Tag: geology

News from Mars: Laser-Blasting and Soil Sampling

mars_lifeAs the exploration of Mars goes on, the small army of robotic rovers, satellites and orbiters continue to provide us with information, photographs and discoveries that remind us of how great a mystery the Red Planet truly is. For instance, in the past month, two major stories have been announced concerning the nature of Martian soil, its ancient history, and some of the more exciting moments in it’s exploration.

For example, Curiosity made news as its high resolution camera caught an image of sparks being generated as it zapped a Martian rock. In it’s lifetime, the rover has used its million watt Chemistry and Camera (ChemCam) laser to zap over 600 rock or soil targets as part of its mission. However, this was the first time that the rover team was able to get the arm-mounted Mars Hand Lens Imager (MAHLI) to capture the action as it occurred.

Curiosity-Laser-BeamThe ChemCam laser is used to determine the composition of Martian rocks and soils at a distance of up to 8 meters (25 feet). By hitting targets with several high-energy pulses, it is able to yield preliminary data for the scientists and engineers back at Earth to help them decide if a target warrants a closer investigation and, in rare cases, sampling and drilling activities.

ChemCam works through a process called laser-induced breakdown spectroscopy. The laser hits a target with pulses to generate sparks, whose spectra provide information about which chemical elements are in the target. Successive laser shots are fired in sequence to gradually blast away thin layers of material. Each shot exposes a slightly deeper layer for examination by the ChemCam spectrometer.

Mars_novarockAs Curiosity fired deeper into the target rock – named “Nova” – it showed an increasing concentration of aluminum as the sequential laser blasts penetrated through the uninteresting dust on the rock’s surface. Silicon and sodium were also detected. As Sylvestre Maurice, ChemCam’s Deputy Principal Investigator at the Research Institute in Astrophysics and Planetology, said in a statement:

This is so exciting! The ChemCam laser has fired more than 150,000 times on Mars, but this is the first time we see the plasma plume that is created… Each time the laser hits a target, the plasma light is caught and analyzed by ChemCam’s spectrometers. What the new images add is confirmation that the size and shape of the spark are what we anticipated under Martian conditions.

During it’s first year on Mars, Curiosity has already accomplished its primary objective of discovering a habitable zone on Mars that contains the minerals necessary to support microbial life billions of years ago when Mars was wetter and warmer. Currently, the rover is driving swiftly to the base of Mount Sharp at the center of Gale Crater, where it hopes to find more.

Mars_soilIn that same vein, according to new geological information obtained by Curiosty’s images and soil examinations, samples that were pulled out of a crater that is estimated to be some 3.7 billion years old contain more evidence that Mars was once much warmer and wetter. These findings were announced in a recent paper published in the online edition of Geology by University of Oregon geologist Gregory Retallack.

Unlike Earth, the Martian landscape is littered with loose rocks from impacts or layered by catastrophic floods. However, recent images from Curiosity from the Gale Crater reveal Earth-like soil profiles with cracked surfaces lined with sulfate, ellipsoidal hollows and concentrations of sulfate comparable with soils in Antarctica’s McMurdo Dry Valleys and Chile’s Atacama Desert.

mars-180-degrees-panorama_croppedRetallack, the paper’s lone author, studied mineral and chemical data published by researchers closely tied with the Curiosity mission. As a professor of geological sciences and co-director of paleontology research at the UO Museum of Natural and Cultural History, he internationally known as an expert on the recognition of paleosols – ancient fossilized soils contained in rocks.

As he explains in the paper:

The pictures were the first clue, but then all the data really nailed it. The key to this discovery has been the superb chemical and mineral analytical capability of the Curiosity Rover, which is an order of magnitude improvement over earlier generations of rovers. The new data show clear chemical weathering trends, and clay accumulation at the expense of the mineral olivine, as expected in soils on Earth. Phosphorus depletion within the profiles is especially tantalizing, because it attributed to microbial activity on Earth.

dryvalleysThe ancient soils do not prove that Mars once contained life, but they do add to growing evidence that an early, wetter and warmer Mars was more habitable than the planet has been in the past 3 billion years. Surface cracks in the deeply buried soils suggest typical soil clods. Vesicular hollows, or rounded holes, and sulfate concentrations, he said, are both features of desert soils on Earth.

Since Curiosity is currently on its way to Mount Sharp, future missions will be needed to fully explore these features. But as Retallack explained, the parallels with Earth are quite exciting:

None of these features is seen in younger surface soils of Mars. The exploration of Mars, like that of other planetary bodies, commonly turns up unexpected discoveries, but it is equally unexpected to discover such familiar ground.

The newly discovered soils indicate that more benign and habitable soil condition existed on Mars than previously expected. What’s more, their dating to 3.7 billion years ago places them within a transition period when the planet went from an early, benign water cycle to the acidic and arid Mars of today. This is especially important since major changes were taking place on Earth at around the same time.

