Thursday, 22 October 2015

The Martian Files: Geological Activity

Formation
Mars (Valles Marineris on the centre)
Mars was created 4,600 million years ago, like the rest of the Solar System. At the beginning the Solar System was a concentration of interstellar dust and hydrogen gas, known as Solar Nebula. After the primitive Solar Nebula, Mars (and the rest of the planets) began to form by the accretion of small dust particles, sand, rocks and asteroids in the early solar system. The energy from this collisions and impacts started generating heat, creating a molten core and being the fuel of future volcanic activity. Mars was heavily bombarded by meteors. These, left craters and basins on its surface. Lava from volcanic eruptions filled the basins and the mixture of gases created the atmosphere.

Past geological activity
Volcanic activity:
Mars has the largest shield volcanoes in the solar system and has a wide range of other volcanic features. These include large volcanic cones, mare-like volcanic plains etc. However, volcanic features are not common, there are less than 20 named volcanoes on Mars. As mentioned before, volcanic activity had an important role in the formation of the planet.
Tectonics:
Evidence for plate tectonics (Valles Marineris)
There is much evidence that Mars is at a primitive stage of plate tectonics. On a huge canyon system known as Valles Marineris, the shell is broken and is moving horizontally over a long distance. This led to scientists to the conclusion that Mars has a mobile crust divided into two plates. The reason why Mars has less plates than Earth is that Mars’ shell is only slightly broken because the pace of movement of the plates is small and there is less thermal energy.
Marsquakes:
There is no definitive proof of marsquakes, but it is thought that they occur every million years due to the slow movement of the tectonics and the lack of thermal energy.
Erosion:
All mars is massively eroded. When volcanic eruptions occurred, water was released together with gases and lava. This water swept the rocks and sand while creating channels and basins. Lava, wind and ice have also eroded Mars, but the effect is not as huge as past current of water.
Sedimentation:
Photos of Mars have shown thick layers of rock within craters and other depressions, this evidence indicate that they may have formed in lakes or shallow seas. There have also been found some sedimentary structures on Mars that are very similar to those formed by microbes on Earth.
Magnetic field:
Large areas of magnetic materials have been found on Mars, which indicates that there once was a magnetic field on Mars.

Present geological activity
Nowadays, all the volcanoes on Mars are dormant, but there may be volcanic activity again in the future.
If the conclusions about plate tectonics were real, this would mean that with time the plates would move faster and the sell of Mars could break more creating more tectonic activity.
There are still some factors like wind and ice that can erode Mars, but as all water is frozen, the massive erosion generated by water on Mars in the past is no longer a reality. But some evidence for small salty water flows have been found recently.
Mars probably had a magnetic field but in the present, the magnetic field has disappeared.


By Sergio Alberca, Juan Carlos Blanco, Daniel Hernanz and Javier Verde.

Sources

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