Tag: geology

The journey so far of China’s Zhurong Mars rover

11:07 am

Zhurong's journey on Mars, as seen by MRO
Click for full image.

Elevation map and wider overview
Click for full image.

Cool image time! The science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) today released a new orbital photo that shows the entire journey on Mars of China’s Zhurong rover, since it landed in May 2021. That image, reduced to post here, is to the right. From the caption, written by Alfred McEwen of the Lunar & Planetary Laboratory in Arizona:

This HiRISE image, acquired on 11 March 2022, shows how far the rover has traveled in the 10 months since it landed.

In fact, its exact path can be traced from the wheel tracks left on the surface. It has traveled south for roughly 1.5 kilometers (about 1 mile). This cutout highlights the rover and the rover’s path (with contrast enhanced to better reveal the tracks).

The white curves that the rover has apparently been inspecting as it moved south are called megaripples, mid-size sand dunes from three to six feet in height that are generally found to be inactive, though not always. From a recent report about Zhurong’s findings:

“The examples Zhurong has visited appear very bright-toned in satellite images taken from orbit, and the team thinks that this is because the megaripples are covered with a layer of very fine dust,” says Matt Balme at the Open University, UK, who wasn’t involved in the analysis. “This means these features are probably currently inactive, as any present-day windblown sand would tend to remove the dust.”

That report used data from the rover’s first sixty days on Mars, after it had passed its first megaripple and had just reached the parachute and backshell. It does not include any later data in the past eight months, as Zhurong rolled past another nine megaripples and several small craters.

It also doesn’t include any data obtained as the rover skirted the wide apron that surrounds the large depression in the lower left. That depression looks like a crater at first glance, but because it appears to be on top of a mound it could instead by an old pitted cone. There are a lot of these cones in this region of the northern lowland plains of Mars, and planetary scientists really want to know whether they were formed from erupting ice, lava, or mud.

The Chinese have so far not released any data on what they have found in these later travels. We shall have to wait for further published papers.

The wider elevation overview map to the right, first published on August 24, 2021 and cropped and annotated to post here, shows Zhurong’s future potential geological targets to the south. The cone to the southwest as well as the nearest scarp to the south are probably the rover’s primary goals.

Though the released results have hinted that the geology here was shaped by both wind and water, direct evidence for water has not been found, or revealed by the Chinese. Zhurong has a radar sensor that could detect evidence of near surface underground ice, if it was there. As far as I know at this point, no results from that instrument have as yet been published.

2 comments

Recent avalanche on Mars

12:06 pm

Close-up comparison of slump
Click for full image.

Wide view comparison of slump
For full images go here and here.

Cool image time! Today the science team for the high resolution camera on Mars Reconnaissance Orbiter (MRO) released images showing a very recent avalanche, or slumping, on the interior slopes of what looks like a small three-mile-wide crater inside the easternmost reaches of the giant canyon Valles Marineris.

The comparison above, reduced and rotated to post here, is their close-up showing the change, which occurred sometime between March 2021 and February 2022. The wider comparison on the right, cropped, reduced, and annotated by me, shows a wider view to help place this slumping in the context of the crater.

Calling this an avalanche is not really accurate, as it isn’t really the fall of boulders and rocks, but the quick slumping downward of an entire section of what looks like dust or sand. As Alfred McEwen of the Lunar & Planetary Laboratory in Arizona writes in the caption:
» Read more

1 comment

NASA extends Ingenuity’s mission through September ’22

9:31 am

Overview map
Click for interactive map.

NASA yesterday officially extended Ingenuity’s flight operations on Mars at least through September 2022, outlining in detail the helicopter’s hoped-for flight targets.

The map to the right shows the helicopter’s present location with the green dot, with its two possible future routes proceeding from this location indicated by dashed lines. The red dot indicates Perseverance’s present location, with its planned route from this spot indicated by the dashed lines.

Scheduled for no earlier than March 19, Ingenuity’s next flight will be a complex journey, about 1,150 feet (350 meters) in length, that includes a sharp bend in its course to avoid a large hill. After that, the team will determine whether two or three more flights will be required to complete the crossing of northwest Séítah.

Once Ingenuity crosses the rough terrain and reaches the delta, it will then be used to do more route scouting for the rover.

Upon reaching the delta, Ingenuity’s first orders will be to help determine which of two dry river channels Perseverance should take when it’s time to climb to the top of the delta. Along with routing assistance, data provided by the helicopter will help the Perseverance team assess potential science targets. Ingenuity may even be called upon to image geologic features too far afield (or outside of the rover’s traversable zone), or perhaps scout landing zones and caching sites for the Mars Sample Return program.

This ambitious plan exists because both the helicopter and its engineering team have far exceeded expectations. At the moment, there is no obvious reason why Ingenuity cannot continue to operate for years, an expectation that no one predicted.

0 comments

Mesa in the Martian northern lowlands

3:21 pm

Mesa in the dry northern lowlands
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on February 2, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and shows a mesa sticking up on the relatively flat and featureless northern lowland plains in Utopia Planitia, the second largest impact basin on Mars.

