Geological Activity Detected in the Venus Mantle

The slow churning of Mantle of Venus beneath the surface may blame for much of the brittle upper crust of Venus being split into fragments that shudder and move. My colleagues and I discovered this by examining how the surface of Venus interacts with the planet’s innards using decades-old radar data. We describe it in a new study published on June 21, 2021, in the Proceedings of the National Academy of Sciences.

Venus possesses a profusion of tectonic landforms, as planetary scientists like me have long known. Long, thin belts of crust have been forced together to form ridges or pulled apart to generate troughs and grooves in some of these formations. There’s evidence that portions of the crust have shifted side to side in many of these belts.

For the first time, our new research reveals that these bands of ridges and troughs frequently mark the boundaries of flat, low-lying areas with slight deformation themselves and that they are individual blocks of Venus’ crust that have shifted, rotated, and slid past each other over time – and may have done so recently. It resembles pack ice that floats on top of the ocean and is similar to Earth’s plate tectonics on a lesser scale.

Like Earth’s, the Mantle of Venus is thought to whirl with currents when it is heated from below, according to scientists. My colleagues and I recreated Venus’ slow but intense Mantle movement, demonstrating that it is powerful enough to fracture the upper crust everywhere we’ve discovered these lowland blocks.However, no trip to Venus has yet definitively demonstrated that the planet is active. There’s enticing but ultimately inconclusive evidence that volcanic eruptions have occurred there in the geologically recent past — and possibly now are. The case for tectonic activity, which involves the cracking, breaking, and folding the planet’s crust, is considerably weaker.