/10.1029/2026EO260239. Published on 24 July 2026. Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Statistical theory of electronic degrees of freedom in wave packet molecular dynamics

Physical Review E (Plasma physics) - Fri, 07/24/2026 - 10:00

Author(s): Daniel Plummer, Pontus Svensson, Wiktor Jasniak, Patrick Hollebon, Sam M. Vinko, and Gianluca Gregori

We derive statistical distributions for the degrees of freedom in wave packet molecular dynamics models. Specifically, a theory is developed for the width distributions of Gaussian wave packets in both isotropic and anisotropic formulations. The resulting distribution functions show good agreement w…


[Phys. Rev. E 114, 015219] Published Fri Jul 24, 2026

Inferring partial crystalline order in liquids from electrical resistivity

Physical Review E (Plasma physics) - Fri, 07/24/2026 - 10:00

Author(s): Nadine Wetta and Jean-Christophe Pain

This work investigates how locally persistent crystal-like ordering in liquids influences the Debye-Waller factor. We have developed a theoretical framework based on liquid-phonon theory which introduces a phonon relaxation time, expressed as the ratio of shear viscosity to infinite-frequency shear …


[Phys. Rev. E 114, 015220] Published Fri Jul 24, 2026

Study on Rayleigh Wave Dispersion and Attenuation in HTI Fractured Porous Media

Geophysical Journal International - Fri, 07/24/2026 - 00:00
SummaryIn near-surface porous media containing aligned fractures and fluids, the propagation of Rayleigh waves is influenced by both fracture geometry and wave-induced fluid flow. These processes introduce frequency-dependent dispersion and azimuthal anisotropy in both phase velocity and attenuation. To investigate these effects, this study applies Chapman-type fracture–pore effective medium theory to describe fluid-saturated fractured media as horizontally transversely isotropic (HTI) media with frequency-dependent complex stiffness. The complex dispersion relation of Rayleigh waves is obtained by combining this model with the Stroh formalism for HTI half-spaces. Numerical results show that Rayleigh-wave phase velocity exhibits clear frequency-dependent dispersion together with azimuthal anisotropy. The fast and slow propagation directions remain consistent with the orientation of the fracture strike. Rayleigh-wave attenuation exhibits a clear relaxation peak within the frequency band associated with wave-induced fluid flow and shows strong azimuthal variation. Parameter analysis further indicates that fracture density primarily controls the strength of azimuthal anisotropy, whereas porosity mainly affects the overall level of dispersion and attenuation. The relaxation time governs the frequency range over which dispersion and attenuation become significant. The combined frequency–azimuth variations of phase velocity and attenuation therefore provide potential constraints for estimating fracture–pore structures in fractured reservoirs using multi-frequency and multi-azimuth Rayleigh-wave observations.

AI unlocks Atlantic circulation insights from 20 years of ocean float data

Phys.org: Earth science - Thu, 07/23/2026 - 23:20
For more than 20 years, about 4,000 autonomous profiling floats have been drifting through the ocean. They form part of the international Argo program (Argo—global array of profiling floats). At regular intervals, they descend to a depth of 2,000 meters (6,600 feet) and, as they rise, measure parameters such as temperature, salinity and pressure. Once they reach the sea surface again, they transmit these data via satellite to the Argo network, which is available to researchers worldwide. Hardly any other observation system has transformed ocean research so profoundly in recent decades.

Global map reveals mining's uneven toll on forests and biodiversity

Phys.org: Earth science - Thu, 07/23/2026 - 21:40
A new study led by Japanese researchers from Tohoku University and the National Institute for Environmental Studies (NIES) reveals that some of the minerals most essential for green technologies may have a significant negative impact on biodiversity. Using remote sensing and machine learning, the scientists produced an unprecedented global map of mined commodities.

Colorado basins supplying 70% of Lake Powell's water face major midcentury shortages

Phys.org: Earth science - Thu, 07/23/2026 - 21:00
If the Colorado River Basin is the lifeblood of the American Southwest, keeping the region's agricultural, ecological and economic systems thriving, Colorado's West Slope River basins could be considered the heart. Together, they contribute about 70% of the water delivered to Lake Powell, the second-largest reservoir in the nation.

Drought, water shortages and crop failures: How does the medieval warm period compare with today?

Phys.org: Earth science - Thu, 07/23/2026 - 15:40
A heat wave lasting four months, followed by water shortages and crop failures. This is England in the 13th century, not the 21st. What is often called the Medieval Warm Period saw elevated temperatures in many parts of the world between the 10th and 13th centuries.

