Tag: geology

Colorful Vesta

6:44 pm

False color of Vesta

Tonight’s press conference at the American Geophysical Union conference focused on the latest results from Dawn, orbiting the giant asteroid Vesta. Or to put it as scientist Vishnu Reddy put it, “Vesta is the most colorful asteroid in the solar system.”

At least, in geological terms. To our human eye the asteroid wouldn’t be so spectacular. However, the false color images released by the scientists show the global geological diversity of Vesta. From the press release:
» Read more

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Mountains and buried ice on Mars

9:03 am

Mountains and buried ice on Mars.

New images from the high-resolution stereo camera on ESA’s Mars Express orbiter allow a closer inspection [of the Phlegra Montes mountain range] and show that almost every mountain is surrounded by ‘lobate debris aprons’ – curved features typically observed around plateaus and mountains at these latitudes. Previous studies have shown that this material appears to have moved down the mountain slopes over time, and looks similar to the debris found covering glaciers here on Earth.

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Chile’s powerful Cerro Hudson volcano is threatening to erupt

1:41 pm

Chile’s powerful Cerro Hudson volcano has come back to life and is threatening a major eruption.

Patagonians are worried. Many remember Mount Hudson’s catastrophic eruptions of 1971 and 1991. The latter eruption was one of the most violent registered eruptions in Chile, and lasted for five months. At its peak it turned day into night, making the banks of nearby Huemules, Cupquelan and Ibáñez Rivers collapse with ash. Many areas in the region are still covered with ash, pumice and other volcanic rocks. “These are the characteristics of this highly explosive volcano,” said Juan Cayupi, a volcanologist at the National Emergency Office.

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Catching an avalanche on Mars, as it happens

4:38 pm

The Mars Reconnaissance Orbiter team today released this really cool image from Mars, showing an avalanche near the North Pole, in progress. The image looks directly down the cliff face from above. At the base of the cliff we can see the dust cloud from the crash of material billowing out away from the scarp.

What impresses me most about this image is that it was taken by an orbiting spacecraft approximately 200 miles above the planet’s surface, moving at thousands of miles an hour. Yet, the camera not only had the resolution to see the cloud of dust, it could snap the image fast enough to capture the actual fall of material (the white wisps down the side of the cliff that are reminiscent of a waterfall).

Also intriguing is the visible steep face of the cliff face itself. I know a lot of rock climbers who would love to literally get their hands (and chocks) on that rock face. And in Mars’s one-third gravity, rock climbing would surely be different.

avalanche on Mars

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The strange rubbing boulders of Chile

8:55 am

The strange rubbing boulders of Chile.

Then, on another trip to the Atacama, Quade was standing on one of these boulders, pondering their histories when a 5.3 magnitude earthquake struck. The whole landscape started moving and the sound of the grinding of rocks was loud and clear.

“It was this tremendous sound, like the chattering of thousands of little hammers,” Quade said. He’d probably have made a lot more observations about the minute-long event, except he was a bit preoccupied by the boulder he was standing on, which he had to ride like a surfboard. “The one I was on rolled like a top and bounced off another boulder. I was afraid I would fall off and get crushed.”

The abstract is here.

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Rough Terrain

10:21 pm

The Dawn scientists have released another spectacular image of the south polar mountain on Vesta whose relative size is three times that of Mount Everest. More information about the image can be found here. From the caption:

The peak of Vesta’s south pole mountain, seen in the center of the image, rises about 13 miles (22 kilometers) above the average height of the surrounding terrain. Another impressive structure is a large scarp, a cliff with a steep slope, on the right side of this image. The scarp bounds part of the south polar depression, and the Dawn team’s scientists believe features around its base are probably the result of landslides.

Mountain on Vesta

It appears the light gravity on Vesta allows for the formation of extreme topology.

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Exploring an abandoned mine in Nevada

8:01 pm

An evening pause: From the youtube webpage:

This inclined shaft is located outside of Searchlight, NV. The shaft itself is about 350 feet deep with two extensive drift levels along its length. We found a winze [a vertical shaft] in the lowest drift level that went down to what appeared to be an additional level.

I must emphasize that mines are very dangerous, and should be approached with great care and caution. Unlike a cave, which has had eons to slowly establish its stable structure, a mine is cut into the rock instantly (compared to geological time), and is thus very unstable and prone to collapse.

