How the geographic south and north poles wander

Amazing stuff!

"... as mass shifts deep within our planet, its geographic poles—the tippy top and bottom of Earth, based on its rotation—can also move. Now, researchers have looked back in time to find episodes of the phenomenon, called true polar wander—and they’re more dramatic than we had previously realized.

As plate tectonics and the natural churning of the mantle shuffle around matter inside Earth, the planet’s spin changes slightly. To get back on balance, Earth’s interior slides around on the dense molten core, causing the geographic poles to shift as well. To look for such periods in the geologic past, researchers analyzed records of flooding and drying over the past 320 million years.

They sought a four-leaf clover pattern characteristic only of true polar wander, where opposing halves of the northern and southern hemispheres drown and dry out—a consequence of the continents shifting in and out of the equatorial region, where Earth’s spin makes water bulge.

The clover pattern arose roughly 20, 90, 140, and 190 million years ago. Today, true polar wander occurs at about 10 centimeters per year—too minimal to notice. But when it accelerates, major changes to Earth’s biosphere and climate can result.

 ..."

"On Earth, everything is moving. The planet spins, the tectonic plates shift and the spin axis wobbles as do the magnetic poles, which makes determining how things move a rather tricky proposition. ...

Since the spin axis of the Earth usually overlaps with the magnetic pole, at least in recent geologic history, researchers can use the magnetic pole as a proxy for the spin axis. ...

Our results indicate that around 56-48 million years ago, the entire solid Earth reoriented relative to the spin axis, which gave us the jump found in the paleomagnetic record.” ..."

From the editor's summary and abstract (1):

"Editor’s summary

True polar wander (TPW), which occurs when the solid outer Earth shifts relative to its spin axis, is difficult to detect with standard approaches using paleomagnetic measurements. Domeier et al. used a different strategy to detect TPW in the Mesozoic Era using reconstructions of sea level as a proxy.

They found a robust quadrupolar pattern that reflects global sea-level fluctuations associated with relative changes in centrifugal potential that occurred due to rapid TPW. This demonstrates that coupling in Earth’s rotational dynamics, mantle processes, and surface environments can be highly episodic. ...

Abstract

True polar wander (TPW) is presently occurring at a rate of ~10 centimeters per year, exceeding the mean rate of differential plate motion. Whether this rate is transient and negligible on geological timescales or whether Earth has experienced rapid TPW lasting millions of years is unclear.

Paleomagnetic evidence has been used to propose fast episodes of TPW, but limitations of the paleomagnetic record have precluded definitive results. Rapid TPW will induce global sea level fluctuations associated with relative changes in centrifugal potential, offering an independent test. We evaluated this prediction using continental flooding reconstructions and identified multiple robust quadrupolar patterns since 320 million years ago, confirming that protracted rapid TPW has occurred on Earth and that couplings among Earth’s rotational dynamics, mantle processes, and surface environments can be strongly episodic."

From the abstract (2):

"It is well established that the Hawaiian hotspot moved southward relative to the spin axis in Paleogene time.

Two contrasting prior explanations are:
(a) reorientation of the solid Earth relative to the spin axis (i.e., true polar wander (TPW)), and
(b) independent southward motion of the Hawaiian hotspot through the mantle. Here we distinguish between these hypotheses by determining a new chron C24r (56 Ma) Pacific plate paleomagnetic pole from skewness of marine magnetic anomalies. This extends a set of Pacific plate spin-axis locations for which the repeatability is 2–5.5 times better than for coeval continental paleomagnetic poles. The new pole extends the northward progression of the prior 73–58 Ma Pacific plate apparent polar wander (APW) track such that it overlaps the southern end of the 48–12 Ma track.

From 56 to 48 Ma (between two intervals of true polar stillstand) either the Pacific plate moved rapidly southward relative to the mantle (with even faster southward motion of Pacific hotspots with both Hawaii and Louisville hotspots moving south) or TPW occurred.

The reconstructed plate geometry and relative plate motions are inconsistent with ancient plate driving forces having caused the observed southward motion relative to the spin axis.

The best explanation is an ∼6°–7° episode of TPW, but motion between hotspots and some southward motion of all Pacific hotspots through the mantle may also have occurred. The hypothesized TPW episode occurred near the end of the Early Eocene Climate Optimum and the onset of Cenozoic cooling."

ScienceAdviser

Quadrupolar sea level fluctuations reveal episodes of rapid polar wander (1, no public access)

Rice researchers find evidence of true polar wander (original news release) "Anomalous movement in Pacific plate record may be explained by movement of entire solid Earth relative to its spin axis"

Changes in Latitude of Pacific Hotspots From ∼56 Ma to ∼48 Ma Inferred From Pacific Plate Apparent Polar Wander Before and After Chron C24r: Implications for True Polar Wander (2, no public access)

Source

25,000 Rock Samples Reveal Gondwana's Scale, the ancient supercontinent was far larger than previously believed

Amazing stuff!

25,000 Rock Samples Reveal Gondwana's Scale | WION News - YouTube

Was Gondwana actually a larger and a true supercontinent? Call it Greater Gondwana

Amazing stuff! What a jigsaw puzzle!

"... Now, Gondwana is posing a new challenge. By studying the age of basement granites known to have existed near the continent’s edge, a team of geologists has found that Gondwana was much bigger than previously thought, encompassing up to 80% of the continental crust at the time, and adding some 127 million square kilometers to its extent. Such size, they suggest, makes it a true supercontinent, nearly on par with Pangea, which formed several hundred million years later.

The finding, if it holds up, challenges the notion of supercontinent cycles—the idea that the continents break apart and smoosh together, driven by shifts in the mantle, in regular cycles of 500 million years or so. ..."

"... Geologists have long gone back and forth on the status of Gondwana, which was discovered more than 100 years ago when common plant fossils were found on widely separated continents.
In 2012, Joseph Meert, a paleogeographer at the University of Florida, concluded supercontinents should at a minimum encompass 75% of all known continental crust. At the time, Gondwana was mostly thought to comprise present-day India, Australia, Africa, Antarctica, and South America—64% of known land. The 75% threshold was always arbitrary ...

