Saturday, 28 March 2026

Can Volcanoes be Connected?

 Can Volcanos be Connected?

A correspondent has sent me THIS ARTICLE. For ever geologists have thought that volcanoes could be studied in isolation but, more recently it has been discovered that magma does not just travel towards the surface but can also go sideways - it can move from one volcano to another, sometimes many kilometres apart. And, sometimes the type of rock erupted can change - which seems very odd.

Iceland’s Fagradalsfjall fissure system erupted multiple times between 2021 and 2023, after which the Svartsengi fissure system seemed to take its place.

The article in Quanta Magazine (which has some wonderful photos) describes, at length, coupled volcanos. I recommend reading it. I attach a summary produced by ChatGPT.

The Quanta Magazine article “When Coupled Volcanoes Talk, These Researchers Listen” explores a growing realization in volcanology: volcanoes are not always isolated systems, but can be physically connected and interact through shared underground magma pathways. By tracking how magma moves between volcanoes, scientists are uncovering “conversations” between volcanic systems that could improve eruption forecasting and deepen understanding of Earth’s interior dynamics.

The article begins with the famous 1912 eruption in Alaska involving Mount Katmai and the Novarupta vent. For decades, scientists assumed Katmai itself erupted and collapsed after expelling its magma. However, later geological mapping revealed that the eruption actually occurred about 10 kilometres away at Novarupta, which had effectively drained magma from Katmai. This discovery provided early evidence that magma can move laterally across significant distances, linking separate volcanic structures.

Modern research has expanded on this idea, showing that such connections are not rare. Advances in monitoring technologies—such as seismometers that detect magma movement and satellite-based measurements of ground deformation—allow scientists to track magma migration in near real time. These tools reveal that magma does not always rise vertically, as once assumed, but can flow sideways through complex subterranean networks.

A key focus of current research is Iceland’s Reykjanes Peninsula, where volcanic systems appear to operate in sequence. After eruptions at one fissure system, activity can shift to another nearby system, suggesting that magma is redistributed underground. This behaviour gives the impression that volcanoes are “talking” to each other—when one system quiets down, another becomes active. Such patterns indicate that volcanic regions may function as interconnected networks rather than independent vents.

Scientists are now attempting to map these hidden magma pathways and understand the physical mechanisms behind them. Magma behaves like a complex fluid mixture, with its viscosity depending on composition—silica-rich magma is thicker, while low-silica magma flows more easily. These properties influence how magma travels through the crust and how it links different volcanic systems.

Understanding these connections has practical importance. If magma can shift from one volcano to another, monitoring a single volcano in isolation may be insufficient for predicting eruptions. Instead, researchers must consider entire volcanic regions as integrated systems. By identifying patterns of magma transfer, scientists hope to anticipate where eruptions might occur next, even if the triggering signals originate elsewhere.

Ultimately, the research highlights a shift in how volcanologists conceptualize volcanic behaviour—from isolated eruptions to dynamic, networked systems. By “listening” to how volcanoes interact through shared magma, scientists are developing a more nuanced and predictive understanding of volcanic activity. This approach could lead to better hazard assessments and earlier warnings for communities living near active volcanic regions.


 

What Caused the Younger Dryas

 What Caused the Younger Dryas

The Younger Dryas was a cold period which started 12,870 years ago. The last glacial maximum had finished about 20,000 years ago, so there had been about 7,000 years when things had been getting warmer. At 12,870 years ago thing got cooler quickly - in Europe the average temperature dropped 6⁰C in just 3 years! I suspect this would make life difficult for the people in the area. This cooling lasted for 1,170 years.

The causes of this are discussed in THIS ARTICLE, partially based on this JOURNAL ARTICLE, and this MAGAZINE ARTICLE. Possible culprits include:
  1. A meteor strike

  2. Drainage from a large glacial lake, disrupting the North Atlantic Drift.

  3. An unknown volcanic eruption. (But not the Laacher See eruption - wrong trace elements and a bit later than the start of the Younger Dryas.)
There is evidence of volcanism at the start of the Younger Dryas. Where it was is still unknown. But the meteor strike is now discounted. We are left with culprits 2 and 3. And they do not rule each other out.

Below I attach a summary of the article which started this post, produced by ChatGPT.

The Earth-logs article argues that the long-debated cause of the Younger Dryas cold interval—an abrupt return to near-glacial conditions about 12,870 years ago—is now effectively resolved. The Younger Dryas interrupted the gradual warming that followed the last Ice Age, with temperatures in parts of the Northern Hemisphere dropping dramatically within just a few years and remaining cold for over a millennium.

Historically, several explanations have competed. One popular idea was that a massive influx of freshwater into the North Atlantic disrupted ocean circulation, particularly the Gulf Stream, reducing heat transport to higher latitudes. Another controversial hypothesis proposed that a comet or asteroid impact triggered the cooling, but this has largely been rejected due to lack of reproducible evidence.

The Earth-logs post highlights newer geochemical and ice-core evidence that points instead to a major volcanic trigger. Ice cores from Greenland show a pronounced sulphate spike at the onset of the Younger Dryas, indicating a very large volcanic eruption. While the well-known Laacher See eruption in Germany occurred around the same time, its scale and chemical signature do not match the observed sulphate anomaly. This implies that a much larger, as yet unidentified eruption injected vast quantities of aerosols into the atmosphere.