The full image shows three such mesas. Though pictures taken in the northern lowlands of Utopia tend to show evidence of buried ice or glaciers, the impression I get from this picture is one of dryness. If there is any ice here, it is below ground. And even that seems unlikely. The surface surrounding nearby craters does not have that squishy and slushy look that is seen in the north when an impact occurred on near surface ice. Instead, the ground looks solid.

The overview map below reinforces this impression.
» Read more

0 comments

Ingenuity completes 21st flight on Mars

3:54 pm

Overview map
Click for interactive map.

According to a tweet today from JPL, the Mars helicopter Ingenuity has successfully completed its 21st flight on Mars, traveling 1,214 feet in two minutes and nine seconds at an average speed of 12.6 feet per second.

The red dot on the map to the right shows Perseverance’s location as of today. The green dot indicates Ingenuity’s position before the 21st flight. Since neither the Perseverance nor the helicopter teams have posted any updates describing the 21st flight, it is difficult to indicate a precise location for its landing site. All we know is that the helicopter is supposed to fly to the northwest, cutting across the rougher region while the rover follows the tan dotted line around that rough region, with both targeting the delta to the northwest.

As a guess, I have placed a black dot about 1,200 feet to the northwest.

0 comments

More thumbprints on Mars!

1:22 pm

Thumbprints on Mars
Click for full image.

Cool image time! Among the many strange and unexplained geological features that scientists have identified on Mars, the thumbprint feature is one of the most intriguing. The photo to the right, cropped and reduced to post here, is a fine example, and was taken on September 10, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The thumbprints are the lighter splotches, and are generally found near curved ridges located mostly in Martian lowlands. All appear to have crater-like features in them, though these craters are not impact craters, but likely (though not confirmed) caused by some form of underground eruption, be it mud, ice, lava or something else. Though scientists do not yet really understand the process that formed the thumbprints, the data strongly suggests that they formed in connection with glacial events. From this 2003 paper [pdf]:

TT [thumbprint terrain] as well as the associated trough systems were formed by a glacial mechanism. [Elevation] data show that the trough systems consistently lie topographically above the TT; this implies that if they were they formed by the same glacier, the troughs must have formed before the glacier retreated and formed the TT.

The splash apron around the crater near the bottom of the photo supports the glacial theory, implying the presence here of underground ice.

Scientists have also theorized wind processes and cinder cones as explanations for these features.

These particular thumbprints are located, as shown in the overview map below, in the same general area as a previous cool image of thumbprints, from April 2019.
» Read more

1 comment

Monitoring one glacier flowing off a mesa in Mars’ glacier country

1:28 pm

Vicous glacial flow on Mars
Click for full image.

Today’s cool image takes us back to the mesa in Mars’ glacier country that first clued me in on the prevalence of ice in the Martian mid-latitudes. The photo to the right, rotated, cropped, and reduced to post here, was taken on November 13, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a viscous flow coming down from a hollow on that mesa’s southern wall.

The new image has likely been taken to see if anything has changed since the previous image was taken in 2014. Based on the resolution published at the MRO website, nothing seems to have changed, though with more sophisticated software higher resolution versions of the images are available that might show some changes.

In my first post about Mars’ glacier country in December 2019, this flow was one of four that I featured coming off this same 30-mile wide mesa, as shown by the first overview map below.
» Read more

0 comments

Fractured terrain on Mars

1:39 pm

Fractures on Mars
Click for full image.

Today’s cool image, which at first glance does not seem so puzzling, actually falls into my “What the heck?” category of baffling Martian geology. The picture to the right, cropped and reduced to post here, was taken on January 15, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Labeled “Avernus Cavi fractures”, it shows what resembles the well-documented chaos terrain seen in many places on Mars, where erosion over eons along fault lines creates mesas with random criss-crossing canyons.

The problem is that this location is practically on the Martian equator, and chaos terrain tends to be found in the mid-latitude bands where there are many glaciers, suggesting the cyclical waxing and waning of those glaciers is what causes the erosion. Here at the Martian equator the terrain is very dry. No glaciers.

Moreover, note the higher mesa near the top center. Its flat top suggests that once this terrain was covered with an even higher layer of material, almost all of which was stripped away evenly everywhere, except where that mesa sits. As an amateur geologist I can’t think of any sequence of events that would do such a thing. I suspect professionals might have problems themselves.

Then there are the small parallel ridges. They suggest dunes, especially inside the depressions where sand and dust can get trapped. On the mesa tops however these ridges are more mysterious. Why for example are they aligned with the small ridge in some hollows, but not others? They in many ways remind me of the ridges in this earlier “What the heck?” cool image, also right on the equator.

The overview map below provides some help, though not much.
» Read more

2 comments

The layered Martian history exposed in Valles Marineris

12:28 pm

Overview map

The layers in Valles Marineris
Click for full image.

