As far as rocks on any planet go, this formation looks fascinating. But it's even more fascinating to know that this particular rocky outcrop was photographed on Mars by NASA's Curiosity rover and it holds further clues to the red planet's wet past and, potentially, Mars' habitable potential.
PHOTOS: Curiosity Drills Hole Into Mars Rock
Currently studying the "Pahrump Hills" region at the base of Mount Sharp in the center of Gale Crater, this new view snapped by Curiosity on March 18 shows a work site Curiosity's mission scientists call "Garden City." This area is interesting as it shows two-tone mineral veins protruding from the surrounding rock.
The tough mineral veins were formed in Mars' ancient wet past and they are sticking out of the rock up to 6 centimeters (2.5 inches) high. This means that the veins formed within the rock and the softer surrounding bedrock has since eroded away.
When comparing the geology of this particular area with the rocks that Curiosity has analysed in lower sections of Mount Sharp, a story emerges Mars' ancient geological history.
"Some of (the mineral veins) look like ice-cream sandwiches: dark on both edges and white in the middle," said Linda Kah, Curiosity science-team member at the University of Tennessee, Knoxville, in a NASA Jet Propulsion Laboratory news release. "These materials tell us about secondary fluids that were transported through the region after the host rock formed."
ANALYSIS: Curiosity Finds Tantalizing Mineral Clues for Mars Habitability
Like previous rocks studied by Curiosity, the prominent veins at Garden City were formed when water flowed through cracks in bedrock, depositing minerals inside these fractures. The chemistry of the rock neighboring the fractures became altered and these tough veins formed. Previously, the robotic geologist has found other bright veins rich in calcium sulfate.
However, Garden City appears to be different from previous samples - the darker material in the veins suggest an early episode of water on Mars, whereas the brighter mineral deposits shows a later episode of water flow.
"At least two secondary fluids have left evidence here," added Kah. "We want to understand the chemistry of the different fluids that were here and the sequence of events. How have later fluids affected the host rock?"
Curiosity has been studying rocky configurations since landing on the Martian surface in 2012.
Over the past 6 months, the rover has been focused on Pahrump Hills, studying the layers of rock spanning an elevation of only 10 meters. Garden City is the highest point (so far) of this survey and there are very obvious changes in the mineral history over this small cross section.
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"We investigated Pahrump Hills the way a field geologist would, looking over the whole outcrop first to choose the best samples to collect, and it paid off," said David Blake of NASA's Ames Research Center, Moffett Field, Calif., and principal investigator for Curiosity's Chemistry and Mineralogy (CheMin) instrument.
Geology is as much about the science of rocks as it is about looking back in time. Looking through the different layers of sedimentary rock reveal periods of when a region was covered in water. Likewise, different mineral layers reveal episodic water flow through cracks in rock, locking a chemical "tag" within those cracks. Curiosity is equipped with a complex suite of tools that analyse these layers, slowly building a picture of the geological history of Gale Crater.
This latest picture from Mars certainly looks like Curiosity has hit the geological jackpot; not only is there obvious signs of minerals that were formed in the presence of water in sedimentary rock (which was also formed through the presence of water), but the two-toned minerals are indicative of two distinctive wet periods. But what does it mean? For now, we'll need more data, but that's why Curiosity is hard at work, exploring the layers of Mount Sharp, slowly adding more detail to the rich history of water and organics on the red planet.
For more detail behind this most recant Mars finding and its chemical implications, read the JPL news release.