Science Special - Have NASA discovered evidence of life on Mars

I have always had a deep interest in the space programs of various nations, especially NASA. Of particular interest has been the activities of the Mars Rovers, which have been roaming the surface for years, sending back all manner of fascinating pictures. These are all logged for public interest on the NASA website. There are countless examples on various conspiracy sites, showing all manner of object that could be interpreted as evidence of intelligent life and former civilisations. Most of these are quite interesting, but most are, shall we say, not really very compelling.

If I am bored I'll have a look at these, seeing what people are working themselves into a froth about this week. Last night, however, I came across one that really does defy any explanation as to what it could be. If I was shown a picture of this in a desert on Earth, I'd say it was either a plant or a grave marking. I really can't see any explanation fo it being a geological feature. If you have any suggestions, I'd be keen to hear them.

Close up from NASA rover image

Have a look at the original picture on the NASA website here - 

https://mars.jpl.nasa.gov/msl/multimedia/raw/?rawid=1450MR0071820060703167E01_DXXX&s=1450.58131296153

The picture was taken by the Rover on 2016-09-04 01:15:16 UTC
I'm quite surprised that there hasn't been more comment. To me it looks like an old wooden cross with lichens growing on it, with a ring of stones. Whatever it may be, I find it fascinating