But since then, Gondwana’s size has grown, as geologists added continental fragments in the eastern United States, southern Europe, Turkey, Iran, and Pakistan. But other fragments that existed at the time, including much of China, have not traditionally been assigned to Gondwana. Magnetic signals preserved in rocks that can help determine where ancient crust was located are difficult to interpret during this period. The jigsaw puzzle is further complicated by the repeated opening and closing of narrow oceans in East Asia at the time. ..."

From the abstract:

"Profound global biogeochemical shifts marked the Ediacaran-Cambrian transition [550–500 million years (Ma)], a phenomenon often ascribed to the dynamics of supercontinent cycles.

However, Gondwana is frequently denied supercontinent status due to its perceived spatial deficit (∼64% of continental landmass). Leveraging continental-scale Nd isotopic mapping based on a vast database of 25,346 felsic-intermediate igneous rocks, we reveal extensive buried Precambrian terranes beneath Phanerozoic orogens in Asia, Europe, and North America.

Our results expand Gondwana’s reconstructed area to ∼80% of the global landmass, firmly establishing its identity as a true supercontinent—termed “Greater Gondwana.” We propose that the assembly and peripheral subduction of this “Greater Gondwana” played a pivotal role in driving the geodynamic and environmental perturbations that culminated in the Cambrian metazoan radiation."

ScienceAdviser

Pangaea’s ‘little brother’ may finally qualify as a supercontinent

Buried fragments reveal a “Greater Gondwana” supercontinent (open access)

Fig. 1. Continental-scale Nd isotopic (TDM2) map of southwestern Asia, central Europe, and southeastern North America (encompassing peri-Gondwana terranes and orogens).

Fig. 4. Reconstruction of Greater Gondwana at ca. 500 Ma or at 550 to 500 Ma compared with conventional paleogeographic interpretations (inset).

Recent research into the deep underground geology of China

Amazing stuff!

Unfortunately, the articles do not contain any charts nor maps!

"... in southwestern China, scientists recently set off 500 kilograms of dynamite to send seismic waves deep into the crust. The experiment is part of SinoProbe II, a $1 billion effort to map China’s deep geology at unprecedented scale.

Early results from the seismic survey have  revealed a structure that researchers interpret as the buried boundary between two ancient continental blocks. If confirmed, the finding could help resolve competing ideas about how South China formed hundreds of millions of years ago. ...

In Tibet, dense networks of seismometers will probe how the Indian plate is being torn and deformed beneath the plateau.

And in northern China, researchers are looking for remnants of a vanished continental root. The work could also guide the search for critical minerals and other resources. ..."

ScienceAdviser

With billion-dollar project, China maps scars of its geological past

Nepal: Was it an unusual glacier collapse or frequently occuring massive bedrock failure/glacier collapse?

Recommendable, but again too lengthy an article as is typical for Climate Discussion Nexus!

I just blogged here about the potential culpability of China, because it did not warn or prevent this natural catastrophe.

How much of this catastrophe is due to manmade changes to the environment like construction, bulldozing of mountains etc.

Then there is the growth of population in Nepal from about 8 million to about 30 million since 1950. (Google Search)

"... it was all very predictable, yet they did not predict it, nor did they take even a fraction of the money given by the west to Nepal ... “woke green nonsense” and use it to install inexpensive sensors and sirens that could have given the unfortunate people downstream critical time to escape. ...

“Data shows that glacial failures – the scientific term for a category of events that includes ice avalanches, glacier detachments and rock-ice avalanches – have happened dozens of times since 1900 in the China-Nepal border region that was the site of this week’s devastation.” ..."

"Highlights

• Nepal flood, caused by a massive bedrock failure beneath a glacier, has been elucidated by recent satellite imagery
• Geomorphologists ... revealed that a significant portion of the mountainside bedrock collapsed
• This catastrophic event sent ice and boulders crashing into the valley, burying villages and causing the Trishuli River to surge

..."

Ghouls descend on Nepal - Climate Discussion Nexus

New satellite images reveal surprise cause of Nepal floods: ‘Not just a glacier’ "The Nepal flood cause was a massive bedrock failure that took a glacier with it, according to new satellite imagery analysis"

Thunderquakes to image the Earth's subsurface

Amazing stuff!

"... the powerful acoustic waves from thunder can ripple the Earth, the resulting seismic signals have long been too difficult to parse. Now, researchers have turned the so-called “thunderquakes” into a useful tool for probing inside Earth.

To interpret thunderquakes, researchers turned to a technique called distributed acoustic sensing. It involved turning a 4-kilometer-long fiber-optic cable, more commonly used for internet and phone services, into a string of more than 2100 sensors that measured vibrations in the ground. In two years, the team identified 458 high-quality thunderquakes.

Since seismic waves travel at different speeds at different depths, the team used the thunderquakes to map the ground below, down as deep as 100 meters. In Pennsylvania, where the cable is located, researchers spotted weak zones and areas where the ground is sinking, both geological features that can cause sinkholes or groundwater contamination if left unaddressed. ..."

"... Using existing fiber-optic telecommunication cables buried just a few feet below the ground under Penn State’s University Park campus, the researchers developed a new way to use distributed acoustic sensing technology, or DAS, to better understand how atmospheric acoustic waves transfer energy into the ground. They also demonstrated how this coupling can be used in seismic imaging. ..."

From the abstract:

"Thunder generates atmospheric acoustic waves that couple into the ground, producing seismic signals called “thunderquakes.” Although widely observed, this atmosphere-solid Earth conversion has rarely been exploited for imaging because the coupled wavefield is complex and its governing physics are poorly constrained.

Here, we show that thunderquakes recorded by preexisting telecommunication fiber-optic cables using distributed acoustic sensing (DAS) contain coherent air-coupled Rayleigh waves that can serve as seismic energy sources for near-surface tomography.

We validate this mechanism using three-dimensional spectral-element simulations and dispersion modeling of thunderquakes.

We analyze 2.5 years of continuous DAS data and a catalog of 458 high-fidelity thunderquakes validated by lightning records.

