Patterns in Mars crater floors give picture of drying lakes

Patterns in Mars crater floors give picture of drying lakes
Desiccation patterns on Earth (left) and Mars (right). Credit: Google/NASA/JPL


The polygons are formed when long cracks in the surface of the martian soil intersect.  El Marry investigated networks of cracks inside 266 impact basins across the surface of and observed polygons reaching up to 250 metres in diameter.  Polygonal troughs have been imaged by several recent missions but, until now, they have been attributed to thermal contractions in the martian permafrost.  El Maarry created an analytical model to determine the depth and spacing of cracks caused by stresses building up through cooling in the martian soil.  He found that polygons caused by thermal contraction could have a maximum diameter of only about 65 metres, much smaller than the troughs he was seeing in the craters.


Patterns in Mars crater floors give picture of drying lakes

El Maarry identified the crater floor polygons using images taken by the MOC camera on Mars Global Surveyor and the HiRISE and Context cameras on Mars Reconnaissance Orbiter.  The polygons in El Maarry’s survey had an average diameter of between 70 and 140 metres, with the width of the actual cracks ranging between 1 and 10 metres.



Source: Europlanet

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Citation: Patterns in Mars crater floors give picture of drying lakes (2009, September 16) retrieved 3 August 2021 from https://phys.org/news/2009-09-patterns-mars-crater-floors-picture.html

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