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Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Posts Tagged ‘asteroid impact’

Dinosaurs Asteroid Extinction: ‘Crotch Science’

Posted by feww on March 7, 2010

Submitted by a reader:

Keep Freudian Politics Out of Science!

Dinosaur Extinction Highly Improbable as a Result of a Single Event


Barringer Crater from space. [The crater is also known as ‘Meteor Crater’ and ‘Canyon Diablo Crater.’] Barringer Crater,  is a 1,300-meter (0.8 mile) diameter, 174-meter (570-feet) deep hole in the flat-lying desert sandstones 30 kilometers (18.6 miles) west of Winslow, Arizona. Since the 1890s geologic studies here played a leading role in developing an understanding of impact processes on the Earth, the moon and elsewhere in the solar system. This view was acquired by the Landsat 4 satellite on December 14, 1982. Diablo Canyon arroyo is to the west (left). The ghost town of Diablo Canyon is on the canyon to the north and out of the picture. The bulk of the meteorite is believed to be embedded in the south side of the crater under the rim. Credit: NASA Visible Earth.

The following excerpts are from a news report by Cambridge University,  England:

Asteroid killed off the dinosaurs

“Our work lets us visualise the astonishing events of the few minutes after impact. The front of the asteroid hit the Earth while the far side was still out in the upper atmosphere [sic,] punching a hole though the Earth’s atmosphere.

[Note: Readers would recall that the asteroid is believed to have been about 10km long.]

“As the asteroid vapourised explosively, it created a crater 30 km deep and 100 km across, with sides as high as the Himalayas. However within only two minutes the sides collapsed inwards and the deepest parts of the crater rebounded upwards to leave a wide, shallow hollow.

“These terrifying events led to darkness and a global winter, resulting in the extinction of more than 70% of known species. The tiny shrew-like mammals which were around at that time proved better adapted to survival than the cumbersome dinosaurs, and the removal of these dominant animals paved the way for the radiation of the mammals and eventual emergence of humans on Earth.” — Dr Penny Barton, who led the seismic survey and a co-author of the review

Just about every single paragraph of the review, the ones available on the internet that this author has read, features a glaring improbability.


Animation showing the Chicxulub Crater impact. Credit: University of Arizona, Space Imagery Center. Click image to enlarge and animate.

Science Fiction, or Crotch Science?

The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary
Summary or Review

The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction. AAAS Review

Was the impact of 10-km bolide that formed the Chicxulub crater so catastrophic that it drove 70 percent of the world species to extinction in a short period?

The Chicxulub Paradox:

  1. The adverse environmental impact of the Chicxulub Asteroid, which lasted for a relatively short period [years,] drove dinosaurs, 70 percent of all species to extinction.
  2. Dinosaurs eventually became extinct over a relatively long period [millions of years.]

If the K-T extinction occurred as a direct result of the Chicxulub impact that led to “environmental perturbations (for example, darkness and cooling),” it must have necessarily led to a global ‘famine’ also, necessitating a rapid [and total] occurrence.

The comprehensive mechanisms needed for large-scale species extinction cannot be driven by a single event, albeit of a catastrophic magnitude, whose consequences  could have only lasted for a relatively short period.

A single catastrophic event capable of wiping off large percentage of all species, could only occur if it occurs in totality, for example, by vaporizing the ocean water, consuming the entire range of flora, extracting the air from the atmosphere, or flooding the entire planet. In that case, the remaining 50, 40, or even 30 percent of fauna, whose survival depended on the same shared resources, natural services and environmental factors, could not have survived.

Conclusion:

The environmental damage caused by the Chicxulub impact was not total, and could not have had lasting consequences, either. The planet would have recovered from the effects of the impact in a few seasons.

A plethora of evidence suggests that dinosaurs and the other 70 or so percent of the species that allegedly became extinct, did not all die off in a few short seasons.

[You cannot blame the extinction of dinosaurs on an asteroid impact, if the extinction  occurred over a period of couple of million years after the impact!]


Another View of Barringer Crater. Source: USGS

Note: Fire-Earth moderators may comment on the above at a later date.

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Last Edited: April 21 at 02:35UTC

Posted in Chicxulub asteroid, Cretaceous-Tertiary extinction, K-T extinction, mass extinction, Scripps Institution of Oceanography | Tagged: , , , , , , , , , | Leave a Comment »

Asteroid killed the Dinosaurs?

Posted by feww on March 5, 2010

Thank YOU Asteroid (!)

If indeed an asteroid impact killed off the dinosaurs, the intelligent rock performed brilliantly, wiping off only those ugly species, thus selecting what was to evolve as homo sapiens x2 and all other wonderful species, which we now are committing to extinction, to survive and thrive. —Fire-Earth

Unfortunately, the scientists have not yet explained how the intelligent asteroid’s selection criteria worked!