Cross-correlation virtual-source interferometry and stacking yield dispersed surface waves from which we invert shear-wave velocity structure to ∼100-meter-depth beneath an urban karst setting. The resulting tomographic image reveals several previously undetected weak zones, some coinciding with surface deformation measured by Interferometric Synthetic Aperture Radar.

The tomographic results are further validated by independent borehole logs and engineering surveys.

Our results establish that thunder energy can be converted into dispersive seismic wavefields in the solid Earth and that thunderquakes can act as novel, meteorologically driven sources for seismic imaging in regions with limited access to traditional seismic sources."

ScienceAdviser

Thunderquakes: A new way to image the Earth’s subsurface (original news release) "Thunderstorms detected by underground fiber-optic cables can be a source for seismic imaging, especially in places where earthquakes are uncommon, researchers report"

Imaging Earth’s subsurface with thunderstorm-generated seismic waves (open access)

Fig. 1. Thunderquake raypath diagram.

Fig. 6. Subsurface tomography results.

Sedimentary rocks from east India point to early traces of life about 3.5 billion years ago

Amazing stuff! Out of Africa or out of India?

It appears the German University of Technology in Oman has done similar research in Singhbhum Craton, India at least since March 2024, see Sedimentology and geochronology of Mesoarchean siliciclastic successions of the Singhbhum Craton, India and their implications

"Early in Earth’s history, the planet was covered in oceans. But the real hotspots were hydrothermal environments, where volcanic and tectonic activity provided the energy and nutrients needed for life to develop.

Over 3 billion years later, sedimentary rock formations known as cherts preserve traces of these ancient landscapes. Now, a new study presents evidence that they contain traces of life, too. ...

The findings provide the earliest evidence of life’s carbon signatures from a directly dated rock sample, reinforcing previous estimates of when life began."

From the significance and abstract:

"Significance

Kerogen, insoluble organic matter preserved in sediments, represents some of the earliest known terrestrial biosignatures which have provided important insights into the origin of life and planetary habitability.

Direct dating of these materials can be complicated by the lack of suitable geochronometers, instead relying on indirect constraints from, for example, the age of cross cutting lithologies.

Here, we report a 3.5-billion-year-old carbonaceous chert from eastern India containing what are interpreted to be contemporaneous tuffaceous zircons.

The chert exhibits micron-scale alternating layers of carbonaceous and siliceous materials. 

δ13C isotope data of carbonaceous matter (CM) together with stratigraphic relationships indicate a biogenic origin of the kerogen marking this to our knowledge the oldest directly dated rock with a confirmed biosignature.

Abstract

Zircons interpreted to be of syn-volcanic origin recovered from the lower greenschist “black and white banded” Bhitardari chert, Eastern Iron Ore greenstone belt, Singhbhum craton, India, yield a 207Pb/206Pb zircon age of 3497 ± 5 Ma (n = 4; MSWD = 1.2).

This chert contains abundant carbonaceous matter (CM) that occurs in two textural modes:
1) ultrafine laminae distributed within the matrix and
2) graphite flakes in late quartz veins.

Bulk δ13CCM of both modes in the Bhitardari chert yield a value of −30.9‰, which we interpret as reflecting a biogenic origin.

This represents the documentation of a directly dated, CM-bearing, Paleoarchean rock with δ13CCM diagnostic of biologic activity.

The observed isotopic compositions are consistent with the rise of relatively sophisticated metabolic mechanisms (e.g., Calvin cycle) by 3.5 Ga."

ScienceAdviser

Direct dating of 3.5 Ga biogenic carbon in a microbial mat remnant, Singhbhum Craton, India (no public access)

Direct dating of 3.5 Ga biogenic carbon in a microbial mat remnant, Singhbhum Craton, India (This repository appears to provide access to the research article PDF file)

Planet Venus may be geologically active

Amazing stuff! This was discovered on NASA images from the 1990s? What took so long?

Do we need a new Venus mission?

"... New research shows our planetary neighbor may be less dormant than thought. Scientists reanalyzed rift valleys on Venus’s surface, which are low-lying regions formed as the crust pulls apart or due to volcanic activity. On Venus, rift valleys can span as long as 10,000 kilometers ...

High-resolution computer models of the underlying geological processes revealed that broad ridges called rift flanks form at the valleys’ edges when they are either young or still forming. Soon after, the rift flanks widen and flatten as Venus’s crust relaxes. When the researchers looked at images of the venusian surface taken by NASA’s Magellan spacecraft in the 1990s, wide, high flanks were visible. The features indicate that the surface was active somewhat recently—and the world is far from dead. ..."

"In brief

• ETH researchers have developed innovative computer models to study the rift valley systems on Venus.
• The simulations indicate that recently formed rift valleys feature high, broad flanks, whereas older valleys tend to subside and are less elevated.
• The new findings can help us identify geologically active regions that require particularly close examination for future Venus missions. 

..."

From the abstract:

"Rifts are prominent tectonic features on Venus, yet their formation, evolution and tectonic activity remain debatable.

Here we conducted 3D numerical thermomechanical experiments with visco-elasto-plastic compressible rock rheology to systematically investigate the rifting dynamics and topography under Venusian conditions. To compare active and inactive rift morphologies, the relaxation of rift topography after extension ceases was also investigated.

Our modelling results suggest a relatively thick thermal lithosphere and a strong crust with dry diabase or mafic granulite rheology in rifted regions and demonstrate that wide rift flank uplifts strongly indicate either presently ongoing Venusian rifting or activity within the past few tens of millions of years.

The rift valleys in the Ganis, Dali and Devana Chasmata have wide rift flank uplifts, and their characteristic topographic features are comparable to the modelled early-stage active rifts undergoing relatively high extension rates of 3−10 cm yr−1.

This suggests that the Venus rifts in these regions are still active or were active very recently. Their morphology also indicates faster extension rates than commonly assumed for Venusian rifting, potentially associated with recent vigorous mantle plume activity."

