A giant volcanic eruption acted a little like Vesuvius, but across an entire landscape in the Andes, burying the terrain beneath it and preserving information that would otherwise have been lost to erosion and deformation. Recently, the researchers looked at this vast expanse of volcanic rock that erupted from the Lauca Caldera in northern Chile 21.9 million years ago. A caldera is a large volcanic depression formed during major eruptions. A mountain’s worth of rock, called ignimbrite, covered an area six times larger than Chile’s capital Santiago (or nearly three times larger than Greater London), reaching a kilometre deep in places.

The research team simulated hundreds of possible ancient landscapes, using models of how rivers shape mountain ranges, to test which ones could plausibly have been buried beneath the volcanic deposit. They found that only relatively low-relief landscapes – akin to gentle mountain foothills – could have done so. ¹

From this, the team inferred that this part of the Andes was being built slowly, with rocks pushed upward by no more than a quarter (0.26) of a kilometre every million years – equivalent to 2.5 cm, or about an inch, every 100 years.

If rocks had been pushed upward faster in this region, the landscape would probably have developed steeper slopes that could not have fitted beneath the immense volcanic deposits.

The finding lends support to the idea that the Andes grew slowly and steadily over tens of millions of years rather than popping up more recently, in the last few million years.

This rate is slow compared with many rapidly uplifting parts of active mountain belts, including parts of the Himalaya, where uplift and erosion can occur at rates of several millimetres to centimetres per year.

A hidden ‘Pompeii’ of Andean landscapes

Lead author Dr Byron Adams, based at UCL Earth Sciences, said: “This landscape was buried by a giant volcanic eruption – a little like Pompeii, but on a vastly larger scale. Instead of covering a town, hot mixtures of volcanic ash, rock fragments, and gas swept across an entire landscape, engulfing the terrain beneath them.

“Pompeii shows how volcanic eruptions can freeze a moment in human history. This study shows that much larger eruptions can also freeze moments in Earth history, burying whole landscapes beneath volcanic deposits and preserving clues to how mountains were being built before the eruption.

“We cannot dig down to see the buried landscape, but we can use the shape of the volcanic blanket and what we know about how rivers shape mountains to infer what is hidden beneath it.”

A new way of piecing together geological history

The paper’s authors noted their estimate of rock uplift was consistent with earlier research looking at minerals in the rock that recorded specific changes in temperature over the last 50 million years. These changes of temperature represent the rock cooling as it travels upward through the Earth’s crust.

Dr Adams added: “This approach gives us a new way to look back at Earth’s history. Current methods to estimate the speed at which mountains build look at chemical ‘clocks’ in the rock but these are limited to specific moments in time. Our method can estimate rock uplift over a much longer period.

“In this case, we estimate it would have taken millions of years to produce the subdued landscape we infer prior to the eruption.

“There is debate over whether the Andes grew slowly and steadily over 40 or 50 million years or whether they rose extremely slowly and then popped up more recently, in the last six to 10 million years. Our findings, which cover a large part of the middle of that history, support the slow but steady hypothesis.”

Co-author Dr Frances Cooper, also based at UCL Earth Sciences, said: “We’ve been working in this part of the Andes for many years to understand how the mountains developed. The Andes have a major influence on regional and global climate, so reconstructing their history is important for understanding long-term climate change.

“What’s particularly exciting about this study is that it gives us a new way of piecing together that history. The same approach could be applied to volcanic deposits elsewhere in the world, helping us reconstruct landscapes buried for millions of years.”

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Author: Richard de Grijs, Professor of Astrophysics, Macquarie University

 

How do you explore a place where the Sun never shines? China’s space programme will soon embark on one of the most innovative lunar exploration missions in recent years.

We’ve known for nearly two decades that some form of water exists on the Moon. What we still don’t know is exactly how much accessible water ice lies inside permanently shadowed craters, how deeply it is buried or what form it takes.

What we do know is that accessing that water ice will be a real challenge: it is found at the bottom of deep, hard-to-traverse craters where the Sun never shines, remaining untouched for billions of years at temperatures well below –200°C. These are among the most valuable places on the Moon, but the hardest to reach and explore.

Lunar exploration has come a long way since the Soviet Union’s Luna-1 probe reached the Moon’s vicinity in January 1959. The Apollo missions and their successors showed the challenge is no longer simply to reach the Moon. It is to explore places human and conventional rovers cannot easily go, and ultimately determine whether the Moon itself can provide some of the resources that future explorers will need.

China has spent two decades building an increasingly ambitious lunar exploration programme, named after Chang’e, the ancient Chinese goddess of the Moon. The Chang’e-7 mission is expected to set course for our celestial neighbour later this month, although a recent failure involving a different Chinese rocket has introduced some uncertainty over the launch date. Here’s what makes this latest mission so interesting.

What is Chang’e-7 set to achieve?

The mission will test several novel approaches to lunar exploration. It will consist of an orbiter, a lander, a rover and a hopper.

In addition, the Queqiao-2 lunar relay satellite is already in place. Launched separately in March 2024, it subsequently supported the Chang’e-6 mission and will facilitate communication between Earth and the lunar surface during the Chang’e-7 mission.

