NASA says that Curiosity’s latest discovery, named "Jake Matijevic" in honor of a famed NASA engineer who died a few days after Curiosity landed on Mars back in March, is unique and is nothing like any previously examined Mars rocks. To put that in perspective, over the years, previous unmanned missions to Mars have examined Martian rocks numbered in the hundreds, reports The Seattle Times
When the NASA team guiding their robot explorer Curiosity picked on ‘Jake’ they had expected a ‘simple and uniform’ rock for analysis as part of a control to compare data from two chemistry experiments.
What has intrigued scientists is Jake’s unexpected composition, reports French website 20minutes
. Jake was the first rock which Curiosity’s arm-mounted Alpha Particle X-Ray Spectrometer (APXS) had analysed. Curiosity has already examined around 30 rocks on its mission using the robot’s Chemistry and Camera (ChemCam) instrument.
Commenting on the latest discovery, Edward Stolper of the California Institute of Technology in Pasadena, a Curiosity co-investigator, outlined its significance, “"This rock is a close match in chemical composition to an unusual but well-known type of igneous rock found in many volcanic provinces on Earth. With only one Martian rock of this type, it is difficult to know whether the same processes were involved, but it is a reasonable place to start thinking about its origin."
Ashwin Vasavada, Curiosity’s deputy project scientist, explained why the rock was intriguing NASA scientists, "Our laser instrument saw a slightly different composition at every point it analyzed."
Vasavada said although there was "broad agreement between it and another spectrometer that the robotic arm held against the rock, there also are some discrepancies yet to be understood. The differences between the two instruments are telling us that the rock contains a diversity of minerals down to the finest scales."
There should be plenty time for Curiosity to solve this mystery as the Mars rover still has two years of its mission left to run.
According to the NASA website
, on Earth, rocks with composition like the Jake rock typically come from processes in the Earth’s mantle beneath the crust, from crystallization of relatively water-rich magma at elevated pressure. Vasavada confirmed that, so far, analysis of Jake revealed a good match for an equivalent type of Earth rock, explaining, “We see a composition that is a good match to a rare but widespread rock type on Earth, one that forms deep inside the Earth as magma moves around and partially crystallizes, leaving basalts that are rich in alkali elements like potassium."
Vasavada emphasised that NASA can't be certain Jake formed in the same way as rocks on Earth. "Like many aspects of planetary exploration," he noted, "we use the long history of Earth studies to form our best ideas to explain Mars."
"Jake is kind of an odd Martian rock," said APXS Principal Investigator Ralf Gellert of the University of Guelph in Ontario, Canada, commenting on the NASA website
. "It's high in elements consistent with the mineral feldspar, and low in magnesium and iron."
The other analysis instrument, ChemCam, had previously found unique compositions at each of 14 target points on the Jake rock, hitting different mineral grains within it.
Curiosity is scheduled to spend about three weeks at a location named Rocknest, a patch of Martian soil where it recently scooped up its first sample. After that, Curiosity is likely to be moved about 100 metres eastwards to carry out rock drilling in search of data to ascertain whether microbial life previously existed on Mars.