ScienceAdviser

Venus: Dead? Far from it

Venus: Dead? Far from it (original news release) "Simulations conducted by researchers at ETH Zurich suggest a strong likelihood that Venus’s rift valleys are still geologically active rather than being mere relics of a bygone era, as had been previously believed. This finding reshapes our understanding of Earth’s sister planet and will influence future missions to Venus. "

Recent active rifting on Venus revealed by wide rift flank uplifts (open access)

There are huge rift valleys on Venus. They suggest that the planet is still geologically active. 

Neutrinos From Deep Inside Earth Provide a New Picture of the Mantle

Recommendable! Geoneutrinos versus Helioneutrinos!

"... This is the SNO+ neutrino experiment, buried deep within the Creighton mine at Snolab, an underground physics laboratory in Sudbury, Canada. SNO+ consists of an acrylic sphere lined with nearly 10,000 sensitive light detectors and filled with 780 tons of oily liquid scintillator, which flashes when lit up by energetic particles. The water around the device and the rock above it shield the detector from the glare of cosmic radiation, allowing the flickers of less common particle interactions to shine through. ...

Even more elusive — so much so that after decades of searching, scientists have detected only a few hundred of them — are geoneutrinos. ...

Geoneutrinos are produced in processes that heat the interior of the planet. This heat plays a major role in powering the flow of rocks in the mantle, which shapes everything from plate tectonics to Earth’s magnetic field.

It comes from two main sources:

heat left over from the planet’s formation, and

heat produced by the decay of uranium, thorium, and potassium in the rocks of the mantle and crust. ...

In counting geoneutrinos, physicists can get a direct measure of Earth’s vital heat-producing elements. ...

The first detection of geoneutrinos, by an instrument in Japan called Kamland, was reported in 2005.

In 2009, the Borexino detector in Italy reported catching several dozen more.

In November 2025, SNO+ reported(opens a new tab) its first detection, bumping up the number of observed geoneutrinos by about 50.

What makes the detections at SNO+ special is the experiment’s location: These are the first geoneutrinos measured in the western hemisphere, offering a new perspective on Earth’s radioactive interior.

Major uncertainties remain in interpreting the results from these experiments, but researchers’ best estimates suggest that each site is measuring a different flux. “It could be that that’s the first hint that the mantle is not uniform,” ..."

Neutrinos From Deep Inside Earth Provide a New Picture of the Mantle | Quanta Magazine "A global constellation of neutrino detectors is creating a never-before-seen view of the radioactive elements that power Earth’s tectonic heat engine"

The JUNO experiment, located outside the city of Guangzhou in China, is expected to report its first geoneutrino detections this year.

The SNO+ experiment sits deep underground, shielded from cosmic rays beneath 2 kilometers of rock.

What triggered one of the most dramatic changes in Earth’s history? The ups and downs of oxygen

Amazing stuff!

"... For its first 2 billion years, Earth had almost no free oxygen in its air or oceans. Then, some 2.45 billion years ago, the ancestors of photosynthetic cyanobacteria began to flood the world with oxygen, creating the conditions that allowed complex life to evolve and prosper. The Great Oxidation Event (GOE), as it’s known, is “the most fascinating and most dramatic change in how the Earth’s surface works in its history,”

But that story has clouded recently. Mineral analyses suggest oxygen-producing microbes evolved hundreds of millions of years before the GOE, leaving a huge, unexplained gap when oxygen remained low. And the GOE appears to have been not one event but several, with oxygen repeatedly rising and falling over a span of some 200 million years—a great oxidation followed by a great deoxidation, and then back again, several times. 

Now, possible explanations are emerging.

One talk at the Goldschmidt conference this month proposed that oxygen could not rise until extensive shallow areas formed in the world’s oceans.

Another argued the oxygen pulses reflect ancient Earth’s periodic transformation into Snowball Earth, when ice engulfed the planet to low latitudes. 

Yet a study last year in Nature reported carbonate deposits created by oxygen-producing cyanobacteria 2.85 billion years ago. Using the mutation rates of modern-day microbes to date the origin of photosynthesis pushed it back even further, to as much as 3.5 billion years ago. And for 2 decades, researchers have tracked what appear to be “whiffs” of oxygen prior to the GOE, recorded in minerals that require oxygen to form. ..."

From the abstract of the oral presentation:

"The rise of atmospheric oxygen and the onset of Paleoproterozoic glaciations are commonly attributed to biological innovation, particularly the emergence of oxygenic photosynthesis. Yet geochemical evidence indicates that oxygen production predated the permanent rise of atmospheric O₂, implying that biological capability alone was insufficient to drive sustained oxygenation. Here we present results from a coupled ocean–atmosphere box model demonstrating that continental growth and shelf emergence acted as tectonic gatekeepers of long-term atmospheric redox evolution.

We introduce the concept of a continental oxygen inventory, defined as the product of shallow continental shelf area and dissolved oxygen concentration, to quantify the spatial constraint on oxygen export from the ocean to the atmosphere. Model results reveal two critical thresholds.

When the relative inventory exceeds ~0.01% of its modern value, atmospheric O₂ surpasses the mass-independent sulfur fractionation (S-MIF) threshold (~10⁻⁵ PAL).

When it exceeds ~1%, enhanced methane oxidation drives atmospheric CH₄ collapse, triggering global glaciation. Below these thresholds, even oxygenated surface waters fail to oxygenate the atmosphere.

Because shelf area is ultimately controlled by continental crust volume, mantle thermal state, plate mobility, and hypsometry, these results imply that deep Earth processes fundamentally regulated the timing and magnitude of atmospheric oxygenation. The Great Oxidation Event, therefore reflects not solely biological innovation but the progressive expansion of oxygen-producing habitats enabled by tectonic evolution during late Archean–early Proterozoic continental growth.

More broadly, this work highlights tectonics as a first-order control on planetary oxidation state and climate stability. By linking mantle dynamics to atmospheric composition through evolving continental geometry, our framework reframes Earth’s oxygenation as a coupled deep Earth–surface process. These findings have implications not only for interpreting the tempo of Earth’s environmental and biological evolution, but also for assessing the likelihood of atmospheric oxygen accumulation—and thus detectable biosignatures—on rocky exoplanets with differing tectonic regimes."