Such an eruption would have rapidly reduced incoming solar radiation, causing sharp cooling. Crucially, this initial volcanic cooling could have pushed the climate system past a tipping point, weakening ocean circulation and locking the Northern Hemisphere into a prolonged cold state. In this view, volcanism acted as the trigger, while feedbacks within the ocean–atmosphere system sustained the millennium-long chill.

The article concludes that this combined explanation—a large volcanic event initiating a cascade of climatic feedbacks—best fits the available evidence. It reconciles the abrupt onset seen in ice cores with the extended duration of the Younger Dryas, offering a coherent solution to a long-standing geological puzzle.

Thursday, 26 March 2026

Down to Earth Extra April 2026

 Down to Earth Extra April 2026

The April 2026 edition of Down to Earth Extra has been published. you can download it HERE or you can read it below.


Saturday, 21 March 2026

Subducted Slabs - Where and How

Subducted Slabs - Where and How

Earth-Logs, one of this blogs favourite sources has come up with an interesting article which you can find HERE. It is based on THIS ARTICLE which will appear in a Nature Journal soon.

It concerns subducting plates and what happens to them. It is thought that mineral density changes are the main control, but the authors of the paper suggest that another control is viscosity changes caused by cooler slabs entering the mantle. Their paper is summarised below (by ChatGPT) and further summarised in the diagram at the bottom of this page.

This is fascinating stuff but all the evidence is gained at a distance and we will never get there. So we have to be content with speculating about phase changes and viscosity. But these are the best explanations we have for the observations we make.

Seismic tomography does not support the idea that oceanic slabs sink intact all the way to the core–mantle boundary. Instead, many slabs stall and accumulate at depths around 660 km and 1000 km. The 660 km boundary is reasonably explained by pressure-driven mineral changes (especially in olivine) that increase density and resist further sinking. However, no equivalent mineral transition explains stagnation at ~1000 km depth.

Recent research by Jing Li and colleagues proposes that variations in mantle viscosity, rather than just mineral density changes, control slab behaviour. Their combined experimental and modelling work suggests that as slabs descend, they trigger recrystallization in the surrounding mantle, reducing grain size and creating localized low-viscosity zones. These zones can either facilitate or hinder slab movement, leading to complex, uneven descent.

They identify four subduction modes depending on trench retreat speed and mantle properties:

  • Slow retreat + low-viscosity patches → slabs penetrate past 660 km but stagnate at ~1000 km
  • Slow retreat + uniform mantle → slabs buckle between 660–1000 km
  • Fast retreat (with or without low-viscosity zones) → slabs stagnate at ~660 km

The study also suggests that older, “fossil” slabs may weaken the mantle and create low-viscosity regions that influence later subduction. These processes help explain seismic observations and imply that the mantle is highly heterogeneous.

Overall, the findings highlight that mantle dynamics are complex, with past tectonic activity influencing present-day plate motion, deep mantle convection, plume formation, and the chemical diversity of mantle-derived magmas.




Thursday, 12 March 2026

The Silverpit - an Impact Structure

 The Silverpit - an Impact Structure

A correspondent brought THIS ARTICLE to my attention. It is based on THIS ACADEMIC PAPER.

I am getting up to speed with Artificial Intelligence (AI) and used ChatGPT to summarise the Science Daily article. I think it did a pretty good job. 

(I am using this free, Bristol University, COURSE to further my knowledge of AI. It seems pretty good so far.)

A recent study has provided strong new evidence that the Silverpit structure beneath the southern North Sea was created by an asteroid impact rather than by geological processes such as salt movement. The feature, first identified in seismic survey data collected during North Sea oil exploration in the early 2000s, had long been debated among geologists. Researchers from Heriot-Watt University have now used improved seismic imaging together with mineral analysis to support the impact interpretation.
According to the study, the impact occurred about 43–46 million years ago, during the Eocene epoch. Scientists estimate that the asteroid responsible was roughly 160 metres in diameter. When it struck the seabed, the collision released immense energy, excavating a large crater and ejecting vast quantities of rock and sediment into the surrounding environment. Seismic data reveal circular structures typical of impact craters, while rock samples show signs of shock metamorphism—microscopic changes in mineral structure produced by extremely high pressures, which are characteristic of meteorite impacts.
The consequences of the collision would have been dramatic. The impact likely generated a massive tsunami, possibly exceeding 100 metres in height, that would have spread across the ancient North Sea basin. Such a wave could have flooded nearby coastlines and significantly altered local landscapes. The event would also have produced a large plume of debris, water, and vapour thrown high into the atmosphere.
For years, many scientists suggested the Silverpit feature might instead be the result of salt tectonics, a process in which underground salt layers move and distort surrounding sediments. The new combination of geophysical and mineralogical evidence, however, provides the clearest support yet for the impact hypothesis.
By confirming the origin of the Silverpit crater, the research adds another entry to the record of asteroid impacts on Earth. It also highlights that significant ocean impacts capable of generating large tsunamis have occurred within relatively recent geological time.






Tuesday, 24 February 2026

Down to Earth Extra March 2026

 Down to Earth Extra March 2026

The March 2026 edition of Down to Earth Extra has been published. You can download it HERE or you can read it below.


Saturday, 21 February 2026

Smiling Crinoids

 Smiling Crinoids

Several people have brought THIS WEB PAGE to my attention and I had spotted it myself. It is a story which ticks so many boxes! Amateur fossil hunter, St Cuthbert, Holy Island and a truly wonderful fossil!

Read the web page and it tells a great story. What I find most interesting is how a very common fossil gets to look like a set of false teeth! 

I wish I had found it!!!