[X] My Assistant

[MichaelT]

I just read an interesting "hypothesis paper" by Pietro-Ballesteros et al. in the current issue of Astrobiology (2006, Vol. 6, No. 4: 651-667) . It proposes an explanation for the origin of the "dark spider" features in the high latitudes of southern Mars (see attached image, crop from MSSS MOC E1300006). According to the authors these features result from the seasonal melting of aqueous salty solutions.

The paper can freely be downloaded from this address: http://www.liebertonline.com/doi/pdfplus/1.../ast.2006.6.651

This is the abstract:

"Recent data from space missions reveal that there are ongoing climatic changes and erosive processes that continuously modify surface features of Mars. We have investigated the seasonal dynamics of a number of morphological features located at Inca City, a representative area at high southern latitude that has undergone seasonal processes. By integrating visual information from the Mars Orbiter Camera on board the Mars Global Surveyor and climatic cycles from a Mars' General Circulation Model, and considering the recently reported evidence for the presence of water-ice and aqueous precipitates on Mars, we propose that a number of the erosive features identified in Inca City, among them spiders, result from the seasonal melting of aqueous salty solutions."

Michael