Living-Mars.2Roughly 3.5 billion years ago, life on Earth is believed to have emerged and began diversifying. But some scientists have theorized that potential evidence that might indicate that life existed on Earth earlier may have been destroyed by tectonic activity, which did not occur on Mars. Basically, it may offer some credence to the theory that while flourished on Earth, it originated on Mars.

One person who supports this theory is Steven Benner of the Westheimer Institute of Science and Technology in Florida.  In the past, he has speculated that life is more likely to have originated on a soil planet like Mars than a water planet like Earth. In an email interview with Science Daily, Benner wrote that Retallack’s paper:

[S]hows not only soils that might be direct products of an early Martian life, but also the wet-dry cycles that many models require for the emergence of life.

So in addition to shedding light on the mysteries of Mars, Curiosity has also been pivotal in addressing some major questions which only increase the mystery of our own existence. Did life as we know it originate on Mars but flourish on Earth? Are there still some remnants of this microbial “Eden” being preserved deep within the soil and rocks? And could life exist there again some day?

All good questions that will no doubt keep robotic rovers, orbiters, landers, and even manned missions busy for many decades to come! In the meantime, check out the video from NASA’s Jet Propulsion Laboratory of Curiosity’s spark-generating laser blast being caught on tape:


Sources: universetoday.com, sciencedaily.com

News From Space: Ancient Meteorite Crater Found

meteorIn southern Alberta, scientists have found a vast, ancient crater that they claim dates back some 50 to 70 million years. Discovered entirely by accident in near the hamlet of Bow City, some 20 km south-west of Brooks, and 100 km south-east of Calgary. According to assessments of the impact zone, researchers estimate that the space rock would have been the size of an apartment block, and would have left a crater 8 kilometers wide and roughly 2 and half km deep.

All told, this explosive force of this impact would have been 200 times stronger than the most powerful thermonuclear bomb ever built. That’s basically a force of 1000 megatons, a detonation so powerful that anything within 200 km of the impact would have received 1st-degree burns. To put that in perspective, this means that the city of Calgary would have been decimated by the blast, and in Edmonton, some 400 km away, every window would shattered.

alta-meteorite-crater-20140507But even more awe inspiring was the long-term effects of the damage, which would have thrown enough dust and debris into the atmosphere to mess with the Earth’s climate for the next few years. As Schmitt put it:

Something of that size, throwing that much debris in the air, potentially would have global consequences; there could have been ramifications for decades.

But after eons of erosion, very little of the crater is left. In fact, the discovery happened entirely by accident when a geologist – who was doing some routine mapping of the underground layers a few meters beneath the surface – apparently noticed a circular disturbance that was covered. Schmitt and his lab were called in to inspecting the feature and used seismic data to create a complete image of it. They quickly realized that it was most likely an impact crater, complete with a central peak where the meteorite would have struck.

Alberta_craterThe size of the object can only be estimated, but assuming the meteor was composed mostly of iron, it would have had to have been between 300 and 500 meters in diameter to create a crater of this size. If the meteorite was rock, it would have had to have been a kilometre across. Schmitt said the crater is a rare opportunity to study the floor of an impact crater. His team is now looking for certain types of minerals that form only under certain conditions so as to confirm the crater is from a meteor impact.

But he doesn’t have much doubt. As he put in a recent interview with CBC news:

We’re able to get at the lower parts of (a crater) and see how rocks have been moved around… We’re pretty confident it can only be a meteorite impact. It’s pretty clear.

Once they’ve had a chance to uncover and examine the area in greater detail, a clear picture of the meteorite’s size, composition, and what lasting marks its impact left beyond the crater. This information will only contribute to our understanding of our Solar System, but of the history of our planet as well.

Sources: cbc.ca, calgarysun.com

Paleonews: Reconstructing what Dinosaurs Looked Like

dinosaur_bonesSince the first discovery of their remains was made, modern humans have struggled to reconstruct how dinosaurs lived, behaved, and even appeared. As simple as it may seem to the rest of us, paleontologists understand that bones alone do not an accurate representation make. And over the years, many theories have been advanced as to what the full, fleshy forms of dinosaurs truly looked like.

And thanks to a find made in Grand Prairie, Alberta last year, one of the richest source of dinosaur bones in the world, scientists are that much closer to getting an accurate picture as to what one candidate – Edmontosaurus regalis – looked like. In short, the find revealed a body part never seen before on any dinosaur –  a soft, fleshy comb on its head, similar to those found on roosters.

edmontosaurus-regalisAccording to Victoria Arbour, a University of Alberta paleontologist who co-authored the scientific paper published Thursday in the journal Current Biology, the comb constituted a “structure that was completely unexpected.” And that it “kind of makes us wonder what other dinosaurs might have had.” The find is also interesting because of the connection it draws to the biology of today’s animals, something which is still considered distinct from prehistoric creatures.