University of California – San Diego: Public Release

30 years later, what killed the dinosaurs is revisited

Scripps researcher among dozens making the case with new evidence that an asteroid impact caused a mass extinction 65.5 million years ago

Scripps Institution of Oceanography, UC San Diego, paleoceanographer Richard Norris is one of 41 scientists presenting evidence that an asteroid impact really did kill off dinosaurs and myriad other organisms 30 years after the theory was first proposed.


An asteroid impact 65.5 million years ago left a clear band between light colored Cretaceous sediment (left) and dark-colored, Paleocene sediment (right) recovered from the seafloor off South America. The abrupt shift in sediment color that reflects the instantaneous drop in ocean biological productivity, fossil numbers, and species. Credit: Scripps Institution of Oceanography, UC San Diego

The 15km wide asteroid is said to have struck the planet with a force of more than 100 trillion tons of TNT (6.6 billion times more powerful than the atomic bomb at Hiroshima about 65 million years ago), resulting in the famous Chicxulub crater, which is buried underneath the Yucatan Peninsula in Mexico.

The researchers are authors of a review paper being released Friday in the journal Science that represents a new salvo in an ongoing controversy over the cause of the mass extinction. Norris’ contribution to the paper was evidence in seafloor sediment records that indicate how deep-sea life was profoundly reshaped by the impact.

“The story is a lot stronger now than 30 years ago, when it was admittedly a little more speculative,” said Norris. “Since 1980, we have accumulated an overwhelming amount of evidence that there was an impact. We also think the evidence is overwhelming that there was a mass extinction as a direct result of this event.”

In that year, father and son researchers Luis and Walter Alvarez first proposed the notion that an asteroid impact killed off the dinosaurs. They had discovered that high levels of iridium, an element rare on Earth but common on extraterrestrial objects like meteors, were uniformly present in sedimentary samples that could be dated back to the extinction event, which marked the transition between two geologic periods.

At the time, they did not know where on Earth that impact might have taken place. It would be another 11 years before researchers Alan Hildebrand and Glen Penfield suggested that a crater left behind by an asteroid impact was buried on the Yucatan peninsula. With the crater nearly 200 kilometers (125 miles) in diameter, the impact was one large enough to have caused the mass extinction in agreement with the Alvarez hypothesis.

The force of the impact itself — there is evidence of giant earthquakes and tsunami waves more than 1,000 feet tall being generated in the immediate aftermath — and the following profound atmospheric changes combined to make the planet uninhabitable for between 40 and 70 percent of all life forms on Earth.

But rival explanations, though outside the mainstream, have continued to proliferate in high-profile fashion. One theory that has gained widespread attention attributes the mass extinction to a volcanic event in India that took place at roughly the same time as the impact. Another faction of researchers acknowledges that the asteroid did strike but that its effects were not enough to cause the mass extinction.

The sizes of deep sea foraminifera fossils from just after the impact (a) and immediately before the impact. The scale bar in both pictures is 500 microns (half a millimeter). Credit: Scripps Institution of Oceanography, UC San Diego

Norris notes that an inspection of ancient layers of seafloor sediment around the world show a clear record of the event contained in a red or green band composed of materials ejected from the blast. These include pieces of rock like those on the Yucatan, glassy droplets that represent melted rock, microscopic diamonds made under the very high pressures produced by the impact and meteoric debris.

“There are also monster submarine landslides along the entire East Coast of the U.S. from the massive earthquake triggered by the impact,” he said.

Norris points to several pieces of evidence from the deep sea that support a tight link between the impact and the mass extinction. In most places in the deep ocean, the impact debris layer is associated with an abrupt decrease in the size of fossils — the appearance of a dwarfed “disaster” fauna. Abrupt environmental changes throughout history such as the impact tend to favor smaller organisms that have more rapid lifecycles and fewer resource needs than larger organisms. Biological productivity plummets in many parts of the oceans immediately after the impact. The drop in productivity is partly reflected by a change in the color of deep-sea sediments — from creamy white to brown or grey — as light-colored fossil shells abruptly decreased in number.

Individually, the decrease in fossil size, the appearance of a “disaster fauna” and the plummet in ocean productivity are unusual, and together with an impact debris layer, are unique in the deep-sea sediment record.

“This is not a ‘smoking gun,'” said Norris, “it’s a ‘smoking cannon.'”

A smoking cannon that fires selectively—Fire-Earth

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Posted in Chicxulub, mass extinction, paleoceanography, volcanic event, Yucatan peninsula | Tagged: , , , , , , , | 1 Comment »

Volcanoes Killed Off Dinosaurs

Posted by feww on December 17, 2008

Researchers say volcanism more likely caused K-T extinction; not asteroid impact

Addressing the age-old question of what really happened to dinosaurs, researchers at Princeton University say they have found more evidence that it was volcanism, not an asteroid impact that killed them off.

According to the asteroid-impact theory, put forward in 1980 by physicist Luis Walter Alvarez, the Cretaceous-Tertiary extinction, or the K-T mass extinction, which killed off the dinosaurs and caused the extinction of about 70 percent of life on Earth, was caused by a massive impact.


