Mars Curiosity rover has come across bedrock with surprisingly high levels of silica – something it has never come across before in its nearly three years of operations on the Red Planet.
Silica is a rock-forming compound containing silicon and oxygen – something that is commonly found on Earth as quartz. Curiosity found this bedrock just downhill from a geological contact zone that it has been studying near “Marias Pass” on lower Mount Sharp.
The Curiosity team analysed data sent from the laser-firing Chemistry & Camera (ChemCam) and Dynamic Albedo of Neutrons (DAN) onboard the rover and found silicon and hydrogen in elevated amounts. This led the team to back up the rover 46 meters from the geological contact zone to investigate this high-silica target dubbed “Elk.”
The reason the team is curious about this bedrock is that the high levels of silica could indicate ideal conditions for preserving ancient organic material, if present.
“One never knows what to expect on Mars, but the Elk target was interesting enough to go back and investigate,” said Roger Wiens, the principal investigator of the ChemCam instrument from the Los Alamos National Laboratory in New Mexico. ChemCam is coming up on its 1,000th target, having already fired its laser more than 260,000 times since Curiosity landed on Mars Aug. 6, 2012, Universal Time (evening of Aug. 5, Pacific Time).
Before Curiosity began further investigating the high-silica area, it was busy scrutinizing the geological contact zone near Marias Pass, where a pale mudstone meets darker sandstone.
The rover had reached this area after a steep climb up a 20-foot (6-meter) hill. Near the top of the climb, the ChemCam instrument fired its laser at the target Elk, and took a spectral reading of its composition.
“ChemCam acts like eyes and ears of the rover for nearby objects,” said Wiens.
The rover had moved on before the Elk data were analyzed, so a U-turn was required to obtain more data. Upon its return, the rover was able to study a similar target, “Lamoose,” up close with the MAHLI camera and the arm-mounted Alpha Particle X-ray Spectrometer (APXS).
Curiosity has been working on Mars since early August 2012. It reached the base of Mount Sharp last year after fruitfully investigating outcrops closer to its landing site and then trekking to the mountain. The main mission objective now is to examine successively higher layers of Mount Sharp.