Scoria Cones on Earth and Mars - EARTH/UNIVERSE

June 19, 2025 (Earth)

May 7, 2014 (Mars)

Since the 1970s, planetary geologists have known that volcanic features cover large swaths of Mars. Early Mariner 9 images revealed massive shield volcanoes and lava plains on a scale unlike anything on Earth. Olympus Mons, the tallest volcano in the solar system, stands nearly three times higher than Mount Everest. Alba Mons, the planet's widest volcano, spans a distance comparable to the length of the continental United States.

Both Olympus Mons and Alba Mons were primarily built by basaltic effusive eruptions—relatively calm outpourings of "runny" lavas that spread across the surface in sheets. This is thought to be the most common type of volcanism on Mars, accounting for the vast majority of its volcanic landforms. However, a small portion was produced by explosive volcanism of the sort that forms volcanic cones, pyroclastic flows, and ashfalls.

The dearth of explosive volcanic features on Mars has long puzzled geologists. With an average atmospheric pressure 160 times lower than Earth's and only a third of the gravity, explosive eruptions should theoretically occur more easily on the Red Planet, said Petr Brož, a planetary geologist with the Czech Academy of Sciences. That rarity is part of what makes features like the volcanic cones (shown above) found in Mars' Ulysses Colles region so compelling to planetary geologists.

"They appear to be scoria cones—a clear sign of explosive volcanism," Brož added. "They were the first identified in the Tharsis region in the 2010s, and they helped paint a broader and more complete picture of Martian volcanism."

The CTX (Context Camera) on NASA's Mars Reconnaissance Orbiter captured this image (second image above) of Ulysses Colles above on May 7, 2014. Ulysses Colles is located at the southern edge of Ulysses Fossae, a group of troughs within the Tharsis volcanic region.

The OLI (Operational Land Imager) on Landsat 8 captured an image with similar cones in the San Francisco Volcanic Field (SFVF) in northern Arizona on June 19, 2025 (top). Planetary geologists consider the cones in the two locations to be highly analogous. Both images also include grabens—linear blocks of crust that have shifted downward.

In both images, the scoria cones appear as rounded hills crowned with circular vents, while lava flows spread outward as dark, textured areas around the bases of the cones. At both locations, seemingly younger and smaller lava flows appear to spill from some cones, while older, more weathered flows lie in the background. 

"Understanding similar features on Earth helps us know what to look for on Mars and interpret processes that we can’t observe directly," said Patrick Whelley, a NASA volcanologist who is part of a team that develops field equipment and techniques for Moon and Mars exploration.

SP Crater (above left), located in Arizona’s San Francisco Volcanic Field, features a 7-kilometer-long lava flow that extends northward and has been used for NASA astronaut geology training. In two places, the flow has spilled into a graben, creating a distinctive half-moon pattern along its left side.

On Earth, scoria cones form when gas-rich magmas soar high into the air and solidify into small particles of material called scoria that accumulate in steep-sided structures. While similar processes create cones on Earth and Mars, there are important differences. Martian scoria cones are typically taller, wider, and have gentler slopes, Flynn said. That makes sense. With lower gravity and atmospheric pressure, volcanic fountains can loft erupted magma higher and farther from the vent, producing larger cones.

There are far more scoria cones on Earth, where tens of thousands exist and account for about 90 percent of volcanoes on land. On Mars, "we have only identified tens to a few hundred candidates," Broz said. It could be that explosive volcanism was never common on Mars, or it could be that it was but that explosive features have been covered up by younger, effusive flows or destroyed by erosion, he added.   

Whelley noted that on Mars, it remains unclear whether the Martian lava flows or the scoria cones formed first. The lava flow could be older, with the cone forming on top. Or, the cone may have formed first and later become plugged, forcing lava to spill from its side. Determining the order of events is one of the "puzzles of geology" that planetary geologists try to solve when studying Martian features remotely, he said. "Visiting places like the San Francisco Volcanic Field and studying the geology of analogous features up close on Earth helps us know what clues to look for when interpreting Martian geology."

Below (left) is a closer view of a scoria cone on Earth, southeast of SP Crater, called Sunset Crater. It erupted about 800 years ago, making it the youngest scoria cone in the San Francisco Volcanic Field. The analogous cone in Ulysses Colles (right), in contrast, is thought to be billions of years old.

Note that eruptions that create scoria cones are "mildly explosive," usually Strombolian events, characterized by intermittent lava fountains, said Ian Flynn, a planetary geologist at the University of Pittsburgh. They differ from the far more violent explosive eruptions that send ash columns billowing tens of kilometers into the air, as happened at Hunga Tonga-Hunga Ha'apai in the South Pacific, he added.

Mars also shows evidence of highly explosive "super eruptions," but that type of eruption leaves behind a different geologic signature: large depressions called paterae and broad, thin deposits of ash and other erodible material sculpted into landforms such as yardangs.

Planetary comparison is valuable for understanding the geology of distant worlds, Brož said. Without such comparisons, it becomes harder to determine how landforms on other planets or moons may have formed at all.

But caution is essential. "In planetary science, it's often said—only half-jokingly—that even if something looks like a duck, behaves like a duck, and sounds like a duck, it may not actually be a duck," he added. It's easy, for instance, to confuse scoria cones with mud volcanoes.

Researchers are highly confident that the Ulysses Colles cones formed through explosive volcanism based on the surrounding volcanic landscape, but in more ambiguous terrain it can be difficult to tell. Mars is fundamentally different from Earth, he cautioned. Brož's laboratory research suggests, for instance, that mud flows on Mars can look much like certain types of lava flows, and that, under certain conditions, they can even boil and levitate. "We also have to avoid being constrained by terrestrial experience," he said. "If we fail to think outside the box, we may overlook important possibilities."

