Tag: geology

New data says volcanoes, not asteroids, killed dinosaurs

1:38 pm

The uncertainty of science: A careful updating of the geological timeline has strengthened the link between the dinosaur extinction 66 million years ago and a major volcanic event at that time.

A primeval volcanic range in western India known as the Deccan Traps, which were once three times larger than France, began its main phase of eruptions roughly 250,000 years before the Cretaceous-Paleogene, or K-Pg, extinction event, the researchers report in the journal Science. For the next 750,000 years, the volcanoes unleashed more than 1.1 million cubic kilometers (264,000 cubic miles) of lava. The main phase of eruptions comprised about 80-90 percent of the total volume of the Deccan Traps’ lava flow and followed a substantially weaker first phase that began about 1 million years earlier.

The results support the idea that the Deccan Traps played a role in the K-Pg extinction, and challenge the dominant theory that a meteorite impact near present-day Chicxulub, Mexico, was the sole cause of the extinction. The researchers suggest that the Deccan Traps eruptions and the Chicxulub impact need to be considered together when studying and modeling the K-Pg extinction event.

The general public might not know it, but the only ones in the field of dinosaur research that have said the asteroid was the sole cause of the extinction have been planetary scientists.

5 comments

Organic material from Mars?

12:55 pm

The uncertainty of science: Scientists theorize that the carbon material found in a 2011 meteorite could be Martian biological material.

Ejected from Mars after an asteroid crashed on its surface, the meteorite, named Tissint, fell on the Moroccan desert on July 18, 2011, in view of several eyewitnesses. Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature. But they are still debating where the carbon came from.

Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint’s fissures before it left Mars.

0 comments

Italian appeals court overturns convictions of earthquake scientists

8:31 am

An Italian appeals court on Monday overturned the manslaughter convictions of six Italian earthquake scientist for the deaths of over 300 people during the L’Aquila earthquake of 2009.

Only one of the seven experts originally found guilty was convicted today: Bernardo De Bernardinis, who in 2009 was deputy head of Italy’s Civil Protection Department and who will now serve 2 years in jail, pending any further appeals.

De Bernardinis had been the guy who had publicly said that the swarm of tremors prior to the quake had released energy and thus reduced the chance of an earthquake, a claim that geology scientists do not support.

1 comment

A geological score for Curiosity!

10:25 pm

Spectroscopy from Curiosity’s most recent drilling has been found to match and thus confirm the spectroscopy of the same spot taken years ago from orbit.

In observations reported in 2010, before selection of Curiosity’s landing site, a mineral-mapping instrument on NASA’s Mars Reconnaissance Orbiter provided evidence of hematite in the geological unit that includes the Pahrump Hills outcrop. The landing site is inside Gale Crater, an impact basin about 96 miles (154 kilometers) in diameter with the layered Mount Sharp rising about three miles (five kilometers) high in the center.

“We’ve reached the part of the crater where we have the mineralogical information that was important in selection of Gale Crater as the landing site,” said Ralph Milliken of Brown University, Providence, Rhode Island. He is a member of Curiosity’s science team and was lead author of that 2010 report in Geophysical Research Letters identifying minerals based on observations of lower Mount Sharp by the orbiter’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). “We’re now on a path where the orbital data can help us predict what minerals we’ll find and make good choices about where to drill. Analyses like these will help us place rover-scale observations into the broader geologic history of Gale that we see from orbital data.”

This is a significant finding. Not only does this data now prove that the orbital data is correct, it demonstrates that scientists can now use that orbital data to direct Curiosity to even more interesting geological surface features. In fact, this ground-based data will help them calibrate all their orbital data more precisely, thus making our geological knowledge of Mars more accurate and reliable.

0 comments

How a big impact gave Vesta its grooves

3:30 pm

New data suggests that when a large impact hit Vesta’s Rheasilvia basin sometime in the past, the entire asteroid was shaken up, producing ripples that eventually surfaced as the giant grooves that circle the asteroid’s equator.