Trump’s Science Adviser Wants to Overhaul “Increasingly Calcified” U.S. Science Enterprise While Science Funding Lags

EOS - Thu, 07/23/2026 - 15:05
body {background-color: #D2D1D5;} Research & Developments is a blog for brief updates that provide context for the flurry of news regarding law and policy changes that impact science and scientists today.

23 July: This article was updated to include comments from Jennifer Jones and Colette Delawalla.

A report released this week directs the U.S. government to spark a “new golden age” of science by ushering funds toward artificial intelligence, fostering closer relationships with private industry, and dismantling and rebuilding the federal science funding process.

The report was written by Michael Kratsios, director of the White House Office of Science and Technology Policy. He outlined his recommendations to Congress at a hearing of the House Committee on Science, Space, and Technology on 22 July. 

Kratsios intended the report to emulate a letter written to President Franklin D. Roosevelt by Vannevar Bush in 1945, called Science, the Endless Frontier, which set the foundation for the current U.S. federal science process in which federal funds support university research. “As we celebrate the United States’ 250th anniversary, we have the responsibility to renew our foundations once more,” he wrote.

Kratsios listed four goals to guide this approach to U.S. science: to “prioritize the individual scientist over legacy institutions,” to “fundamentally change how research dollars are allocated, distributed, and assessed,” to “set clear scientific goals and build the industrial muscle to translate scientific discovery into technological strength,” and to “prepare our research enterprise for the AI revolution.”

“If you think about this report in the context of everything else this administration has done, it really is about weakening independence, weakening accountability, [and removing] scientific integrity protections in favor of empowering political appointees,” said Jennifer Jones, director of the Center for Science and Democracy at the Union of Concerned Scientists.

Science-A-New-Golden-Age_EosDownload

The report recommends a handful of federal priorities to achieve these goals, including the Genesis Mission, a “national effort to harness AI for scientific discovery at a scale no other nation can match” led by the Department of Energy (DOE).

At the 22 July hearing, Kratsios said the Genesis Mission “is the crown jewel of American AI for science” and announced that federal agencies have committed more than $5 billion to the project. So far, 278 awards have been made, the largest being a three-year, $60 million grant for a project that will “help deliver nuclear facilities faster and safer” with the use of AI, according to the DOE. 

“There’s no mention of scientific integrity, no mention of protections for independence, it’s just the opposite.”

“There are some examples in STEM where AI is valuable,” such as increasing power in computational modeling or identifying new Earth-like planets at scale, for example, wrote Colette Delawalla, founder of science advocacy group Stand Up for Science, in an email. “But AI will never replace curiosity-driven scientific advancement,” she wrote. 

Some scientists viewed the report as a way for the government to justify steering research funds toward private industry and increasing political interference in science. “I think they’re trying to turn it into a venture capital model,” Jeremy M. Berg, a computational biologist and former director of the National Institute of General Medical Sciences at the National Institutes of Health, told The New York Times

“Under the hood,” the report is a “vision for faster technology development and commercialization while underinvesting in the fundamental research, expert peer review, and scientific workforce that make those advances possible,” Keivan Stassun, an astrophysicist and member of the National Science Board prior to its dissolution by the Trump administration, told Science.

What’s interesting about the report, Jones said, is what it doesn’t mention. “There’s no mention of scientific integrity, no mention of protections for independence, it’s just the opposite,” she said. “There are no clear systems of accountability” explained in the report, and its suggestion to funnel funds to individual researchers rather than institutions such as universities also means more research could occur outside of universities’ established and robust systems of accountability, she added.

The recommendations in the document largely align with recommendations made by former National Academy of Sciences president Marcia McNutt in June. In the annual president’s address, McNutt encouraged the scientific community to “better understand the needs of industry” and embrace the use of AI to increase research efficiency. 

At the hearing, however, Kratsios agreed with Rep. Brian Babin (R-TX), chair of the committee, that the National Academies of Science, Engineering, and Medicine required more federal oversight, especially in light of its recent report on climate attribution science that Babin said raised “transparency concerns.” Kratsios said he looked forward to working with Congress to codify the recommendations made in the “new golden age” report.

Funding the Golden Age

The vision the report presents is accompanied by recommendations from Kratsios and Russell Vought, director of the Office of Management and Budget, for the FY 2028 budget. These recommendations include prioritizing funding for physical sciences, including quantum physics, chemistry and materials sciences, mathematics and computer sciences, engineering, and biological sciences. 

For FY 2028, “agencies should align their R&D investments, where appropriate, with the Administration’s national missions,” the report states, listing those “national missions” as AI, quantum computing, fusion power, the construction of a lunar base and return of humans to the Moon, autonomous robotics, and semiconductor technology. 

