NASA's Curiosity rover has discovered two-toned mineral ridges after climbing a mountain in Mars, catching a glimpse of what fluid movement would have been like in the past. This fluid movement is believed to have occurred after wet environmental conditions formed deposits in a lake bed the rover examined previously at the base of the mountain.
Rock samples were analyzed from three different parts on the lower portions of the mountain and results reveal that each contains different mineral compositions. The differences in mineral content, alongside the discovery of prominent veins uphill, show that Mount Sharp's layers provide records of the different stages the environment in the area went through.
Found in a site named "Garden City," the two-tone mineral veins look like a ridge network left behind after bedrock eroded away. The ridges can measure up to 2.5 inches in height and half of that in width, and all feature light and dark material.
Linda Kah, a member of the Curiosity science team from the University of Tennessee, Knoxville, likened the ridges to ice cream sandwiches--white in the center and dark on the edges.
"These materials tell us about secondary fluids that were transported through the region after the host rock formed," she said.
Mineral veins like the ones found in Garden City form when fluids pass through cracked rocks, depositing minerals in the fractures and subsequently changing the rock's chemistry around the fractures.
Kah said the Curiosity team is eager to learn more about the sequence of events leading to the creation of the mineral veins as well as the chemistry of the fluids that moved through the terrain.
So far, researchers know that mud in the area the rover landed dried, hardening before fractures were formed. Dark material lining fractures point to an earlier fluid flow compared to the white veins, although both represent events occurring after the formation of the cracks.
Garden City is located around 39 feet above the "Pahrump Hills" bottom edge, forming the bedrock outcrop comprising Mount Sharp's basal layer at the center of the Gale Crater. The Curiosity rover spent around six months assessing the first 33 feet of Pahrump Hills' elevation, going from the lower edge to the area's higher portions three times to profile rock chemistry and structures vertically. This allowed the rover's team to pinpoint the best spots for drilling for further examination. Drilled samples came from "Confidence Hills," "Mojave" and "Telegraph Peak."
