Tag: geology

Scientists refine Martian interior based on quakes detected by InSight

9:11 am

Martian quake map as seen by InSight

Scientists today published three studies in the journal Science outlining their conclusions about the interior of Mars, based on the quakes that have been detected by InSight since it arrived on Mars in November 2018.

Reporting in a trio of studies published in the July 23rd Science, the Insight science team has now analyzed about 10 marsquakes to make the first direct observations of the structure within another rocky planet. The results — a surprisingly thin crust, an undifferentiated mantle, and a larger-than-expected core — will help determine how Mars formed and evolved.

There results are essentially what was described in April by the InSight science team at the annual 52nd Lunar and Planetary Science Conference (and reported here but no where else), though now more carefully and thoroughly described.

The discovery that the Martian crust is much thinner than expected, either 12 or 24 miles thick, with a core that is still liquid, has ramifications that might help explain both the planet’s formation and its volcanic history and giant volcanoes.

One piece of good engineering news in connection with the lander InSight:

Despite a dust-fueled energy crisis earlier this year, the solar-powered lander has since regained some power-generating capacity. “We are at least safe for this season’s winter and probably far into 2022,” Stähler says.

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The wind-swept volcanic ash plains of Mars

2:19 pm

Overview map

Cool image time! In Mars’ volcano country lies the planet’s largest ash deposit, dubbed the Medusae Fossae Formation. Scientists believe that this gigantic deposit, with a size comparable to the nation of India, was laid down by muliple volcanic eruptions over several billion years and is the source of most of the dust seen on the Red Planet.

The overview map on the right shows the location of this ash deposit on Mars. The white cross indicates the location of today’s cool image, found below.
» Read more

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It’s drill time for Perseverance!

8:18 am

The Perservance science team is preparing the rover for its first drill hole and the first collection of a sample to cache so that a future spacecraft can return it to Earth.

They are presently at the general location where they wish to drill, and are looking for the exact right spot.

The sampling sequence begins with the rover placing everything necessary for sampling within reach of its 7-foot (2-meter) long robotic arm. It will then perform an imagery survey, so NASA’s science team can determine the exact location for taking the first sample, and a separate target site in the same area for “proximity science.”

“The idea is to get valuable data on the rock we are about to sample by finding its geologic twin and performing detailed in-situ analysis,” said science campaign co-lead Vivian Sun, from NASA’s Jet Propulsion Laboratory in Southern California. “On the geologic double, first we use an abrading bit to scrape off the top layers of rock and dust to expose fresh, unweathered surfaces, blow it clean with our Gas Dust Removal Tool, and then get up close and personal with our turret-mounted proximity science instruments SHERLOC, PIXL, and WATSON.”

“After our pre-coring science is complete, we will limit rover tasks for a sol, or a Martian day,” said Sun. “This will allow the rover to fully charge its battery for the events of the following day.”

Sampling day kicks off with the sample-handling arm within the Adaptive Caching Assembly retrieving a sample tube, heating it, and then inserting it into a coring bit. A device called the bit carousel transports the tube and bit to a rotary-percussive drill on Perseverance’s robotic arm, which will then drill the untouched geologic “twin” of the rock studied the previous sol, filling the tube with a core sample roughly the size of a piece of chalk.

Perseverance’s arm will then move the bit-and-tube combination back into bit carousel, which will transfer it back into the Adaptive Caching Assembly, where the sample will be measured for volume, photographed, hermetically sealed, and stored. The next time the sample tube contents are seen, they will be in a clean room facility on Earth, for analysis using scientific instruments much too large to send to Mars.

Not all drill samples will be cached in this manner.

With this press release and press conference NASA continued to push the fiction to the press that Perservance’s prime mission is to search for life. That is a lie designed to catch the interest of ignorant journalists who don’t know anything. The rover’s real mission is to study the overall Martian geology in Jezero Crater in order to better under the planet’s present geology as well as the geological history that made it look like it does today.

If the scientists using Perseverance find evidence of life, wonderful, but that is not their prime goal.