What triggered one of the most dramatic changes in Earth’s history? | Science | AAAS

Continental Growth as a Tectonic Gatekeeper of Early Earth Oxygenation (an oral presentation)

How did mammals from North America move into South America millions of years ago

Amazing stuff!

"... researchers have found fossil evidence that animals from different latitudes of North America and South America mixed long before the Panamanian land bridge permanently linked the two continents about 3 million years ago.

Since around 10 million years ago, mammals — primarily small ones like sloths and coatis — found a way across the watery barrier. Only larger mammals had to wait for the permanent land corridor. ...

Biologists thought that only after the isthmus formed did animals surge north and south, what biologists refer to as the Great American Biotic Interchange or GABI. That resulted in the extinction of a lot of South American species as North American species took over.

Yet this picture of mammal movements across continents is too simple, ... paleontologists argue. After assembling and analyzing a new database of fossil mammals discovered in Mexico, they conclude that northern North American animals had already migrated into southern North America by about 10 million years ago, where they waited around in a kind of holding pen until opportunities arose for some of them to continue crossing to the south starting about 7 million years ago. ...

During that pre-GABI time, smaller mammals — heralded by racoon-like coatis and ringtails and small rodents — moved to South America via some kind of intermittent corridor, by island hopping through the Caribbean or by rafting on vegetation. Only one major South American group, the sloths, moved to North America. ..."

From the abstract of the Perspective:

"Whenever plants and animals newly come together, there will be some winners and some losers. This was the case for the Great American Biotic Interchange (GABI), which occurred ~2.8 million years ago (Ma), when the emergence of the Isthmus of Panama connected the continents of South and North America. Although species moved both northward and southward during the GABI, a massive taxonomic asymmetry arose between the two continents, with a much greater proportion of species in South America having a North American origin than the opposite. ... Tseng et al. report that a large fossil dataset from Mexico helps to uncover the events that primed mammals for movement across the Isthmus."

From the editor's summary and abstract:

"Editor’s summary

For millions of years after the breakup of the supercontinent Gondwana, South America was disconnected from other landforms, a time period that has been referred to as its “splendid isolation.”

This isolation allowed for the evolution of mammals with distinctive features, including xenarthrans, sprassodont carnivores, and notoungulates.

The formation of the Panamanian land bridge facilitated connection of North and South American faunas, with a bias from north to south. Tseng et al. looked at fossils from low latitudes in México and found that northern mammals accumulated in the region before the connection (see the Perspective by McGuire and Williams). This allowed for more rapid dispersal south and further supports that the land bridge first formed during the Pliocene rather than the Miocene. ...

Abstract

The movement of taxa between North and South America across the Panamanian land bridge, known as the Great American Biotic Interchange (GABI), established modern-day mammal assemblages in the Americas, heralding the decisive end of what has been called the “splendid isolation” of the South American fauna.

Lacking substantive low-latitude records, previous work on this pattern relied on South American and temperate North American fossils to conclude that pulsed interchanges began about 2.8 million years ago (mya).

Based on new low-latitude fossil data from México, we found evidence for a prolonged, triphasic interchange.

Phase 1 consisted of the initial accumulation of northern higher-latitude mammals in a Mexican “holding pen” beginning 10 mya. 

Dispersal began in phase 2, with a strong north-south gradient and increasing biogeographic connections (7 to 3 mya).

The final phase consisted of the already well-described taxonomic pulses (from ~2.8 mya)."

ScienceAdviser

When mammals crossed between continents (no public access)

North and South America weren’t always connected, but their mammals still found a way to intermingle (original news release) "Before the Panamanian land bridge formed about 3 million years ago, mammals on the two continents were isolated — or so biologists thought. New fossils show that they found ways to mix long before that."

A 10-million-year biogeographic holding pen primed the Great American Biotic Interchange (no public access) "Before the Panamanian land bridge formed about 3 million years ago, mammals on the two continents were isolated — or so biologists thought. New fossils show that they found ways to mix long before that."

This illustration depicts (left) large North American mammals — counterclockwise from top, mammoths, llamas, tapirs, peccaries and saber-toothed cats — waiting in a kind of holding pen in Mexico for the bridge to form.

In South America, the mammalian interchange involved, counterclockwise from top, ground sloths, marsupials, capybaras, armadillos, glyptodonts and, incidentally, terror birds. While North American mammals took over in South America, only about 10% of North American mammals today are derived from mammals that originated in South America.

Fervo Energy, a geothermal energy company, has drilled its deepest and most complex well yet in Utah

Food for thought!

If geothermal energy were to be implemented at large scale and worldwide, then the environmental and geological consequences could be enormous. Call me skeptical as far as geothermal energy is concerned.

Make no mistake to confuse geothermal energy with so-called renewable energy (wind and solar power)!

"Fervo Energy, a geothermal energy company, has drilled its deepest and most complex well yet, reaching a measured depth of nearly 19,500 feet in just 21 days. The new well, Sawtooth 7, will contribute to a 400-megawatt geothermal power project in Utah scheduled to begin delivering electricity in 2028."

Doomslayer: Progress Roundup - by Malcolm Cochran

Fervo Energy Sets Drilling Record with Sawtooth 7 Well

Fervo Energy sets drilling record with Sawtooth 7 well

Fervo Energy Learning Curve Continues on 3rd Generation Well Design, Boosting Drilling Rates by 143% Since Its First Cape Station Well (original news release) "Sawtooth 7 sets a new drilling pace record, reaching 19,448 feet measured depth with a 7,500-foot lateral in 21 days"

Web page of company. Carbon free??? Really!

Company provided table

Cooler Earth core could solve Earth’s magnetic mystery

Amazing stuff! In the age of so called "climate change" and global warming hoax when cooler heads will hopefully prevail!

"New experiments suggest Earth’s iron core could be more than 1000°C cooler than longstanding estimates, potentially resolving a puzzle that has vexed geophysicists for decades.

By squeezing iron to nearly 2 million atmospheres between diamond anvils and heating it with rapid electrical pulses, researchers measured iron’s melting point at corelike conditions and found it melts at much lower temperatures than previous studies suggested. The result could help explain the so-called “new core paradox.”