We don’t know precisely where the mission will land, but a site on or near an illuminated ridge close to the Shackleton crater in the Lunar South Pole’s Aitken region is a prime candidate.

The hopper will be the mission’s real star. Unlike a wheeled rover, it’s designed to leap over broken terrain and descend into craters where sunlight never reaches, places conventional vehicles may simply be unable to enter.

Adding it to the mission makes sense, given the steep crater walls, broken terrain, permanent shadow and the need for autonomous navigation and communications.

Chinese scientists won’t be looking for signs of water; we already have compelling evidence for lunar polar water. The question at the mission’s core is where exactly that water is located, in what form and concentration, and whether it could realistically be accessed.

This marks a transition from simply exploring the Moon to determining whether its resources can actually be used.

How NASA is taking a different tack

Other nations are similarly interested in addressing that same question. The United States is pursuing the same longer-term objective of making sustained lunar operations possible. Although NASA will be confronted by the same physical problems, the American space agency has opted for a different solution.

Chang’e-7 is a coordinated state mission whose elements have been designed around a single, specific objective and which can use the already operational Queqiao-2 infrastructure.

NASA, by contrast, is deliberately trying something different: building a lunar marketplace through its Commercial Lunar Payload Services (CLPS) programme. The agency buys lunar delivery, mobility and technology services from companies that own and operate their own spacecraft.

NASA currently has 17 contracted deliveries carrying more than 60 instruments.

And the American effort has already yielded useful experience: Intuitive Machines’ IM-2 mission, Athena, attempted strikingly similar undertakings to Chang’e-7. It carried a drill and mass spectrometer looking for volatiles, a small hopping vehicle intended to explore difficult terrain and an experimental mobile communications network. However, the lander fell over at the landing site and was powered down just one day after arriving.

In essence, the destination dictates the problems; different space programmes are experimenting with different ways to resolve them.

Learning how to live on the Moon

Finding lunar resources is only the first step. Chang’e-7 will attempt to determine where useful lunar resources are found near the Moon’s South Pole and characterise their nature.

Chang’e-8, slated for potential launch in 2028, will move towards demonstrating how they might actually be used.

Crewed exploration will likely follow, culminating in the construction of the International Lunar Research Station, jointly led by the China National Space Administration and Russia’s Roscosmos space agency.

On the other side of the Pacific, the CLPS will feed technology and science into the broader NASA-led Artemis programme, which the agency explicitly describes as laying the foundation for sustained lunar exploration.

Ultimately, the lunar South Pole doesn’t care which flag is on a spacecraft. Any explorer entering its permanently shadowed craters faces the same darkness, severe cold, broken terrain and communications problems.

Getting to the Moon was one of the great technological challenges of the 20th century. Learning how to live and work there may be one of the great challenges of the 21st.

 

This article is republished from The Conversation under a Creative Commons license. Original article.

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How much ice is stored in the world’s glaciers? And where exactly is it located? A new study led by Ca’ Foscari University of Venice, in collaboration with the Institute of Polar Sciences of the National Research Council of Italy (CNR-ISP), provides an updated global map of glacier ice volume.

The study ¹ introduces IceBoost v2.0, a machine-learning model developed by Niccolò Maffezzoli, physicist and researcher at Ca’ Foscari University of Venice and affiliated with CNR-ISP. IceBoost v2.0 was trained on more than 7 million ice-thickness measurements collected from glaciers across the globe. The model combines these observations with 26 physical and geometrical variables (including topographic slope and curvature, ice velocity, and temperature) to reconstruct on a point-by-point basis the ice thickness, and thus the volume, of every glacier included in the Randolph Glacier Inventory (RGI), the world’s most up-to-date global glacier inventory, excluding the polar ice sheets.

An interactive web-app allows users to explore the data from Maffezzoli’s model for every glacier worldwide.

According to the new estimates, the world’s glaciers contain approximately 150,000 cubic kilometres of ice, equivalent to 32.3 centimetres of global mean sea-level rise if they were to melt completely (excluding Antarctica and Greenland). While this figure is consistent with previous global estimates, IceBoost v2.0 provides a far more realistic estimation of each glacier’s distribution, matching field observations up to 40% more accurately.

One of the most striking examples is the Geikie Plateau in eastern Greenland, where the glacier is up to 2 kilometres thick. In this area, IceBoost v2.0 estimates nearly twice as much ice as previously reported. “The distribution of glacier ice thickness is a fundamental variable for glaciological and climate models,” explains Niccolò Maffezzoli. “To predict how glaciers will evolve by 2100 and quantify their contribution to sea-level rise, we first need the most detailed possible picture of their current state. Researchers involved in the Glacier Model Intercomparison Project (GlacierMIP4), who are producing the next generation of glacier simulations to inform the IPCC’s assessments of glacier evolution through to 2100, will use IceBoost v2.0 as their sole representation of present-day situation.”