 
Related

At the 22 July hearing, Democrats argued that the Trump administration’s actions have worked against the stated goals of Kratsios’s report. “Big new initiatives and promises mean nothing when agencies act capriciously, canceling grants midway, delaying awards for months, even after they’ve been selected through the rigorous merit review process, and blacklisting educational and research institutions,” said Rep. Zoe Lofgren (D-CA).

The report did not mention the Trump administration’s proposed FY 2027 budget, which, if finalized, would reduce the National Science Foundation’s budget by 53%, the U.S. Geological Survey’s budget by 37%, the NASA science budget by 42%, and NOAA’s budget by 28%.

“I anticipate the report will be used as the rationale for making further cuts in the budgets and staffing of federal research agencies while limiting their authority and accountability to the American people,” Neal Lane, former director of the NSF, told Science

The report also did not mention recent sweeping cuts to the NSF’s FY 2026 budget, the fact that the NSF currently has no director, or a June proposal from the Office of Management and Budget that, if finalized, would give political appointees final approval power for scientific grants.

—Grace van Deelen (@gvd.bsky.social), Staff Writer

These updates are made possible through information from the scientific community. Do you have a story about how changes in law or policy are affecting scientists or research? Send us a tip at eos@agu.org. Text © 2026. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Predicting where wildfire smoke will go next

Phys.org: Earth science - Thu, 07/23/2026 - 14:00
In recent summers, wildfire smoke has been inescapable across Wisconsin, drifting south from Canada and leading to long stretches of poor air quality. Whether that smoke clears or lingers is often influenced in part by the atmospheric boundary layer—the lowest part of the atmosphere, where airborne particles mix and move.

Small Faults Add to Seattle’s Quake Story

EOS - Thu, 07/23/2026 - 13:09

The winter earthquake of 923 or early 924 CE remains the benchmark event in the Seattle Fault Zone. It lifted shorelines around Puget Sound and gave geologists one of the most decisive records of the fault’s power.

But that shoreline-lifting earthquake is only part of the zone’s history. A recent Geological Society of America Bulletin study led by Stephen J. Angster, a geologist with the U.S. Geological Survey, looks past the most famous Seattle fault earthquake to examine evidence of earthquakes on lesser-known secondary faults.

At Lytle Beach on Bainbridge Island and at Vasa Park near Bellevue, subtle landforms and trench records suggest evidence of smaller ruptures has been preserved in the landscape but not fully recognized.

At Lytle Beach, the first clue was a small, raised surface. Angster described the “localized uplifted terrace” as “the first feature we saw that drew our eye to that area.” Similar features had already helped geologists read other secondary faults in the Seattle Fault Zone.

For instance, Angster said the Toe Jam Hill fault became one of the better-known examples when lidar helped reveal its scarp through dense vegetation. Later work found smaller uplifted terraces near similar secondary structures, which Angster said may indicate separate earthquake events focused on smaller faults rather than the larger regional rupture.

However, Lytle Beach stood out in a different way, as its fault dips south, in contrast to the zone’s better-known secondary faults, which dip north.

Faults Hidden in the Fold

Finding the localized uplifted terrace was only the beginning for Angster, who used lidar to uncover scarps and lineaments through the region’s forest cover.

His team also utilized ground-based magnetic transects across the Lytle Beach fault to look for changes that may reveal displacement beneath the surface. In addition, they gained a more direct view of disturbed sediments by excavating the Rose Hip trench across the newly identified Lytle Beach scarp and analyzing evidence from the earlier Vasa Park trench.

In the Rose Hip trench at Lytle Beach, Angster said the team found glacial deposits dating to roughly 15,000 years ago. Above them were lake sediments left behind as ice retreated. The trench also preserved an old layer of soil that formed after the lake dried. “That whole package was folded,” he said. “The only way you could fold those is mostly by a tectonic fault.”

A regional map of the Seattle Fault Zone shows the Lytle Beach and Vasa Park fault scarps, along with the uplifted shore platform associated with the 923 CE earthquake. A new study used mapping, geophysics, trenching, and dating methods to investigate secondary faults within the broader fault zone. Credit: Angster et al., 2026, https://doi.org/10.1130/B38333.1, CC-BY-4.0

The trench record showed evidence of two surface-rupturing earthquakes on the Lytle Beach fault. The older event occurred between 11,240 and 10,430 calibrated years before present, whereas the younger event occurred after 1663 CE, likely in the early nineteenth century. (“Calibrated years before present” refers to dates arrived at via radiocarbon dating, relative to the year 1950 as the “present.”)