“Vesta got hammered,” said Peter Schultz, professor of earth, environmental, and planetary sciences at Brown and the paper’s senior author. “The whole interior was reverberating, and what we see on the surface is the manifestation of what happened in the interior.”

The research suggests that the Rheasilvia basin on Vesta’s south pole was created by an impactor that came in at an angle, rather than straight on. But that glancing blow still did an almost unimaginable amount of damage. The study shows that just seconds after the collision, rocks deep inside the asteroid began to crack and crumble under the stress. Within two minutes major faults reached near the surface, forming deep the canyons seen today near Vesta’s equator, far from the impact point.

Essentially, for a very very short period of time, immediately after the impact, the solid material of the asteroid acted more like a liquid, producing ripples that immediately settled down as the solid deep equatorial grooves we see today.

0 comments

Snowcaps of metal on Venus?

10:32 am

A new look at old data of Venus has added weight to the theory that the planet’s higher elevations are coated with a frost of heavy metals.

The research not only confirmed a radar brightening at higher altitudes, thus suggesting a frost coating of some kind, it also showed many dark spots whose cause remains completely unknown. As the article notes,

Years ago it was proposed that some sort of ferro-electric compound might be the cause of the brightening and the dark spots, but so far no specific compound has been identified which does the trick. Then again, with the surface of Venus being at almost 900 °F (500 °C) under more than 90 times the air pressure of Earth’s atmosphere at sea level, with occasional showers of acid, it’s not easy to test the properties of materials under Venusian conditions. “No one knows what explains the sudden darkness,” said Harrington, who will be presenting the work at the meeting of the Geological Society of America in Vancouver, B.C., on Monday, Oct. 20.

0 comments

Finding a meteorite 20 years after it hit the ground

8:32 am

By reanalyzing the data that had recorded the fireball twenty years ago, a team of meteorite hunters in the Czech Republic have finally located the remains of a meteorite that landed in 1991 but could not be found.

What is most interesting scientifically about their find is that the pieces they found were from different types of meteorites.

[T]hese four meteorites are of three different mineralogical types. This means that the Benešov meteoroid was heterogeneous and contained at least three different types of material. After the Almahata Sitta fall, this is the second time that such a heterogeneous composition has been found. It raises the possibility that a significant fraction of all asteroids are heterogeneous and that they were strongly reprocessed by collisions with other asteroids in the main belt.

In other words, the meteorite had been a conglomerate of different geological types, which were created in different environments and were later smashed together to form this one rock.

0 comments

Recent volcanism on the Moon

4:53 pm

New data from Lunar Reconnaissance Orbiter suggests that lunar volcanism petered out slowly and occurred more recently that previously believed.

NASA’s Lunar Reconnaissance Orbiter (LRO) has provided researchers strong evidence the moon’s volcanic activity slowed gradually instead of stopping abruptly a billion years ago. Scores of distinctive rock deposits observed by LRO are estimated to be less than 100 million years old. This time period corresponds to Earth’s Cretaceous period, the heyday of dinosaurs. Some areas may be less than 50 million years old. Details of the study are published online in Sunday’s edition of Nature Geoscience. “This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the moon,” said John Keller, LRO project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

In a way, this new conclusion is an example of science discovering the obvious. It seems to me quite unlikely that volcanic activity on the Moon would have “stopped abruptly” under any conditions. That’s not how these things work.

2 comments

Death Valley’s moving rocks

6:01 pm

An evening pause: The detective story that solved the mystery of the moving rocks of Death Valley.

For a century, these eerie rocks and their long, graceful trails have stumped visitors and scientists. The boulders of black dolomite appear to move on their own, sliding uphill across the playa’s flat lakebed. The trails are the only evidence the rocks move. No one has ever seen them set sail.


0 comments
1 … 136 137 138 139 140 … 157