The new dataset also provides valuable guidance for future field campaigns and scientific investments. In fact, IceBoost v2.0 maps identify regions where model estimates are most reliable, as well as areas where additional observations are most urgently needed, including the Himalaya and the Karakoram ranges, and the major Patagonian ice fields. The research also has significant implications for freshwater management. Glaciers sustain rivers, ecosystems, agriculture, and local communities, supporting the livelihoods of around 1.9 billion people worldwide. Better estimates of glacier thickness and ice volume make it possible to produce more reliable projections of future freshwater availability, particularly in increasingly arid and desertifying regions such as parts of South America.

“Glaciers are highly complex systems. Although the governing physics is well understood, many of the parameters involved in the equations remain unknown, poorly constrained or  extremely difficult to measure,” Maffezzoli concludes. “Machine-learning models offer an alternative approach: they learn directly from data, generating predictions without imposing a predefined physical description. When sufficient data is available, this approach often proves highly effective. The future lies in hybrid models, where physical modelling and learning from experimental measurements work together to produce even more accurate estimates. We must move quickly: glaciers at mid-latitudes, including those in the Alps, are expected to disappear within the next few decades.”

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Arctic terrestrial permafrost ecosystems store around 1,300 gigatonnes of carbon from organic sources, such as from the remains of plants. Sediments in oceans and river deltas contain a further 400 gigatonnes. Global warming, however, is taking its toll on this natural freezer: temperatures in the Arctic are rising faster than anywhere else on our planet, with the result that permafrost in the region is thawing rapidly. The carbon stored here can then enter the Arctic Ocean via rivers and eroding coastlines. “Consequently, up to 0.02 gigatonnes are entering the sea each year, and according to forecasts, this outflow could rise by 70 to 150 per cent by the year 2100,” says Dr Manuel Ruben, lead author of the study from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). “However, how much of this is released back into the atmosphere as a greenhouse gas and how much is stored in the seabed has, until now, been largely unknown.” Yet, this knowledge is essential for assessing the climate impact of thawing permafrost.

To get to the bottom of this unknown, the researchers retrieved and analysed sediment cores taken at various intervals off the coast of the Canadian island of Herschel Island ¹. The cores contain deposits spanning around 50 years. Analysis of the sediments revealed something surprising: “Although the sea here carries away huge quantities of organic carbon from the coast, surprisingly little of it ends up in the ocean’s active carbon cycle,” says Manuel Ruben. “Microorganisms convert around ten per cent of the organic carbon from the sediments into gases, which rise into the water and can then enter our atmosphere.” The major share, however, is stored in the seabed.

In conducting their analysis, the researchers first examined the composition of the sediment cores in detail and also investigated how rapidly permafrost deposits accumulate on the seabed. To this end, they measured how much inorganic dissolved carbon accumulates in tiny cavities within the sediment layers – known as pore water. This provides an indication of how much CO₂ microorganisms have ‘exhaled’ after ‘digesting’ the organic carbon. The isotopic composition of the pore water provides insights into which organic material from which source has been broken down. ”Carbon isotopes represent our atomic indicators that can identify the food source of the microorganisms,” says Prof. Gesine Mollenhauer, a geochemist at the AWI and co-spokesperson for the ‘The Ocean Floor – Earth’s Unexplored Interface’ cluster of Excellence. “The ¹³C isotope, for example, tells us whether they have consumed carbon from land or from the sea. By way of the ¹⁴C isotope, we were able to determine whether the single-celled organisms preferred old organic carbon from permafrost or fresh organic carbon from algae remains.”

One explanation for this lies in the eating habits of these tiny organisms: “The sediment is home to ‘gourmet’ bacteria that apparently prefer fresh carbon stemming from, for example, more recent algal remains over the ‘old’ carbon from permafrost deposits,” explains Gesine Mollenhauer. This suggests that the organic carbon entering the sea from land contributes less to the amount of greenhouse gases in the atmosphere than originally feared. “However, we do need further research here. This is because some of the organic carbon from the permafrost may already have been broken down before it reaches the seabed.”

In addition to the impact of land-ocean carbon transport on atmospheric greenhouse gas levels, further effects are possible. For instance, this transport influences the biogeochemistry of coastal waters, which also play an important role in providing food for the local population. This is because the sediments alter the amount of sunlight available: on the one hand, the freshly broken-off fragments cloud the coastal ocean, while on the other hand, the organic carbon they contain discolours the water as it dissolves into it. Single-celled organisms such as algae, however, need light to convert this into biomass and oxygen. This primary production, in turn, forms the foundation for marine life such as fish, crustaceans and seals. The researchers aim to investigate these complex interrelationships, among other things, as part of the international ‘Arctic Pulse’ campaign planned for 2027. Through coordinated measurement campaigns aboard the Polarstern research icebreaker, using the AWI’s research aircraft and on land, they will investigate how rapid environmental change is altering ecosystems in the Arctic.

“Our study shows, more precisely than ever before, how much carbon is safely stored in the seabed – and just how much of the decomposed material actually originates from the old permafrost,” says Manuel Ruben. “This provides an important foundation for climate models that can predict the consequences of permafrost thawing for the global climate.”

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