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Another “What the heck?” photo from Mars

1:59 pm

Isolated clump of mounds on Mars
Click for full image.

The cool image to the right, cropped and reduced to post here, was taken a decade ago, on August 25, 2011, by the context camera on Mars Reconnaissance Orbiter (MRO), It shows a flat plain with a sudden clump of mounds or hills at the center.

This is one of those pictures from Mars which I like to call a “What the heck?” image. What caused the mounds, and why are they found only in this concentrated clump, with the rest of the terrain around them generally flat?

Though the context image was taken a decade ago, no follow-up high resolution images were taken of this area until very recently.

Below is the one recent high resolution image taken by MRO on May 12, 2021, cropped and reduced to show the bottom half of the mound clump as shown by the white box. It makes the mystery even more puzzling.
» Read more

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Ice-filled craters in Mars’ glacier country?

1:10 pm

Craters in Protonilus Mensae
Click for full image.

Today’s cool image returns us to the chaos region dubbed Protonilus Mensae, the middle of three adjacent mensae regions in the northern hemisphere that I like to dub Mars’ glacier country because there is so much evidence of buried ice there.

The photo to the right, cropped to post here, was taken on May 31, 2021 by the high resolution camera of Mars Reconnaissance Orbiter (MRO). Titled “Layered Feature in Crater in Protonilus Mensae,” the section I have posted focuses on several craters, with the one with the central mesa likely the picture’s target. Based on many similar features found in craters in this region, it is somewhat safe to assume that this mesa is made of buried ice.

The overview map below as always provides the context.
» Read more

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Cracks, chaos, and maybe caves in one place on Mars

11:34 am

Mosaic of Avernus Cavi fissures
Click for higher resolution. Original images found here and here.

Today’s cool image to the right is a mosaic I have made from two images taken by the context camera on Mars Reconnaissance Orbiter (MRO), showing a most intriguing region on Mars dubbed Avernus Cavi, located in the large volcanic plain called Elysium Planitia between the giant volcanoes Elysium Mons and Olympus Mons, a region I like to call Mars’ volcano country.

The mosaic shows in one picture much of the typical terrain in Avernus Cavi. We see many linear depressions or cracks, created when the ground stretched and cracked at weak points. We also see many depressions that suggest sinkholes, places where the surface sagged down because of a void below ground.

The area of knobs and mesas in the picture’s southeast quadrant is very typical Martian chaos terrain, the later result of long term erosion of these cracks and depressions.

The white box shows the area covered by the image below.
» Read more

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The lacy rocks of Mars

9:36 am

Lacy rocks on Mars
Click for full image.

Cool image time! The image to the right, cropped and reduced to post here, was taken on July 16, 2021 by the Mars rover Curiosity, using its high resolution mast camera.

There isn’t much to say. These are alien rocks, created in a place with a gravity only about a third that of Earth’s in a climate that is very different. Their delicate nature suggests we are looking at something that was once more substantial and has since been undergoing erosion.

Nor has it been that unusual to find rocks so dainty on Mars. In fact, the more Curiosity has climbed, the more such things have been visible. And similar things were seen by the rovers Spirit and Opportunity.

How such rocks formed initially in the far past, under what climate conditions, remains the number one mystery on Mars. What is now causing it to flake away into such a finespun gossamer of complexity is as much a mystery, tied more to the climate and geology of Mars today.

This rock sits on the bottom flank of Mt Sharp in Gale Crater, at the highest elevation Curiosity has yet climbed. At this point the rover has just entered a new geological unit, what scientists have dubbed the sulfate unit. The evidence gathered from a distance (that so far appears confirmed by recent observations) suggest that this unit was formed under a fluctuating environment that laid down many layers of sediment as conditions ebbed and flowed.

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First attempts to map the layered geology of Mars

1:47 pm

layers in Jiji Crater on Mars
Click for full image.

Today’s cool image illustrates well the central task of much of today’s geological research on Mars, using the orbital images to try to map out the visible geological layers seen, and figure out if those layers mark over wide regions specific geological epochs, as they do on Earth.

