Geology Found by Mars Rover at Ancient Hot Spring Deposit Resembles Earth Biosignatures

http://www.nature.com/articles/ncomms13554#abstract

The authors (at Arizona State University) say:

"The morphology of HomePlate [the Martian site] digitate silica structures bears a strong resemblance to the microbially mediated microstromatolites at El Tatio [a Chilean desert comparison site]."

But they go on to say,

"However, determining the relative contribution of biotic and abiotic influences in the formation of a particular stromatolite can be quite difficult and must be assessed on a case-by-case basis. Entirely abiogenic internally laminated columnar structures have been synthesized via numerical modeling and laboratory spray paint deposition experiments, complicating the effort to interpret such structures in the pre-Cambrian rock record on Earth."