I’m not sure if the NASA Viking mission did remote testing of Martian rocks. It may have only analyzed its atmosphere remotely and then matched it chemically to gases trapped within meteorites found on Earth.
“...unheralded measurement by the two NASA Viking spacecraft that landed on Mars in 1976. Although sent to conduct experiments to detect extant life in Martian soil (which they did not), the Viking landers gained redemption of sorts because the instruments measured the amounts of different gases in the thin Martian atmosphere. Those same gases were first found in 1983 by Donald Bogard and Pratt Johnson in very small amounts (but in the exact same proportions) trapped within shock glass veins and pockets in shergottite Elephant Moraine 79001, and now in at least five other Martian meteorites [on Earth].”
http://www.imca.cc/mars/martian-meteorites.htm
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From NASA:
“Why are they from Mars?
The 31 meteorites are unusual igneous meteorites (SNC achondrites named Shergotty, Nakhla, Chassigny are type examples). Most martian meteorites are 1.3 billion years old or less, much younger than typical igneous meteorites from asteroids which are 4.5 billion years old. They also have higher contents of volatiles than igneous meteorites. The conclusive evidence that the SNC meteorites originated on Mars comes from the measurement of gases trapped in one meteorite’s interior. The trapped gases match those that Viking measured in the martian atmosphere.”
http://curator.jsc.nasa.gov/antmet/marsmets/index.cfm
OK, here’s where they reach a shaky conclusion: “The conclusive evidence that the SNC meteorites originated on Mars comes from the measurement of gases trapped in one meteorite’s interior. The trapped gases match those that Viking measured in the martian atmosphere.”
That only “proves” the gases match. For ONE meteorite. hmmm is THAT good science?
It enables a fun hypothesis, NOT a conclusion.
Still it would be nice to GO to MARS and prove/dis-prove all this.
“In 1983 it was suggested by Smith et al. [3] that meteorites in the so called SNC group (Shergottites, Nakhlites, Chassignites) originated from Mars, from evidence from an instrumental and radiochemical neutron activation analysis of the meteorites. They found that the SNC meteorites possess chemical, isotopic, and petrologic features consistent with data available from Mars at the time, findings further confirmed by Treiman et al. [4] a few years later, by similar methods. Then in late 1983, Bogard et al. [5] showed that the isotopic concentrations of various noble gases of some of the shergottites were consistent with the observations of the atmosphere of Mars made by the Viking spacecraft in the mid-to-late 1970s.
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. They wrote, “There seems little likelihood that the SNCs are not from Mars. If they were from another planetary body, it would have to be substantially identical to Mars as it now is understood.”[6]
Composition
33 of the 34 Mars meteorites are divided into three rare groups of achondritic (stony) meteorites: shergottites (24), nakhlites (7), and chassignites (2), with the oddball meteorite ALH 84001 not usually placed in a group.[1] Consequently, Mars meteorites as a whole are sometimes referred to as the SNC group. They have isotope ratios that are said to be consistent with each other and inconsistent with the Earth. The names derive from the location of where the first meteorite of their type was discovered.”
http://en.wikipedia.org/wiki/Mars_meteorite