The photo to the right, cropped and reduced to post here, was taken on May 4, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and featured on July 12th as a captioned image entitled “Layers Blanket a Crater Floor.” From the caption:

This image shows a layered rock formation within Jiji Crater that has eroded into buttes and stair-like layers.

This formation extends west and east. Similar layered rocks are within several craters in Arabia Terra and Meridiani Planum, including [nearby] Sera and Banes craters. The similarities suggest that the same process was forming deposits over a large geographic area long ago. Our image also indicates that much of the formation has eroded away relative to what has remained.

As you can see in the photo, the layers form a neat staircase of terraces descending from the south crater rim to the crater floor. They suggest that once the crater was filled with this material, which over time eroded away.

An image of similar layered buttes and mesas in Sera crater, only about 20 miles away, was featured here on Behind the Black in December 2020 The overview map below shows the relationship between Jiji, Sera, and Banes craters.
» Read more

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Craters on Ganymede’s striped surface

11:27 am

Craters on Ganymede
Click for full image.

Cool image time! The photo to the right, cropped to post here, is a color enhanced section taken from of one of the images taken by Juno when it did a close fly-by of the Jupiter moon Ganymede back on June 7, 2021.

The enhancement was done by citizen scientist Navaneeth Krishnan, using a wider Juno image of Ganymeded enhanced by citizen scientist Kevin Gill. That wider image is below, and marks the area covered by this first image with a white box.

In this one picture we can see many of the geological mysteries that have puzzled scientists since the Galileo orbiter first took close-up images back in the 1990s. We can see patches of grooved terrain with the grooves in the different patches often oriented differently. We can also see bright and dark patches that while they overlay the grooved terrain they bear no correspondence to those grooved patches. And on top of it all are these small craters, impacts that obviously occurred after the formation of the grooves.
» Read more

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Clashing layers in Mars’ largest canyon

1:20 pm

Clashing layers on a mountain slope on Mars
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on May 27, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows the clash of different layers on the western slope of a mountain within Mars’ largest canyon, Valles Marineris.

The scientist have labeled this a “possible angular unconformity.” In geology an unconformity generally refers to a gap in a series of layers, a period when instead of the layers being deposited they are being eroded away, leaving no record for that time period. An angular unconformity adds tilting to the older layers, which after erosion are then covered by new layers that are oriented somewhat differently.

Based on these definitions, what the scientists suspect is that the brighter layers to the left and lower down the mountain are older. After a period of erosion new layers were deposited on top at a different angle, forming the stripe of layers going from center left up to center right.

The swirly nature of the material on the top of the ridge suggests to me that these layers might be volcanic in nature, but that’s a pure uneducated guess. What some scientists do believe (but have not yet conclusively proven) is that the lower older layers are sediments laid down by an ancient lake that once filled the canyon here.

The overview map below provides a wider view and some context.
» Read more

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Ingenuity’s view of Jezero Crater during its 9th flight

11:57 am

Ingenuity looks across Jezero Crater
Click for full image.

Overview map
Click for interactive map.

Cool image time! The photo above, cropped, enhanced, and reduced to post here, was taken on July 5, 2021, about thirty seconds after Ingenuity had taken off on its 9th flight on Mars. I have increased the contrast slightly to bring out the features. This is a raw image, so I do not think the colors are accurate, and I also do not know why the middle of the image is brighter than the edges.

The red lines on the map to the right indicates the general area this image captures. Essentially, once the helicopter reached its flying altitude after liftoff the engineers had it tilt so that it could see the route it was about to take to the southwest. As they noted in their description of this flight,

We began by dipping into what looks like a heavily eroded crater, then continued to descend over sloped and undulating terrain before climbing again to emerge on a flat plain to the southwest.

I think that crater is visible on the left edge of this picture.

So far 180 raw images from Ingenuity have arrived at JPL. There might be a few more, but I think this is the bulk from the flight. Of these, all but nine are black and white and point straight down. The nine color images seem tilted up towards the horizon to various degrees, though the image above is the only one that captures the horizon itself and the distance mountains of Jezero Crater’s rim.

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