Artist’s rendering of bolide impact. Made by Fredrik. Cloud texture from public domain NASA image.

The asteroid-impact theory is supported by Chicxulub crater in Mexico’s Yucatan Peninsula, which was discovered by geophysicist Glen Penfield, while searching for oil. The 65-million year old crater occurred about the time of the K-T event.

Other theories citing climate change and volcanism have been suggested more recently. Gerta Keller of Princeton University says her studies point the blame toward volcanism.

The Deccan Traps

An intense period of colossal volcanic eruptions, which began about 67 million years ago, earlier than the impact, was regarded as another potential culprit. The eruptions  formed the Deccan Traps in India.

The Deccan Traps formed between 60 and 68 million years ago, at the end of the Cretaceous period. The bulk of the volcanic eruption occurred at the Western Ghats (near Mumbai) some 66 million years ago. This series of eruptions may have lasted fewer than 30,000 years in total. The gases released in the process may have played a role in the Cretaceous–Tertiary extinction event, which included the extinction of the dinosaurs. [Wikipedia]

The Deccan Traps are a large igneous province located on the Deccan Plateau of west-central India (between 17-24N, 73-74E) and one of the largest volcanic features on Earth. They consist of multiple layers of solidified flood basalt that together are more than 2,000 m thick and cover an area of 500,000 km². The term ‘trap’, used in geology for such rock formations, is derived from the Swedish word for stairs (trappa, or sometimes trapp), referring to the step-like hills forming the landscape of the region.

Before the Deccan Traps region was reduced to its current size by erosion and continental drift, it is estimated that the original area covered by the lava flows was as large as 1.5 million km², approximately half the size of modern India. The present volume of directly observable lava flows is estimated to be around 512,000 km³.

The release of volcanic gases during the formation of the traps “contributed to an apparently massive global warming. Some data point to an average rise in temperature of 8 °C (14 °F) in the last half million years before the impact at Chicxulub.” [Wikipedia]

Climate Change

Extreme climate change may have been caused by both the bolide impact and the volcanic explosions; in either case  massive volumes of sulfur dioxide [creating acid rains,] dust and other particles into the atmosphere would have significantly altered the climate.

In fact, some researchers believe a combination of events may have caused the mass extinction, with the asteroid impact finalizing the event.

According to Keller, however, the asteroid-impact “theory is now facing perhaps it’s most serious challenge from the Deccan volcanism and perhaps the Chicxulub impact itself.” She said at a news conference at the annual meeting of the American Geophysical Society in San Francisco.

The Cretaceous–Tertiary extinction event, which occurred approximately 65.5 million years ago (Ma), was a large-scale mass extinction of animal and plant species in a geologically short period of time. Widely known as the K–T extinction event, it is associated with a geological signature known as the K–T boundary, usually a thin band of sedimentation found in various parts of the world. K is the traditional abbreviation for the Cretaceous Period derived from the German name Kreidezeit, and T is the abbreviation for the Tertiary Period (a historical term for the period of time now covered by the Paleogene and Neogene periods). The event marks the end of the Mesozoic Era and the beginning of the Cenozoic Era.[1] “Tertiary” being discouraged as a formal time or rock unit by the International Commission on Stratigraphy, the K-T event is now called the Cretaceous—Paleogene (or K-Pg) extinction event by many researchers. [Wikipedia]


Deccan Traps near Pune, state of Maharashtra in western India. This file is licensed under the Creative Commons Attribution 3.0 Unported License. Credit: Kppethe.

Keller and her colleagues have recently analyzed geological records in India, Mexico and Texas to  determine the time of impact and the period of volcanic activities in relation to the K-T event. Their examination of sediment layers suggests that the crater impact occurred about 300,000 years before the K-T boundary, and had little or no effects to biota.

“There is essentially no extinction associated with the impact,” Keller said.

On the other hand, the peak of the Deccan volcanic explosions seems to have occurred “just before the K-T boundary,” according to a University of Paris geophysicist, Vincent Courtillot.

After the first volcanic flow, “the species disappear; we have essentially very few left [their recovery is stalled by the two subsequent flows and] by the fourth flow, the extinction is complete,” Keller said.

Courtillot study compares the amounts of sulfur dioxide emitted to the atmosphere by various events as follows, concluding that the Deccan traps are much more likely to have caused the K-T event than the asteroid impact :

  • The 1991 Pinatubo eruption: 0.017 billion tons of sulfur dioxide (SO2)
  • The Chicxulub crater:  500 billion tons of SO2
  • The Deccan traps: 10,000 billion tons SO2.

“If there had been no impact, we think there would have been a mass extinction anyway,” Courtillot said.

Confirming Courtillot’ team and her own findings, Keller added: “Deccan volcanism is the likely culprit behind the K-T mass extinction.”

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Posted in acid rain, Chicxulub crater, Gerta Keller, Vincent Courtillot, volcanism | Tagged: , , , , | 4 Comments »