Mars has long been known for its dusty red dunes, towering volcanoes, and deep canyons, but recent high-resolution images from NASA’s Mars Reconnaissance Orbiter (MRO) have revealed something far more unearthly. Scattered across the southern polar region, scientists have identified strange, spider-like formations, massive dark splotches, and high-velocity geysers erupting from beneath the surface—features unlike anything found on Earth. These formations are part of a seasonal process unique to Mars, driven by carbon dioxide (CO2) sublimation rather than the wind and water erosion shaping landscapes on Earth.
During Martian spring, as temperatures rise, CO2 trapped beneath the surface is violently released, carving out eerie, web-like channels and sending bursts of dark material across the planet’s icy surface. For years, scientists have been puzzled by these bizarre formations, but recent studies indicate they could offer new insights about the unique processes governing Martian geology.
One of the most puzzling discoveries is the "araneiform terrain," known as "Martian spiders." These formations consist of branching channels resembling giant alien spider webs spread across the southern polar ice cap. Unlike Earth, where erosion is primarily caused by water, wind, and plate tectonics, the spider formations are created by carbon dioxide gas trapped beneath ice sheets. According to Lauren McKeown, a planetary scientist at NASA’s Jet Propulsion Laboratory (JPL), these formations are among the most peculiar geological features ever observed on another planet. She described them as "strange, beautiful geologic features" highlighting their uniqueness.
The dynamics at work are fascinating. A thick slab of CO2 ice builds up during the Martian winter, sealing off gas below. When sunlight warms the surface, this gas builds pressure until it ruptures through the ice layer, shooting sand and dust high above the surface. This active geological process suggests Mars is anything but static; it might have active seasons reshaping its surface.
Alongside the spider terrain, Mars is also home to many mysterious dark spots and geysers appearing annually during the ice cap’s thaw. These CO2 explosions release plumes of dark sediment, creating landscapes reminiscent of ink stains against the white background of the polar regions. Scientists propose mechanisms to explain these eruptions, asserting they reveal how the Martian atmosphere and geology interact with each other.
This has exciting ramifications for future Mars exploration. The discovery of geysers and spider terrain suggests interactions between Martian geology and its atmosphere play significant roles, potentially impacting future missions. Researchers are considering how knowledge of CO2 behavior and subsurface activity can aid mission architects striving to establish human habitats on Mars.
Meanwhile, on Earth, researchers have made groundbreaking discoveries about our planet’s complicated inner structure with significant implications for our knowledge of geology. Recent investigations revealed enormous unmixed regions, or "supercontinents," buried thousands of kilometers below the crust. These hidden structures, one under Africa and the other beneath the Pacific Ocean, may have far-reaching impacts on mantle activity and our planet's plate tectonics.
Utilizing insights obtained from seismic data, scientists have gathered information about the composition and age of these mysterious mantle regions, demonstrating they constitute about 20% of the mantle-core boundary. Lead researcher Dr. Sujania Talavera-Soza points out these regions might serve as anchors influencing mantle flow and tectonic activity above, affecting surface phenomena such as earthquakes and volcanic eruptions.
Prior studies identified these regions based on how seismic waves slowed down when encountering the supercontinents, which hinted at their hotter nature compared to surrounding materials. Still, their precise structural makeup remained speculative until this new analysis revealed the zones’ mineral formations. This knowledge shapes our comprehension of mantle convection and provides insights about geological phenomena on Earth's surface.
The supercontinents, intriguingly identified as large low shear velocity provinces (LLSVPs), appear older than previously estimated, with studies implying they might have existed for at least half a billion years. Their durability suggests they have weathered the dynamic pressures of mantle convection, remaining largely stagnant within Earth’s tumultuous interior.
The discoveries challenge existing paradigms of planetary geology, demonstrating both Mars and Earth exhibit mechanisms responsible for geological transformation distinct from what was assumed. On Mars, the alien process of CO2 sublimation redefines our grasp of its surface activity, and on Earth, the age and role of supercontinents add complexity to the mantle dynamics.
Looking toward the future, researchers express optimism about deepening our knowledge of both planets. Mars continues to intrigue with evidence of compelling geological activity conducive to questions surrounding life's potential. Simultaneously, Earth's hidden structures present researchers with mysteries capable of transforming geological theory, giving us insights not just about our planet's history but its geological future as well.