“I thought the trenching on Lytle Beach was surprising, that we found two events, because it was such a relatively subtle feature that wasn’t really identified before,” Angster said.

At Vasa Park, the team found evidence of one past earthquake that occurred sometime between 11,380 and 7,400 calibrated years before present. That range overlaps with the older Lytle Beach event and raises the possibility of a longer rupture along the Blakely Harbor fault. However, the evidence in Angster’s study better supports separate ruptures on the two secondary faults.

A Longer Record of Smaller Ruptures

Harold Tobin, an earthquake scientist at the University of Washington who was not involved in the study, called the work “exciting new research.”

He said the study shows there is “room to accommodate smaller earthquakes” that do not reshape shorelines like the 923 or 924 event but are “still big enough to be damaging earthquakes.” The Angster paper, he said, examines “additional earthquakes not accounted for in the shoreline uplift record centered on the 923 or 924 event. These smaller earthquakes may have happened more recently or more often.”

“Subtle features, relatively small or fault traces that we might have ignored before, can be an important part of the story.”

For Tobin, the value also extends beyond Puget Sound. The study “shines a light for other people working in cities and urbanized settings,” he said, because it shows that “subtle features, relatively small or fault traces that we might have ignored before, can be an important part of the story.”

By comparing the dated events at Lytle Beach, Vasa Park, and other secondary faults, the authors estimated that these faults may have ruptured roughly every few hundred years during the late Holocene. Angster cautioned that it’s not quite clockwork. “The secondary faults appear, especially within the last 2,500 years, to rupture more frequently, and that’s where that 350-year interval comes from,” he said. But the estimate rests on a limited record.

Though the work doesn’t forecast the next earthquake, it gives scientists more of the past to weigh as they assess the Puget Lowland. Tobin said the paper “certainly beg[s] more research” because the Seattle Fault Zone contains many strands that still need to be studied. Earthquake hazards should remain “something real” for the public and civil planners.

“We don’t know when they are going to come,” Tobin said. “Obviously, we can go decades without any significant earthquakes, as we have since 2001. But when we least expect it, one will happen, and we just have to be prepared.”

Angster framed the findings more conservatively: “This study doesn’t really change the hazard with the Seattle Fault. It just provides more insight into how it behaves.”

—Jason Collins, Science Writer

Citation: Collins, J. (2026), Small faults add to Seattle’s quake story, Eos, 107, https://doi.org/10.1029/2026EO260238. Published on 23 July 2026. Text © 2026. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.

Variational approach to Yukawa fluids. I. Thermodynamics

Physical Review E (Plasma physics) - Thu, 07/23/2026 - 10:00

Author(s): S. A. Khrapak and A. G. Khrapak

The excess energy, entropy, and pressure of a strongly coupled Yukawa fluid are calculated from the variational approach using the fluid of hard spheres as a reference system. As in the case of the one-component plasma, the Percus-Yevick virial entropy is appropriate for such calculations and delive…


[Phys. Rev. E 114, 015216] Published Thu Jul 23, 2026

Variational approach to Yukawa fluids. II. Instantaneous elastic moduli and sound velocities

Physical Review E (Plasma physics) - Thu, 07/23/2026 - 10:00

Author(s): S. A. Khrapak and A. G. Khrapak

The variational approach based on the Bogoliubov inequality using the fluid of hard spheres as a reference system is implemented to evaluate instantaneous shear, bulk, and longitudinal elastic moduli, as well as related sound velocities of Yukawa fluids. The remarkable accuracy of this method is doc…


[Phys. Rev. E 114, 015217] Published Thu Jul 23, 2026

Direct observations of pass-through and coalescence in collisions between electron phase-space holes

Physical Review E (Plasma physics) - Thu, 07/23/2026 - 10:00

Author(s): Yue Dong, Zhigang Yuan, Shiyong Huang, Xiongdong Yu, Zuxiang Xue, Honghong Wu, Dedong Wang, C. J. Pollock, R. B. Torbert, and J. L. Burch

Electron holes are Debye-scale kinetic structures that mediate particle trapping, field-aligned electric fields, and energy conversion in collisionless plasmas. How such coherent structures interact with one another, however, has remained difficult to resolve in situ. Using four-spacecraft Magnetosp…


[Phys. Rev. E 114, 015218] Published Thu Jul 23, 2026

Transient striations during gas breakdown under radio-frequency excitation

Physical Review E (Plasma physics) - Thu, 07/23/2026 - 10:00

Author(s): De-Hua Shi, Xiao-Kun Wang, De-Qi Wen, and Yong-Xin Liu

While investigating radio-frequency gas breakdown, the authors experimentally observed and simulated a novel, time-dependent striated optical emission structure. The study reveals that these striking patterns are driven by differing electron-ion mobilities and locally amplified ionization, which are ultimately suppressed as the electric field becomes screened.