Edmontosaurus are a duck-billed, plant-eating dinosaur that grew to be 12 metres long and was thought to have roamed North America in herds during the late Cretaceous, about 75 and 65 million years ago. It also belonged to a group of dinosaurs known as hadrosaurs, a family of duck-billed herbivores which were the most common dinosaurs on the continent at the time.

edmontosaurusPhil Bell, a paleontologist at the University of New England in Armidale, Australia, was with the Philip J. Currie Dinosaur Museum currently under construction in Grand Prairie, Alta., when he uncovered the fossil last summer with geologist Federico Fanti of the University of Bologna. As the lead author of the paper, Bell claims that the new findings are a major breakthrough in determining the dinosaur’s behavior.

In particular, the existence of the comb adds to evidence that Edmontosaurus was a social animal, as ornaments like combs and crests are typically used for communication among animals such as roosters, especially in relation to competition for females:

[E]quivalent to discovering for the first time that elephants had trunks. These findings dramatically alter our perception of the appearance and behaviour of this well-known dinosaur. We might imagine a pair of  male Edmontosaurus sizing each other up, bellowing, and showing off their head gear to see who was the dominant male and who is in charge of the herd.

dinosaur_fossilsAnd of course, this find demonstrates many of the limitations imposed on paleontologist, as fossils typically only preserve the bones of an animal and not fleshy structures. But in rare cases, fossils are found that are described as “mummified”, where bones are in the same positions relative to each other that they would have been in life, with impressions of the skin preserved on top.

According to Arbour, it’s not clear what conditions lead the preservation of skin impressions, but it likely involves the animals dying in a flood and being quickly buried by sand or mud. She added that even when skin impressions are preserved, they are often only visible in certain lighting or when the rock breaks a certain way, which may be why combs hadn’t been noticed on earlier “mummified” Edmontosaurus fossils.

dinosaur_skinimpressionsWhile earlier hadrosaurs had bony crests, researchers thought the crest had been completely lost in Edmontosaurus. The new discovery suggests that, in fact, the dinosaurs’ crests had changed, but remained an important feature. Bell said it also suggests that similar structures may have been missed in other dinosaurs:

There’s no reason that other strange fleshy structures couldn’t have been present on a whole range of other dinosaurs, including T. rex or Triceratops.

So really, this single find could have far-reaching implications for the field of paleontology. And with time, more discoveries, and additional refinements to the excavation process, we might just get a full and complete picture of what life really and truly looked like on Earth millions of years ago.

Source: cbc.ca

Curiosity Prepares to Drill

curiosity_rocksMore news from Mars! Or more specifically, from Yellowknife Bay, a place that shows extensive evidence of flowing water. After relocating to the region and performing a preliminary search, Curiosity has located the rock it will drill in order to gain an understanding of its composition and search for organics molecules. The rock has been dubbed “John Klein”, and this will be the first time engineers have drilled into the surface of another planet.

Already, Curiosity has determined that at one time, the Gale Crater was once the site of flowing water. But in its current location, they are able to assess the geological history and have stumbled upon a number of interesting features. In the course of descending from the plateau region where it landed into the relative depression that is Yellowknife Bay, Curiosity has observed many layers of rock that are increasingly older, effectively taking it backwards into the planet’s history.

Curiosity-Yellowknife-Bay-Sol-125_2c_Ken-Kremer-580x151Geologists are finding a lot of different rock types, indicating that many different geologic processes took place here over time, all of which confirm that water passed through the region at one time. For example, some of the minerals are sedimentary, which suggests that flowing water moved small grains around and deposited them. Other samples are cracked and filled with veins of material such as calcium sulfate, which were formed when water percolated through the cracks and deposited the mineral.

terraformingAll these investigations suggest if you could go deep into Mars’ past and stand at the same spot as the rover, you’d probably see a river of flowing water with small underwater dunes along the riverbed. And since these rivers left traces behind, drilling into the rocks will reveal what else they carried, which could very well include the building blocks of life!

Already, Curiosity brushed some of these rocks to remove their dust covering and then examined them with its high-resolution Mars Hand Lens Imager (MAHLI) camera. The next step will be to drill 5 centimeter holes into some of these rocks and veins to definitively determine their composition. Geologist John Grotzinger of Caltech said that the team will search for aqueous minerals, isotope ratios that could indicate the composition of Mars’ atmosphere in the past, and possibly organic material.

curiosity_drillingThe drilling will probably take place within two weeks, though NASA engineers are still unsure of the exact date. But, says Richard Cook, Curiosity’s project manager, the procedure will be “the most significant engineering thing we’ve done since landing,” and will require several trial runs, equipment warm-ups, and drilling a couple test holes to make sure everything works. The team wants to take things as slowly as possible to correct for any problems that may arise, such as potential electrical shorts and excessive shaking of the rover.

And of course, this time around they are likely to be much more tight-lipped and reserved when it comes to announcing their findings. Should they uncover evidence of life at one time in Mars’ deep past, they will certainly need to be sure. Such a finding is likely to be… “Earthshaking”! I admit, that’s getting old. I’ll stop now…

Source: Wired.com