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The rover Opportunity as seen from Mars orbit

11:10 am

Opportunity on Endeavour Crater rim

The image to the right was taken by Mars Reconnaissance Orbiter, with the white arrow showing the Mars rover Opportunity perched on the rim of Endeavour Crater.

The rover’s scientists hope that the rocks found on the crater rim, dredged up from deep below when the crater impact occurred, will be the oldest rocks so far touched on the Martian surface, and thus give them a peek at ancient Martian geology.

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Farmers flee as Indonesia’s Mount Tambora volcano rumbles

3:32 pm

Farmers begin fleeing as Indonesia’s Mount Tambora volcano comes back alive.

Villagers like Hasanuddin Sanusi have heard since they were young how the mountain they call home once blew apart in the largest eruption ever recorded — an 1815 event widely forgotten outside their region — killing 90,000 people and blackening skies on the other side of the globe. . . . The April 1815 eruption of Tambora left a crater 7 miles (11 kilometers) wide and half a mile (1 kilometer) deep, spewing an estimated 400 million tons of sulfuric gases into the atmosphere and leading to “the year without summer” in the U.S. and Europe.

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When dust, pebbles, rocks, and boulders act like liquid

3:35 pm

The science team of Lunar Reconnaissance Orbiter released an intriguing picture yesterday of what scientists call a granular flow down the side of a five mile wide crater on the far side of the moon. Looking at the image, one would swear that the darker material flowing down the slope of the crater rim is a lava flow frozen in place.

lunar granular flow

However, according to the scientists, that is not what it is. Instead, this is merely debris left behind from an avalanche.
» Read more

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Earthquake in Virginia

2:00 pm

Quake map

A 5.9 magnitude earthquake hit Virginia at about 1:51 pm (Eastern).

I am in Maryland, just outside the beltway, and felt something like an earthquake about five minutes ago. The house started to shake, then settled, then shook again. Quite startling. I opened the front door the same time a neighbor did. She had felt the same thing.

The above quake was more than 90 miles away. I wonder how bad it is there, considering the eastern U.S. rarely experiences quakes and has made no preparations for such a thing.

For updates:
» Read more

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Craters, craters, everywhere

4:13 pm

Below the fold are two images released today, one from Dawn at Vesta and the other from Messenger at Mercury. What makes them interesting to me is that, though the surfaces of both Vesta and Mercury are crater-packed, there are definitely distinct differences between them that one can spot if you look closely, all highlighting the fundamentally different environments of both worlds.

First, the Vesta photograph. The image looks out past the asteroid’s horizon, showing clearly that this dwarf planet is not spherical, with the south pole depression that puzzles scientists just on the planet’s limb. The parallel long deep grooves that are associated with this depression can be seen on the right. Notice also that the inside walls of all the craters slope downward in a very shallow manner. This gives the impression that the impacts that formed these craters smashed into an almost beachlike sandy surface. Note too the that the center of some craters have what appear to be flat small “ponds,” a phenomenon seen by the spacecraft NEAR when it orbited the asteroid Eros. These ponds are not liquid, but are actually made up of fine-grained particles that settle in the hollows of the asteroid.
» Read more

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Endeavour Crater at last!

8:31 am

The science team for the rover Opportunity have released their first image taken from the rim of Endeavour Crater.

Since this picture looks south from Spirit Point less than a football field’s distance from the rim, it appears to look into the crater, the mountains on the right being the crater’s rim. What looks like a debris field running across the center of the image looks to me to be a combination of exposed patches of bedrock and boulders on the plateau above the rim. For the scientists, those boulders will be the prime research targets, as they are possibly ejecta produced at crater impact and could therefore be material thrown out from deep within the Martian crust.

a view of Endeavour Crater

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Nebraska rare earth mineral discovery to challenge China’s monopoly

1:46 pm

A discovery in Nebraska of rare earth minerals appears set to challenge China’s monopoly.

To me these were the key quotes from this article:

The U.S. used to produce rare earths through the Mountain Pass Mine in California, but it was shut down in 2002, primarily because of environmental concerns, including the spillage of hundreds of thousands of gallons of water carrying radioactive waste into a nearby lake.

and

Although studies have shown the U.S. has 13 million metric tons of rare-earth minerals, National Mining Association spokeswoman Carol Raulston said it does not mine any of it – partly as a result of the difficulty of obtaining permits. “One of the key problems that investors tell us about is that the permitting regime in this country is so complicated and time-consuming that it has hurt investments here in the United States,” Ms. Raulston said.

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