#AdvancingField


[Phys. Rev. E 114, L013201] Published Thu Jul 23, 2026

Platform–corrected analyses of near-bottom magnetic data acquired by autonomous underwater vehicles

Geophysical Journal International - Thu, 07/23/2026 - 00:00
SummaryAutonomous underwater vehicles (AUVs) provide high-resolution magnetic measurements essential for investigating crustal accretion, tectonic segmentation, and hydrothermal processes at mid-ocean ridges. However, raw magnetometer measurements are strongly influenced by platform-induced magnetic fields, attitude-dependent biases, and navigation uncertainties that must be corrected to recover geophysically meaningful anomaly fields. We apply a procedure to measurements from AUVs which includes platform independent scalar calibration, transformation into geographic reference frames, spin-based removal of permanent and induced vehicle magnetization, and computation of magnetic anomalies relative to the International Geomagnetic Reference Field. The framework also incorporates a two-dimensional spectral upward continuation to reconcile altitude variations, thereby recovering anomalies at a uniform reference level. Application of this system to AUV datasets from the East Pacific Rise and Mid-Atlantic Ridge demonstrates effective suppression of platform biases, improved crossover consistency, and the generation of internally coherent geomagnetic anomaly fields suitable for subsequent analysis and mapping.

Deep crustal structure and rifting-spreading evolution of the southwest subbasin, South China Sea

Geophysical Journal International - Thu, 07/23/2026 - 00:00
SummaryThe Southwest Subbasin (SWSB) of the South China Sea represents a young oceanic basin formed by continental rifting and subsequent seafloor spreading between ∼23.6 and 16 Ma. Yet the deep crustal structures of its continental margins and the oceanic crustal accretion processes remain poorly understood. This study presents integrated two-dimensional seismic and density models along the OBS2020-3 profile, which traverses the continental margins and oceanic basin, using seismic refraction, multichannel seismic reflection, and free-air gravity data. Our results reveal prominent intra-crustal reflectors at ∼11.5 km depth beneath the northwestern continental margin, which we interpret as the brittle-ductile transition marking depth-dependent extension during rifting, without any evidence of high-velocity lower crust layers. Within the oceanic basin, the thin magmatic crust overlying serpentinized mantle suggests reduced magmatic supply during its opening. Combined with published seismic profiles crossing the ridge axis to the northeast and southwest, our results reveal a systematic southwestward decrease in crustal thickness in the ridge-parallel direction, suggesting a progressive reduction in melt supply toward the southwestern termination of the SWSB. The ridge axis (Longmen Seamount) is characterized by pronounced crustal low-velocity anomalies accompanied by apparent crustal thickening. We interpret that these features resulted from enhanced porosity and mantle serpentinization, both facilitated by extensive faulting during the final, tectonically dominated spreading stage. Together, these findings provide new constraints on continental extension along the northwestern margin of the SWSB and oceanic crustal accretion within the basin, and highlight comparable fault-controlled processes in other marginal seas.

A longer, hotter reality surrounds marine heat waves, research reveals

Phys.org: Earth science - Wed, 07/22/2026 - 23:20
Anyone who has boiled a pot of water understands that it takes both time and energy to raise the temperature, so it may come as a surprise to learn that scientists have long treated marine heat waves (MHWs) as isolated events. New research led by William & Mary's VIMS & Batten School is challenging that narrative by providing a framework to characterize an ecosystem's cumulative heat exposure from MHWs and the extended periods of warm water that precede and follow them.

Shifting weather patterns drive 55% of Europe's summer drought trend, study finds

Phys.org: Earth science - Wed, 07/22/2026 - 21:00
In a new study, researchers at Leipzig University have identified a major cause of the unusually severe summer soil drying and rising temperatures across Europe. They found that much of the trend can be attributed to changes in atmospheric circulation patterns—that is, shifts in the weather regimes that typically occur over Europe. These changes account for around 55% of the observed summer drought trend. Specifically, more frequent and persistent high-pressure systems have brought drier conditions and reduced rainfall.

Q&A: Listening with light—an innovative new technology for studying the seafloor

Phys.org: Earth science - Wed, 07/22/2026 - 19:40
The seafloor plays an important ecological and societal role. Understanding the processes that shape this environment will help guide conservation policy and decision-making about underwater infrastructure and geohazards.

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