Hawaii’s Kilauea is the most active volcano in the world. Erupting continuously since 1983, it has created a cornucopia of beautiful alien features, from overflowing lava lakes and waterfalls to anastomosing rivers of lava at the surface and the dragon-like lava tubes snaking through the ground beneath them.
Once upon a time, Mars was a lot like Kilauea – a volcanic landscape with a grand mosaic of strange hellish features. Now, thanks to a new series of NASA images, scientists think that they’ve spotted some ancient lava waterfalls draped across the surface of the Red Planet.
Unlike Kilauea, Mars is no longer volcanically active, so these waterfalls aren’t fresh ones. Rather, they’re frozen monuments to an age of fire long past – and they’re huge.
Snapped by the Mars Reconnaissance Orbiter (MRO), these lava drapes are spread out across the rims of a volcanic crater 30 kilometers (18.6 miles) across. So how did they form?
This crater, found in the once highly active Tharsis region, initially looks like it could have contained a lava lake similar to the one at the heart of Kilauea: a bubbling mass of molten rock that is continually churning, listing, rising, and falling.
When the hotspot beneath lava lakes manages to melt more of the upper crust than usual, the lava lake sometimes rises up to such a height that it overflows and cascades down the crater rim. This can be seen on a semi-regular basis on Hawaii, and perhaps the same phenomenon happened on Mars.
However, in this case, the lava is doing something weird. It’s actually coming from outside the crater and surrounding it. At some point, the lava flow was so extensive that it ran up the crater slopes and cascaded down into it.
As the lava breached the crater rim, it encountered a series of rocky “steps” created by previous periodic eruptive episodes. This meant that the lava flow you can see here essentially moved down a volcanic staircase, a bit like pouring fresh glaze over a multi-tiered cake. Its extent has earned this aesthetically pleasing feature a new moniker by NASA – the “Niagara Falls of Mars”.
Although active for billions of years, the heat sources at the heart of Mars – its primordial heat left over from its formation and the heat released by radioactive elements – were extinguished, and these huge lava flows were no more. It’s a shame, really, because Mars once had some seriously cool volcanoes.
Its lack of plate tectonics meant that its gigantic hotspots produced the most massive volcanoes in the Solar System, and there was once an eruption so extensive that it caused the planet to tip over on its axis by 20°.