Hydrocarbon sand and methane streams scientists have explained the landscapes of Titan

(ORDO NEWS) — From dunes to canyons, the variety of landforms on Saturn’s moon is astounding. Scientists have explained how soft organic dust “melts” into grains of sand and rocks, and how winds and rains form dunes and carve out canyons.

Titan, a moon of Saturn, is the only known body in the solar system besides Earth that has a seasonal fluid cycle. Scientists at Stanford and the Jet Propulsion Laboratory have shown how this fluid cycle, along with the sediment cycle, explains the diversity of Titan’s landscapes.

From a distance, Titan looks like Earth. It is surrounded by dunes at the equator, plains dominate in the middle latitudes, and lakes and canyons lie at the poles. Thanks to the cocoon from the dense atmosphere, it rains and winds blow. But instead of water, liquid methane flows on Titan, and the nitrogen wind collects dunes from hydrocarbon sand.

The mechanical properties of such sand are significantly different from the properties of the usual silicate sedimentary rocks that cover the Earth and Mars.

The main difference is that hydrocarbon particles are much less durable and must be quickly ground to dust, while relatively large granules are needed to form dunes. How do these simplest organic compounds maintain their size?

On Earth, under the influence of the forces of nature, silicate stones and minerals eventually break down into small particles. Wind and water currents carry these particles to the places of sedimentation, where under the action of pressure, groundwater and sometimes heat, the particles “melt” back into stones.

Scientists suggest that a similar cycle should exist on Titan. It is obvious that there, too, the forces of nature grind the rocks to the state of sand and dust. It is not clear how the dust again turns into stones and sand for the dunes.

Ooids, small spherical granules that are often found in the shallow waters of tropical seas, helped find the answer to this question. They are unique in that they are formed by chemical precipitation: calcium carbonate from water is deposited in layers on grains of ordinary sand.

The particles rub against each other, break down, calcium carbonate gets back into the water and settles again.

The processes of destruction and growth compensate each other, and the particles maintain their size. The researchers suggested that in the same way on Titan, dust particles “fuse” with each other, forming grains of sand and rocks, which are then ground down by the wind.

Hydrocarbon sand and methane streams scientists have explained the landscapes of Titan
Map of the migration of sedimentary rocks and the relief of Titan: highlands (gray), lakes and seas (blue), proposed river valleys (light blue), dunes (pink). Black arrows indicate the direction of rock migration through rivers. Red arrows indicate air flow. The landing point of the Huygens probe is marked with a red cross. Green – the planned landing point of the Dragonfly

Taking this hypothesis into account, the team of scientists modeled the sedimentary migration cycle based on climate and atmospheric data collected by the Cassini mission. It turned out that the process of “melting”, the pattern of winds and precipitation explains the diversity of landscapes.

The strongest winds blow in the equatorial belt, so sedimentary rocks there are constantly destroyed and form dunes.

In mid-latitudes, the wind is much weaker, but the humidity is higher, and the particles “melt” into dense rocks that form the plains. At the poles, rains and rivers carve deep canyons and labyrinths in the rocks. Their terrestrial analogue is karsts.

“Our overarching model allows us to understand how these sedimentary topography interact,” says Mathieu Lapôtre , a geologist at Stanford University.

“If we understand how these pieces of the puzzle fit together and their mechanics, then by studying the topography formed by these sedimentary processes, we can make assumptions about the climate and geological history of Titan and their impact on the likelihood of life on Titan.”

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