The Arctic could help probe Europa’s sub-ice ocean

It’s been two years since it ended MOSAiC Shipping, during which, among other things, the active hydrothermal vents of the Arctic region were examined. Since such hot water horns are found in all ocean basins, it was not really surprising that these hot water horns were also found deep in the Arctic Ocean, on the Gakkel Ridge, which is our slowest expanding oceanic ridge. planet. However, they are still very difficult to study due to year-round ice cover. Traces of these trumpets first in 2001 were found, so 9 places were identified, one of which is Aurora located on the side of a submarine volcano called One of 2014, then 2019-20. during the MOSAiC expedition, this volcano at a depth of 3,850 meters and its surroundings were measured in more detail.

“While every chimney discovery in the Arctic Ocean is a priority, we thought that what we had just found was one of the dullest places of its kind,” explained Chris German, the Woods Hole Oceanographic Institute (WHOI) researcher, a Nature communications lead author of a journal study on the site’s discovery in 2014. “When we got home, we thought, OK, it’s great that we’ve discovered a place in the Arctic, but if you take the ice sheet off its surface, it’s just like anywhere else.”

However, in the 2019 expedition, the area was visited again, as analysis of the available data showed the environment of the seamount Aurora in a new light. Today, German and his fellow researchers believe they’ve stumbled upon something very strange. On the one hand, this site and other similar areas of the Gakkel Ridge help to understand the functioning of ultra-slowly expanding ocean basins (in this case at a rate of 0.7-1.4 cm per year), and on the other , a make a true estimate of the amount of mineral resources (copper and gold) under the sea that they also contribute, and thirdly, they can help the search for extraterrestrial life as a natural laboratory.

For most mid-ocean ridges, the rate of expansion is much higher than this, e.g. The distance between Europe and North America will increase by 2.5 centimeters per year, and there are also areas in the Pacific Ocean that are expanding at a rate of 10-20 centimeters per year. Until now, it was thought that significant mineral deposits could not develop on slow-moving ridges like the Gakkel, because the hydrothermal circulation cannot survive long enough in this geological environment. Now, however, they have come to the conclusion that the hydrothermal system has been working very well for a long time, and as a result, mineral-rich areas are created in these places as well.

From the point of view of the study of organic substances and extraterrestrial life, it is important that in the hydrothermal area it is possible to study well the chemical processes during which the organic substances necessary for life are formed. This location will provide an excellent preparation opportunity for expeditions to explore the ocean beneath the ice crust of Jupiter’s moon Europa or Saturn’s moon Enceladus.

In the case of the Aurora hydrothermal field, the locality has a particularity. While in the case of the hundreds of similar areas already known, the hot water passes through the silicon-rich basalt, here the ultramafic rock forms the basis of the system. The composition of these primitive low-silicon rocks from deep within the Earth is similar to that of meteorites in many ways. Hot water solutions seeping through ultramafic rocks are also hypothesized to play a role in the formation of the sub-ice oceans of distant celestial bodies. This special location makes the Aurora Hydrothermal Field an excellent test site for investigating conditions believed to be similar on distant celestial bodies.