These meteorites are interpreted as Martian because they have elemental and isotopic compositions that are similar to rocks and atmospheric gases on Mars, which have been measured by orbiting spacecraft, surface landers and rovers.

Several scientists suggested these characteristics implied the origin of SNC meteorites from a relatively large parent body, possibly Mars.

In 2000, an article by Treiman, Gleason and Bogard gave a survey of all the arguments used to conclude the SNC meteorites (of which 14 had been found at the time) were from Mars.

[13] These two classification systems do not line up with each other, hinting at complex relationships between the various source rocks and magmas from which the shergottites formed.

[18][19] Nakhlites are named after the first of them, the Nakhla meteorite, which fell in El-Nakhla, Alexandria, Egypt in 1911 and had an estimated weight of 10 kg.

Their crystallization ages, compared to a crater count chronology of different regions on Mars, suggest the nakhlites formed on the large volcanic construct of either Tharsis, Elysium, or Syrtis Major Planum.

NWA 2737 was found in Morocco or Western Sahara in August 2000 by meteorite hunters Bruno Fectay and Carine Bidaut, who gave it the temporary name "Diderot."

It was shown by Beck et al.[22] that its "mineralogy, major and trace element chemistry as well as oxygen isotopes revealed an unambiguous Martian origin and strong affinities with Chassigny."

This meteorite received much attention after an electron microscope revealed structures that were considered to be the fossilized remains of bacteria-like lifeforms.

[citation needed] In March 2004 it was suggested that the unique Kaidun meteorite, which landed in Yemen on December 3, 1980,[23] may have originated on the Martian moon of Phobos.

The young formation ages of Martian meteorites was one of the early recognized characteristics that suggested their origin from a planetary body such as Mars.

All nakhlites, as well as Chassigny and NWA 2737, give similar if not identical formation ages around 1300 Ma, as determined by various radiometric dating techniques.

[17] The amount of time spent in transit from Mars to Earth can be estimated by measurements of the effect of cosmic radiation on the meteorites, particularly on isotope ratios of noble gases.

There are also small ovoid and tubular structures that might be nanobacteria fossils in carbonate material in crack fills (investigators McKay, Gibson, Thomas-Keprta, Zare).

[38] Micropaleontologist Schopf, who described several important terrestrial bacterial assemblages, examined ALH 84001 and opined that the structures are too small to be Earthly bacteria and don't look especially like lifeforms to him.

The study, published in the journal of the Geochemical and Meteoritic Society, used more advanced high resolution electron microscopy than was possible in 1996.

[46] Other signs of surface liquid water on Mars (such as recurring slope lineae[47]) are a topic of debate among planetary scientists, but generally consistent with the earlier evidence provided by Martian meteorites.