Amazing stuff! This was discovered on NASA images from the 1990s? What took so long?
Do we need a new Venus mission?
"... New research shows our planetary neighbor may be less dormant than thought. Scientists reanalyzed rift valleys on Venus’s surface, which are low-lying regions formed as the crust pulls apart or due to volcanic activity. On Venus, rift valleys can span as long as 10,000 kilometers ...
High-resolution computer models of the underlying geological processes revealed that broad ridges called rift flanks form at the valleys’ edges when they are either young or still forming. Soon after, the rift flanks widen and flatten as Venus’s crust relaxes. When the researchers looked at images of the venusian surface taken by NASA’s Magellan spacecraft in the 1990s, wide, high flanks were visible. The features indicate that the surface was active somewhat recently—and the world is far from dead. ..."
"In brief
- ETH researchers have developed innovative computer models to study the rift valley systems on Venus.
- The simulations indicate that recently formed rift valleys feature high, broad flanks, whereas older valleys tend to subside and are less elevated.
- The new findings can help us identify geologically active regions that require particularly close examination for future Venus missions.
..."
From the abstract:
"Rifts are prominent tectonic features on Venus, yet their formation, evolution and tectonic activity remain debatable.
Here we conducted 3D numerical thermomechanical experiments with visco-elasto-plastic compressible rock rheology to systematically investigate the rifting dynamics and topography under Venusian conditions. To compare active and inactive rift morphologies, the relaxation of rift topography after extension ceases was also investigated.
Our modelling results suggest a relatively thick thermal lithosphere and a strong crust with dry diabase or mafic granulite rheology in rifted regions and demonstrate that wide rift flank uplifts strongly indicate either presently ongoing Venusian rifting or activity within the past few tens of millions of years.
The rift valleys in the Ganis, Dali and Devana Chasmata have wide rift flank uplifts, and their characteristic topographic features are comparable to the modelled early-stage active rifts undergoing relatively high extension rates of 3−10 cm yr−1.
This suggests that the Venus rifts in these regions are still active or were active very recently. Their morphology also indicates faster extension rates than commonly assumed for Venusian rifting, potentially associated with recent vigorous mantle plume activity."
Venus: Dead? Far from it (original news release) "Simulations conducted by researchers at ETH Zurich suggest a strong likelihood that Venus’s rift valleys are still geologically active rather than being mere relics of a bygone era, as had been previously believed. This finding reshapes our understanding of Earth’s sister planet and will influence future missions to Venus. "
There are huge rift valleys on Venus. They suggest that the planet is still geologically active.
No comments:
Post a Comment