Martian 'Jake' Resembles Unusual Rocks From Earth's Volcanic Areas

The football size rock named "Jake Matijevic" is the first Martian rock NASA's Curiosity has reached out to and it appears that this rock resembles some unusual rock from volcanic regions of Earth. The rock's compositions tell stories about unseen environments and planetary processes.

In order to study the chemical composition of this rock, the rover team used two different instruments on Curiosity. The results support some surprising recent measurements and provide an example of why identifying rocks' composition is such a major emphasis of the mission.

"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," said Edward Stolper of the California Institute of Technology in Pasadena, who is a Curiosity co-investigator. "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."

On comparing to the composition of the Jake rock to that of the rock on the Earth with the similar composition, it appears that such rocks process in the planet's mantle beneath the crust, from crystallization of relatively water-rich magma at elevated pressure.

Jake was the first rock analyzed by the rover's arm-mounted Alpha Particle X-Ray Spectrometer (APXS) instrument and about the thirtieth rock examined by the Chemistry and Camera (ChemCam) instrument.

On Sept. 22 the two spots that Jake carry was analyzed by the rover's improved and faster version of earlier APXS devices on all previous Mars rovers, which have examined hundreds of rocks.

"Jake is kind of an odd Martian rock," said APXS Principal Investigator Ralf Gellert of the University of Guelph in Ontario, Canada. "It's high in elements consistent with the mineral feldspar, and low in magnesium and iron."

At each of the 14 target point Chemcam spotted unique composition. "ChemCam had been seeing compositions suggestive of feldspar since August, and we're getting closer to confirming that now with APXS data, although there are additional tests to be done," said ChemCam Principal Investigator Roger Wiens (WEENS) of Los Alamos National Laboratory in New Mexico.

In order to examine Jake , the team included the first comparison on Mars between APXS results  along with the results from checking the same rock with ChemCam, which shoots laser pulses from the top of the rover's mast.

"Yestersol, we used Curiosity's first perfectly scooped sample for cleaning the interior surfaces of our 150-micron sample-processing chambers. It's our version of a Martian carwash," said Chris Roumeliotis (room-eel-ee-OH-tiss), lead turret rover planner at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"That first sample was perfect, just the right particle-size distribution," said JPL's Luther Beegle, Curiosity sampling-system scientist. "We had a lot of steps to be sure it was safe to go through with the scooping and cleaning."

Curiosity is spending about three weeks at Rocknest; next, the team plans to drive it about 100 yards eastward and pick a rock as the first target for the rover's drill.