Earth’s magnetic field has existed for at least 4 billion years. But many thermal models indicate the solid inner core—which as it slowly freezes today helps power the magnetic dynamo in the molten outer core—formed only about 500 million years ago.

The new measurements suggest the core lost heat more slowly than previous models assumed, allowing heat-driven convection alone to power the magnetic dynamo for most of Earth’s history, without requiring an ancient inner core. ..."

"... Today, that dynamo is sustained mainly by the slow freezing of the inner core, which releases heat and buoyant light elements into the liquid metal above. But some models of Earth’s cooling history suggest the inner core began to form just over half a billion years ago, raising the so-called “new core paradox”: What kept the dynamo running for the 3.5 billion years before the arrival of the inner core? ..."

From the abstract of the oral presentation:

"The melting temperatures and electrical resistivity of iron at high pressure are essential for understanding the thermal history and dynamics of Earth’s core, but significant differences in experimental results have led to divergent Earth models. We developed a pulsed Joule heating system to investigate the melting temperature and electrical resistivity of iron under the high pressure of Earth’s core. The system heats metal samples to temperatures exceeding 4000 K at pressures exceeding 2 Mbar. Precise sample fabrication, combined with a novel 5-color multianode spectroradiometer, enables high-precision heating control and temperature measurement (~ ±30 K) with sub-microsecond time resolution. Plateaus in temperature-time traces due to the latent heat of melting show outstanding reproducibility.

Our findings on the high-pressure melting curve of iron, based on more than 200 melting measurements extending to over 2 Mbar, reveal lower melting temperatures and a shallower Clapeyron slope relative to previous studies.

By extrapolating these to inner-core pressure and combining them with our measured resistivity of liquid iron (~75 μΩ cm), we propose that a relatively low adiabatic outer-core heat flow of < 10 TW and relatively low core-mantle boundary temperatures.

Our results indicate that thermal convection alone may have powered the geodynamo before the formation of the inner core, and that today’s lowermost mantle is likely to be fully solid."

ScienceAdviser

Earth’s core may be far cooler than scientists thought (partial public access)

High-pressure melting and resistivity of iron with implications for Earth’s core and lowermost mantle (oral presentation)

Undersea lava flows named after Game of Thrones dragon may reveal a new type of volcanism

Amazing stuff!

Unfortunately, it appears neither the King Abdullah University nor the Helmholtz Centre for Ocean Research posted any news release on this discovery!

"The Atlantic Ocean’s Balerion Lava Field doesn’t fit any established model of volcanic eruptions"

"A glassy swath of lava discovered on the floor of the Atlantic Ocean doesn’t fit any existing explanation for how volcanoes form. Named the Balerion Lava Field after the gargantuan black dragon from the TV series Game of Thrones, it may represent a previously unrecognized form of volcanism lurking across Earth’s still mostly unexplored sea floor. ...

But the Balerion Lava Field—located in the northwestern Atlantic far from any subduction zone, midocean ridge, or known hot spot—fits none of these categories. ..."

From the abstract:

"The abyssal plains cover more than half of Earth’s surface and are generally regarded as volcanically and hydrothermally inactive environments that progressively accumulate pelagic sediments with age. This assumption is the basis for models on e.g., oceanic crust evolution, chemical budgets of the deep ocean floor, and the distribution of hard-substrate benthic habitats.

Here, we present high-resolution acoustic data, seafloor observations, and sample characteristics from the NW Atlantic abyssal seafloor that reveal 360 km2 of young (<50 ka) volcanism on 20 Ma oceanic crust. 

These Balerion Lava Fields do not display a significant bathymetric expression and are only detectable from the surface by a stronger acoustic backscatter, pointing to limited sedimentation.

Geochemistry of the lavas reveals that the lavas are Si-saturated basaltic andesites with low Ca and Fe at relatively high Mg contents. Whole rock trace element and elevated Ni, low Ca/Fe olivine chemistry signatures resemble those of Hawaiian samples from Koʻolau and Mauna Loa that have been linked to pyroxenite-bearing mantle sources. 

Isotopic compositions are close to the PREMA mantle domain. Small (<1 mm), skeletal phenocrysts suggest rapid crystal growth and ascent of low-viscosity, possibly superheated melts with little or no crustal storage.

Regional bathymetry and tectonic structure are consistent with normal 20 Ma seafloor subsidence and deformation, providing no evidence for anomalous lithospheric thinning, intraplate extension, or a mantle thermal anomaly.

Instead, the geochemical characteristics point to magma generation at >2 GPa from a pyroxenite-rich source within the asthenosphere [cf. 4].

We propose that the Balerion volcanism reflects melting of anomalous volumes of recycled oceanic crust, rising in the convecting upper mantle. Such processes may occur widely beneath oceanic plates, representing a form of intraplate magmatism independent of both plate tectonics and mantle plumes."

Undersea lava flows named after Game of Thrones dragon may reveal a new type of volcanism | Science | AAAS

Hidden, young lavas on the 20 Ma old abyssal plain: A new form of oceanic intraplate volcanism

A crystal of olivine in a sample of seafloor lava that resembled a dragon prompted researchers to name the eruptive flow Balerion, after a Game of Thrones dragon

Where Did Earth Get Its Oceans? Maybe Earth did it

Recommendable!

"... It may come as a surprise, then, that scientists don’t really know how water first arrived here on Earth. ...

When astronomers look at exoplanets — worlds outside our solar system — they see a diversity of atmospheres. But when they simulate the ways the planets took shape, scientists find that many of them could have started out brimming with hydrogen. Could Earth’s formative years have been similar? ...

But in recent years, several spacecraft caught up to comets to examine them. What they found was that cometary water didn’t match ours; the chemical signatures were different. ...

Asteroids — rockier and more metal-rich than comets — then became the most popular choice. Asteroids impact Earth far more frequently than comets do, and their water reserves (while not as voluminous as those of comets) look a lot more like those on our planet. ...

