Curiosity scientists find evidence of lake water higher on Mount Sharp than expected

Panorama as of January 17, 2023
Curiosity’s view of the marker band on January 17, 2023, the red dotted line the planned future route. Click for full image.

The science team for the Mars rover Curiosity today revealed that the marker band layer where the rover present sits shows some of the best evidence of liquid water and waves yet seen on Mount Sharp, and it has been found much higher on the mountain than expected.

Having climbed nearly a half-mile above the mountain’s base, Curiosity has found these rippled rock textures preserved in what’s nicknamed the “Marker Band” – a thin layer of dark rock that stands out from the rest of Mount Sharp. This rock layer is so hard that Curiosity hasn’t been able to drill a sample from it despite several attempts. It’s not the first time Mars has been unwilling to share a sample: Lower down the mountain, on “Vera Rubin Ridge,” Curiosity had to try three times before finding a spot soft enough to drill.

Scientists will be looking for softer rock in the week ahead.

As Curiosity climbs the mountain it transitions onto new younger layers of rock. Based on Curiosity’s earlier data lower down the mountain, scientists had assumed it had gone from layers that had been under a past lake to layers that were at the lake’s shoreline to layers where only running water once flowed. They had thought the marker layer and other higher layers would only show evidence of running water. Instead, in the marker layer they have once again found evidence of an ancient lake.

This quote by Ashwin Vasavada, Curiosity’s project scientist, sums things up nicely: “Mars’ ancient climate had a wonderful complexity to it, much like Earth’s.”

Curiosity’s drill fails for the fourth time to drill into the marker band layer on Mt Sharp

The fourth attempt yesterday to use Curiosity’s drill to drill into the marker band layer on Mount Sharp once again was unable to drill down deep enough to obtain a sample.

Despite giving it the “old college try,” Curiosity’s attempt to drill into the Marker Band at the “Encanto” site did not reach sampling depth. Because other rocks around the rover look similar to “Encanto” and are likely also too hard to drill, the Science Team decided to convert the plan to a “Touch and Go.”

Although the Science Team is disappointed to leave this Marker Band location without a sample, Curiosity will use MAHLI, APXS, and ChemCam LIBS to analyze the chemistry and texture of the shallow “Encanto” drill hole and tailings, targeting the intriguing light-toned material exposed in the wall of the drill hole. We may see another location in the Marker Band worth sampling in the near future, but even if we don’t, there will certainly be many more exciting drilling opportunities to look forward to as Curiosity continues her climb up Mt. Sharp!

This drilling difficulty is not a surprise. The marker band is a very distinct flat layer that is seen at about the same elevation on all sides of Mount Sharp. It flatness suggests it is resistant to erosion, which also suggests its material will be hard. The inability of Curiosity’s drill to penetrate it only confirms this.

It also makes getting a drill sample to test even more intriguing. I suspect that the science team is going to try a few more times as it travels forward across the band, as indicated by the red dotted line in the panorama below.
Panorama as of January 17, 2023
Click for full image.

Curiosity climbs onto the Marker Band

Panorama as of January 17, 2023
Click for full image.

Overview map
Click for interactive map.

Curiosity’s exploration of the foothills of Mount Sharp continues. The panorama above, cropped, reduced, and annotated to post here, was taken on January 17, 2023 by the rover’s right navigation camera. It looks forward across the flat marker band terrain that the rover has been studying for the past few weeks.

From orbit, this marker band appears very smooth and flat, and is found in many places on the flanks of Mount Sharp, always at about the same elevation. The arrows in the overview map to the right mark several places near Curiosity where the band is evident. The blue dot marks Curiosity’s present location, the red dotted line its planned route, and the yellow lines indicate the approximate area covered by the panorama above. The distance across the marker band to the uphill slope is about 500 feet.

Now that Curiosity is on the marker band, it no longer looks smooth. Instead, it is a flat plain of many uneven paving stones interspersed with dust. While not as rough as the Greenheugh Pediment, which Curiosity had to retreat from because it was too hard on the rover’s wheels, the marker band is hardly the smooth soft terrain implied by the orbital images.

These paving stones have also proven difficult to drill into, with Curiosity’s drill already failing twice previously because the rock was too hard. That hardness should not be a surprise, however, as this layer’s flatness in many places shows its resistance to erosion.

As it crosses this wide section of the marker band the science team will obviously be looking for more candidate drill sites. Sooner or later one should work.