Cool image time! Like the Grand Canyon in the United States, Mars’ largest canyon, Valles Marineris, appears to have been carved out of a layered terrain, thus exposing those many layers in the walls of the canyon.

Valles Marineris, however, is much much larger than the Grand Canyon. You could fit dozens of Grand Canyons inside it and hardly fill it. Yet, its walls have the same layered look, suggesting that in Mars’ long geological history, first came many events that laid down new layers time after time, followed by a long period when the laying ceased and other events carved out the canyon to its almost 30,000 foot depth (which by the way is also about six times deeper than the Grand Canyon).

Today’s cool image to the right, cropped and reduced to post here, was taken on September 5, 2021 and shows a terraced terrain on the floor of Candor Chasma, one small side canyon of Valles Marineris that is still much larger than the Grand Canyon. The black dot in the overview map above indicates its location. I roughly estimate the elevation difference between the high and low spots in the picture is about 3,000 feet, a difference that while two-thirds that of the depth of the Grand Canyon is almost unnoticeable within the depths of Valles Marineris.

This layering is probably the canyon’s most important geological feature. See these previous cool images here and here for other examples. When geologists finally arrive on Mars and can begin dating these layers in detail they will likely reveal the planet’s entire geological history, going back five to six billion years.

Most of the layers are probably volcanic flood lava laid down by repeated eruptions from the giant volcanoes to the west. In between and within however will be deposits from the Martian atmosphere, telling us its composition and thickness. All told, the layers of Valles Marineris will likely unlock almost all of the most basic secrets of Martian geology.

We merely have to go there to find out.

0 comments

Martian crater overwhelmed by glacier?

1:32 pm

Martian crater overwhelmed by glacier?
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on January 28, 2022 by the high resolution camera on Mars Reconnaissance Orbiter. It shows what the science team labels a “modified crater.”

What I see is an old crater almost completely covered by glacial material. That material however is also very old, as there are numerous small craters on its surface, enough that it must have been here for a long time. Its cracked surface also suggests this glacier is very old.

Thus, while we might have ice here, buried by a thin layer of dust and debris to prevent it from sublimating away, it must be very old ice. The many climate cycles caused by the extreme swings in Mars’ rotational tilt, from 11 to 60 degrees, have apparently not caused this ice to ebb and flow very much.

Might it therefore not be ice, but hardened lava?

The location, as shown by the overview map below, provides some context, but only makes this mystery more puzzling.
» Read more

2 comments

Scientists: Yutu-2 spots tiny glass globules similar to those found by Apollo astronauts

9:45 am

According to a paper just published Chinese scientists running the Yutu-2 rover on the far side of the Moon have spotted several tiny glass globules similar to those found by Apollo astronauts.

Xiao and his team believe the small spheres, which are between 0.59 and 0.79 inches (1.5 to 2.5 centimeters) across, were probably formed by relatively recent meteor impacts. Specifically, the researchers believe that the globules formed from anorthosite, a volcanically-formed rock rich in the mineral feldspar, after a high-energy impact melted the rock and reformed into spheres.

In appearance these Yutu-2 globules appear translucent, unlike the Apollo globules which were either dark or opaque. Since the rover did not do spectroscopy on these objects before moving on, however, their actual make-up is unknown, with the speculations by the researchers above merely that, speculations, though reasonable.

0 comments

Scientists: Martian topography in one region suggests the past existence of lakes and river networks, but not a large single ocean

3:53 pm

Based on a just published paper, scientists using orbital topography data and imagery have concluded that more than three billion years ago on Mars ancient rivers in the transition zone between the southern cratered highlands and the northern lowland plains fed into numerous lakes in the lowlands, not a single large ocean as some scientists posit.

From their abstract:

The northern third of Mars contains an extensive topographic basin, but there is conflicting evidence to whether it was once occupied by an ocean-sized body of water billions of years ago. At the margins of this basin are the remnants of deltas, which formed into water, but the size and nature of this water body (or water bodies) is unclear, and detailed investigations of different regions of the basin margins are necessary.

In this study, we use high-resolution image and topographic datasets from satellites orbiting Mars to investigate a series of water-formed landforms in the Memnonia Sulci region, set along the boundary of Mars’s northern basin. These landforms likely formed billions of years ago, providing evidence for ancient rivers and lakes in this region. The geologic evolution of these rivers and lakes was complicated, likely influenced by water-level fluctuations, changes in sediment availability, and impact cratering. Our topographic analysis of these rivers and lakes suggests that they terminated in a series of ancient lake basins at the boundary of Mars’s northern basin, rather than supplying a larger, ocean-sized body of water. [emphasis mine]

Overview map

The Memnonia Sulci region is in the cratered highlands just south of the Medusae Fossae Formation, the largest volcanic ash deposit on Mars. The region of study in it is marked by the blue dot in the overview map to the right.

The study does not preclude the possible existence of a northern ocean on Mars, but it says that at least in this region at the equator, it did not exist. Instead, the various river valleys drained into separate smaller and relatively short-lived lakes.

7 comments
1 … 78 79 80 81 82 … 157