Through careful observation of worlds orbiting other stars, along with some explosive laboratory experiments involving diamond anvils and lasers, scientists have realized that rocky planets like Earth have a way to make water all by themselves. All you need is an ocean of magma, a whole lot of hydrogen, and a little bit of geological alchemy. ...

asteroids. These rocky objects mostly hang out between Mars and Jupiter, and they impact our planet all the time as meteorites, though most of their material burns up in the atmosphere or lands in the ocean. Scientists have collected tens of thousands of meteorites and found that the water molecules contained in a particular group closely resemble those in our world. ...

But some studies ... found that there was hydrogen in the meteorites all along. It was just hidden in their organic molecules, silicate glasses, and sulfur compounds. Perhaps, then, Earth was also awash in hydrogen in its early days.

Earth’s ocean of magma was full of oxygen. In a paper published in 2023, three scientists wondered what might happen if the hydrogen in a planet’s atmosphere and the oxygen in its magma were to mix — somehow. Hydrogen doesn’t just spontaneously bind to oxygen, so they aren’t the most willing chemical partners. Still, the researchers concluded that such a process would let a planet make its own water; they just weren’t sure how much.

Two years later, they were thrown a lifeline by an ambitious set of experiments built by the researchers ...

how sub-Neptunes, commonplace exoplanets two to four times the diameter of Earth, can have atmospheres rich in water, as telescopic observations suggest, even when they hew close to their scorching-hot host stars. ...

if a huge amount of hydrogen put the magma under a sufficient amount of pressure. “That higher pressure is a big part of what facilitates the water production,” ... “It actually enhances the chemical reactions.” ...

To test their model, the team wanted to re-create the extreme (and extremely dangerous) conditions present on adolescent sub-Neptunes. They needed to put hydrogen, a highly flammable gas, under intense pressure using special tools called diamond anvils, and then combine it with rock samples melted with lasers. It took them five years to develop the techniques they needed to conduct these experiments safely and effectively. ...

They had hoped the hydrogen and oxygen would react to make water. And that’s what happened, to the extreme: The reaction of high-pressure hydrogen and laser-melted rock was so efficient that it made up to 1,000 times more water than scientists predicted. (A second laboratory study, published around the same time, reported similar results.) “It doesn’t seem unreasonable [that you could] produce a huge amount of water quite quickly,” ..."

Where Did Earth Get Its Oceans? Maybe It Made Them Itself. | Quanta Magazine "At first, scientists thought Earth’s water came from comets. Then, asteroids. Now, they wonder if Earth’s water is homegrown."

A Day on Earth Is Getting Longer as the Planet’s Rotation Slows. Really!

When the Wall Street Journal publishes a popular science article! When obsessions interfere with rational thinking!

I would argue this tiny number could well be within the range of a measurement error! Plus, these are not measurements, but computer modeling results. Junk science?

"The Number ~1.33 The milliseconds added to day length per century over the past two decades, according to a new study. As temperatures warm, ice in the Arctic, Greenland and Antarctica melts, and the resulting rise in sea levels slows down Earth’s rotation. A change of milliseconds seems insignificant, but it can cause problems for clocks, GPS and navigation apps, and satellites."

"Climate change is lengthening our days because rising sea levels slow Earth's rotation. Researchers from the University of Vienna and ETH Zurich now show that the current increase in day length — 1.33 milliseconds per century [???]— is unprecedented in the past 3.6 million years [???]. The team reconstructed ancient day-length fluctuations using the fossil remains of single-celled marine organisms known as benthic foraminifera. The study has just been published in the Journal of Geophysical Research: Solid Earth. ..."

From the abstract:

"Understanding the history of Earth rotation variations and its connection to mantle dynamics is one of the most important problems is global geophysics. However, our knowledge of these variations—in particular those induced by climate on geological timescales—is limited due to both modeling deficiencies and the scarcity of paleoclimate data.

In order to advance our understanding of this problem, here we first develop a new probabilistic deep learning methodology called Physics-Informed Diffusion Model (PIDM). We then use PIDM in conjunction with the recently available paleoclimate data—specifically, sea level variations since the Late Pliocene—to precisely reconstruct the history of climate-induced changes in the Earth's rotation rate (i.e., Length of Day variations: 

LOD). We reconcile LOD inferred from various climate models and paleoclimate proxies (i.e., geological records such as fossil benthic foraminifera and coral reefs). Based on our reconstructions of LOD, we unravel

(a) large-amplitude fluctuations due to Quaternary ice ages, surpassing the magnitude of the currently known processes including those of atmosphere, land hydrology, and core,

(b) a previously unrecognized secular trend due to changes in the Earth's oblateness caused by the outset of Northern Hemispheric ice sheets, and

(c) the almost unprecedented rate [???] of increase in the length of day caused by century climate change."

Wall Street Journal What's news

A Day on Earth Is Getting Longer as the Planet’s Rotation Slows - WSJ "A change of milliseconds seems insignificant, but it can cause problems for our clocks, GPS and navigation apps, and satellites"

Climate change slows Earth's spin: Day lengthening unprecedented in 3.6 million years (original news release from March 2026) "Comparing fossil archives with modern measurements – Today's increase in day length stands out clearly in climate history"

Climate-Induced Length of Day Variations Since the Late Pliocene

Earthquake-sensing fiber cables can also pick up speech from other, nearby fiber cables

Amazing stuff!

What is the definition of serendipity?

"Fiber optic cables used to detect earthquakes may also be able to eavesdrop on nearby conversations. Researchers reported last week at the European Geosciences Union meeting that distributed acoustic sensing (DAS) can accurately capture the faint vibrations of human speech.

DAS works by firing laser pulses down a fiber cable and measuring tiny changes in any light that reflects back. Geophysicists increasingly use the technique to study earthquakes, volcanoes, traffic, and even pedestrian footfalls, taking advantage of both dedicated research cables and unused “dark fiber” already buried beneath cities and oceans.

But in field tests, researchers found that exposed, coiled cables could also pick up nearby speech from several meters away. Feeding the signals into Whisper, a free AI transcription tool, produced readable real-time transcripts.

“Not many people realize that [fiber optic cables] can detect acoustic waves,” said geophysicist Jack Lee Smith. “This could be a privacy concern.”

