This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows a site with a network of prominent mineral veins below a cap rock ridge on lower Mount Sharp. Credit: NASA/JPL-Caltech/MSSS

This view from the Mast Camera (Mastcam) on NASA’s Curiosity Mars rover shows a site with a network of prominent mineral veins below a cap rock ridge on lower Mount Sharp.
Credit: NASA/JPL-Caltech/MSSS

NASA’s Curiosity Mars rover has surveyed prominent mineral veins at the site dubbed “Garden City” – features that vary in thickness and brightness.

For example, types of vein material evident in that area include: 1) thin, dark-toned fracture filling material; 2) thick, dark-toned vein material in large fractures; 3) light-toned vein material, which was deposited last.

Mineralized fractures

Mineral veins such as these observed by Curiosity form where fluids move through fractured rocks, depositing minerals in the fractures and affecting chemistry of the surrounding rock. In this case, the veins have been more resistant to erosion than the surrounding host rock, according to a Jet Propulsion Laboratory news release.

Researchers used the Mastcam and other instruments on Curiosity to study the structure and composition of mineral veins at Garden City, for information about fluids that deposited minerals in fractured rock there.   Credit: NASA/JPL-Caltech/MSSS

Researchers used the Mastcam and other instruments on Curiosity to study the structure and composition of mineral veins at Garden City, for information about fluids that deposited minerals in fractured rock there.
Credit: NASA/JPL-Caltech/MSSS

Researchers used the rover in March 2015 to examine the structure and composition of the crisscrossing veins at Garden City – a site that for geologists, offers a three-dimensional exposure of mineralized fractures in a geological setting called the Pahrump section of the Lower Murray Formation.

Still alive

Meanwhile, the veteran Opportunity rover continues to survey a different site on Mars.

NASA’s Mars Exploration Rover (MER) Project landed twin rovers Spirit and Opportunity on Mars in 2004 to begin missions planned to last three months. Both rovers far exceeded those plans. Spirit worked for six years, and Opportunity is still active.

“Opportunity is currently on the southern side of Marathon Valley, on a north facing slope,” said Ray Arvidson of Washington University in Saint Louis. He is MER Deputy Principal Investigator.

Opportunity's Navigation Camera took this image on Sol 4181. Credit:  NASA/JPL-Caltech

Opportunity’s Navigation Camera took this image on Sol 4181.
Credit: NASA/JPL-Caltech

“For the past one-and-a-half weeks we have been mounting flash and downloading Pancam and Navcam images acquired of the Valley floor,” Arvidson said, “the last time we mounted and stored data in flash.”

This should all be done over the next few sols, Arvidson added, “and then we will go back into RAM mode, perhaps for the remainder of the winter campaign.”

Bright red veins

Winter solstice is on January 3, 2016, Arvidson told Inside Outer Space. “The current location is really interesting, with lots of outcrop on the southern wall, exposing dark rocks shot through with bright red veins and/or layers, likely alteration zones,” he said.

“We will explore these outcrops during the winter to put together, through a lot of detective work, what is carrying the smectite [clay minerals] signature we see from CRISM. I think the red zones are the key, but more to follow in a few months,” Arvidson said.

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is an instrument on the Mars Reconnaissance Orbiter (MRO), launched in 2005, with the primary objective to search for mineralogic evidence for past water on Mars.

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