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey and CTX data from the Mars Reconnaissance Orbiter. Story by Adam Voiland.  

Source: Scoria Cones on Earth and Mars - NASA Science

Plant cell structure could hold key to cancer therapies and improved crops - Biology - Plants & Animals - Molecular & Computational biology

Professor Bo Liu, Department of Plant Biology, holds an Arabidopsis plant while Professor Jawdat Al-Bassam, Department of Molecular and Cellular Biology, holds a model of the augmin protein complex. Liu and Al-Bassam have worked out the structure of the augmin complex, which plays a vital role in maintaining the protein skeleton in both plant and animal cells. This could have applications both in human cancer and infertility, and in breeding new varieties of crop plants. Credit: Joaquin Benitez, UC Davis

Can the bend of a banana give us insight into cancer? What does the shape of a rice grain have to do with infertility? The proteins that give plants their shape and structure are also involved in human disease. A team led by researchers at the University of California, Davis, has mapped out the structure of a key player, augmin, in exhaustive detail. Their work is published in the journal Nature Communications.

"This work shows how plants and animals are similar," said Jawdat Al-Bassam, associate professor of molecular and cellular biology at UC Davis. "It could help answer some fundamental questions not just about plants, but also humans."

Augmin is a protein complex that binds to microtubules, the cell's internal skeleton, aiding in the formation of branched microtubules and playing a key role in cell division.

Augmin defects can cause infertility in humans. In addition, "Some augmin subunits are highly expressed in human cancer cells," said Bo Liu, a professor of plant biology who collaborated with Al-Bassam on the new study. Understanding its structure could yield both new medical treatments and new strategies for breeding higher-quality rice and cotton crops.

A surprise in plants

Inside the cells of every plant and animal is a shape-shifting skeleton.

This morphing skeleton can cause cells to expand, stretch, or bend—sculpting the overall shapes of bulging strawberries, curving cucumbers, and the long skinny nerve cells that connect our brains and feet.

When a cell divides, its protein skeleton grows long arms that reach out and grasp the DNA-containing chromosomes. The arms then shorten, pulling the chromosomes apart, and ensuring that each daughter cell receives a complete set of genes.

A cell's skeleton assembles from tiny protein blocks called tubulin. The tubulin snaps together, creating hollow rods called microtubules. These microtubules form the arms of a bigger structure, called the spindle, which delicately separates the chromosomes when a cell divides.

In 2007, scientists found that animal cells could not form a functioning spindle if they lacked the augmin protein complex. Without it, the microtubules could not branch, spindle arms were weak and flimsy, and the cells often died during division.

"Most people did not think augmin was also in plants," Liu said. But, in 2011, he and his students discovered a set of eight augmin genes in Arabidopsis thaliana, a plant in the mustard family often used in genetic research. Those plant genes encode a protein complex whose overall structure is very similar to human augmin.

Cellular scaffolds, cotton and rice

Liu discovered that plant augmin doesn't just assist cell division, as it does in animals; it also regulates the shapes of plant cells.

As a plant cell grows, a scaffold of microtubules expands within it. That scaffold positions enzymes at the growing edges of the cell, allowing them to expand the rigid cellulose wall that surrounds a plant cell.

When Liu reduced a cell's production of augmin, its scaffold became flimsy and disorganized.

"Microtubules guide the growth of cells," he said.

This microtubule scaffold is critical for plant survival; oryzalin, an herbicide frequently used on farms, kills plants by interfering with it.

The scaffolding also shapes important traits in crop plants. The juice in oranges is contained in gigantic cells whose dramatic ballooning is driven by a microtubule skeleton that expands inside each cell. Long-grained rice owes its shape to the microtubule scaffolds that cause individual cells to elongate. It's also important in cotton, whose fiber cells begin the size of a red blood cell and then extend, driven by telescoping microtubules.

"It's pretty dramatic," Liu said. "They lengthen by thousands of times."

Even as Liu pieced together the function of plant augmin, he knew almost nothing about how it physically initiates branches in microtubules. So, he collaborated with Al-Bassam, who worked upstairs in the same building, and who specializes in protein structures.

A molecular pitchfork

Md Ashaduzzaman, a postdoctoral fellow in Al-Bassam's lab, cooled plant augmin proteins to -196° C and took thousands of electron microscope images—an approach called CryoEM. He and Al-Bassam spent months assembling the data into a single structure.

Their job was akin to that of someone who had never seen the Eiffel Tower mapping its overall structure by piecing together thousands of up-close photos.

They finally succeeded in unveiling the mystery structure.

"Augmin turns out to look like a pitchfork," said Al-Bassam. He and Ashaduzzaman worked out how the pieces come together to form the complete augmin complex. They identified the critical structures that it uses to attach to microtubules and form branches.

Seeing the nuanced differences between the plant and animal versions of augmin could improve our understanding of how it works on both sides.

In humans, altered levels of augmin protein are associated with a worse prognosis in certain cancers of the liver, brain and other organs. Understanding how augmin functions—or malfunctions—could illuminate new ways to treat these cancers. It could also help identify the unknown causes of infertility in some people.

Meanwhile, understanding how augmin functions in plants could help scientists breed new varieties of important California crops, such as plums and strawberries.

For Al-Bassam, it's a fulfilling outcome.

"This was a very long endeavor," he said. "It was a real labor of love that required a lot of people working together." 

Provided by UC Davis 

by Douglas Fox, UC Davis

edited by Stephanie Baum, reviewed by Robert Egan 

Source: Plant cell structure could hold key to cancer therapies and improved crops