The effect was limited: buried cables and straight fiber lines recorded speech poorly. Still, researchers say the findings highlight unexpected privacy risks as DAS use expands."

ScienceAdviser

Fiber optic cables can eavesdrop on nearby conversations "Cables used to detect earthquakes can also capture the faint vibrations of speech"

Deep-Earth map reveals a lost U.S. continent

Amazing stuff!

Too bad, I was not able to find an image of this former continent using Google and Bing search.

"Along the eastern front of the Appalachian Mountains, buried just below the surface, lies a fragment of a lost continent. Running from Maine to Georgia, the 200-kilometer-thick slab of crust was probably created by volcanic eruptions during the breakup of the Pangaea supercontinent some 200 million years ago and later buried by silt from eroding mountains.

Known as the Piedmont Resistor, this piece of Pangaea is one of the signature discoveries of the Magnetotelluric (MT) Array, 1800 temporary stations scattered across the contiguous United States that measured the conductivity of deep rocks. Now, 20 years after it started, the MT Array has released its final map and model ... It shows how the assembly of the continent left hidden structures such as the Piedmont Resistor—and mineral riches. ..."

From the abstract:

"The United States Magnetotelluric Array (USMTArray) data set, collected in the years 2006–2024, consists of more than 1,700 long-period magnetotelluric stations covering the entirety of the contiguous United States on a quasi-regular 70 km grid. ...

Together with parallel advancement in the development of publicly available three-dimensional (3D) inversion codes, the USMTArray has revitalized the US magnetotelluric community and increased the visibility of magnetotellurics within the Earth-science community.

Taken as a whole, these data are visualized as the National Impedance Map, which, together with a 3D synthesis conductivity model of the nation, reveals the electrical architecture of the contiguous US. USMTArray data are used by researchers worldwide for fundamental and applied studies, including investigations of continental architecture and evolution, estimation of hazards to critical infrastructure due to geomagnetic storms, and assessment of the nation's undiscovered geothermal and mineral resources.

We here review the history and development of the project, discuss the challenges and successes in its execution, present the National Impedance Map and synthesis conductivity model, and highlight the breadth of research stemming from this rich data set."

Deep-Earth map reveals a lost U.S. continent | Science | AAAS "Sensor array traces how rocks conduct electricity, exposing ancient continental fragments, mineral targets, and grid hazards"

The United States Magnetotelluric Array and the National Impedance Map (open access)

US Geological Survey recently estimated that there are over 2 million metric tons of undiscovered, economically recoverable lithium in the Appalachian Mountains

Good news!

"The United States Geological Survey recently estimated that there are over 2 million metric tons of undiscovered, economically recoverable lithium in the Appalachian Mountains, enough to supply the country for centuries at current levels of consumption."

"“The southern Appalachians hold an estimated 1.43 million metric tons of lithium oxide, concentrated in the Carolinas, and

the northern Appalachians hold an estimated 900,000 metric tons, concentrated in Maine and New Hampshire, according to estimates in a new USGS scientific paper published in Natural Resources Research. The lithium is present in pegmatites, large-grained rocks similar to granite. ..."

Doomslayer: Progress Roundup - by Malcolm Cochran

Lithium in Eastern States Could Replace Imports for a Century

https://www.usgs.gov/news/national-news-release/lithium-eastern-states-could-replace-imports-a-century-or-more

Plate tectonics is even older than we thought

Amazing stuff!

The author of the Perspective abstract below is obsessed with Global Warming/Climate Change: "The movement of tectonic plates—massive slabs of rock—over Earth’s surface controls the planet’s habitability by sustaining the carbon cycle that regulates the climate" (The first sentence of the abstract) I have serious doubts that this is correct!

From the Perspective abstract:

"The movement of tectonic plates—massive slabs of rock—over Earth’s surface controls the planet’s habitability by sustaining the carbon cycle that regulates the climate [???] and stabilizes liquid water at the surface .
It also facilitates efficient planetary heat loss, thereby maintaining convection in Earth’s core and the generation of a magnetic field. The presence of a magnetosphere—a space around Earth dominated by its magnetic field—provides shielding from solar and cosmic radiation and mediates the loss of atmospheric gas into space. Deciphering plate motions in Earth’s early history can thus hint at how the planet looked several billion years ago. On page 1278 of this issue, Brenner et al. (2) report differential plate motion 3.5 billion years (Ga) ago by recovering ancient magnetic field records from rocks in Australia. This may provide clues to the nature of early tectonic motions and their role in sustaining habitable conditions."

From the editor's summary and abstract:

"Editor’s summary

Plate tectonics is a global recycling process that underpins most of Earth’s systems. Its onset remains an open question because of sparse early geologic records. Brenner et al. collected paleomagnetic data from approximately 3.4 billion-year-old rocks in Western Australia and compared them with existing data from rocks of the same age in South Africa (see the Perspective by Nichols). They detected diverging paleolatitudes, two crustal blocks moving differently around the same magnetic pole. The rate of motion is consistent with aspects of modern plate tectonics but could reflect an earlier style. This plate motion was occurring against the backdrop of the oldest known geomagnetic reversal, which was also discovered from these data.

Abstract

Whether early Earth had a mobile lithosphere and plate tectonics is debated. We present paleomagnetic data quantifying differential motion between lithospheric blocks at ~3.48 billion years ago (Ga). This manifested as 

centimeters per year latitudinal motion of the East Pilbara Craton (Western Australia) across high latitudes, whereas the Barberton Greenstone Belt (South Africa) was stationary at low latitudes. Comparison of this plate motion with candidate analogs suggests either rapid collisional plate tectonics (i.e., an “active-lid”) or an episodically mobile lithosphere. We also document the oldest known geomagnetic reversal at ~3.46 Ga, consistent with an axial dipolar dynamo that reversed less frequently than today’s. The existence and rates of these surface and core geophysical phenomena provide geodynamic context to Earth’s early geophysical and biological evolution."

ScienceAdviser

Ancient rocks reveal early plate motions (Perspective, no public access)

Paleomagnetic detection of relative plate motions and an infrequently reversing core dynamo at 3.5 Ga (no public access)