[meteorite-list] Latest from Gerta Keller - Chixilub didn't really do it...
Not sure how much I agree with all this, but it sures seems the end Cretaceous would have been a bad time to be on planet Earth. One-Two Punch Caused Mass Extinction November 18, 2011 Princeton Univ. researchers found that massive, prolonged eruptions of the Deccan Traps in India gradually eliminated species and resulted in the Cretaceous-Tertiary mass extinction that killed the dinosaurs 65 million years ago. Marine sediment trapped between Deccan lava flows revealed that a species known as planktonic foraminifera-widely used to gauge the severity of prehistoric disasters-succumbed to lava mega-flows and volcano-induced environmental stress such as acid rain and drastic climate changes. As conditions on Earth worsened, large, variedspecies (left) were eliminated. The no more than seven or eight smaller species (right) that remained dwarfed further. Image: Gerta Keller A cosmic one-two punch of colossal volcanic eruptions and meteorite strikes likely caused the mass-extinction event at the end of the Cretaceous period that is famous for killing the dinosaurs 65 million years ago, according to two Princeton Univ. reports that reject the prevailing theory that the extinction was caused by a single large meteorite. Princeton-led researchers found that a trail of dead plankton spanning half a million years provides a timeline that links the mass extinction to large-scale eruptions of the Deccan Traps, a primeval volcanic range in western India that was once three-times larger than France. A second Princeton-based group uncovered traces of a meteorite close to the Deccan Traps that may have been one of a series to strike the Earth around the time of the mass extinction, possibly wiping out the few species that remained after thousands of years of volcanic activity. Researchers led by Princeton professor of Geosciences Gerta Keller report this month in the Journal of the Geological Society of India that marine sediments from Deccan lava flows show that the population of a plankton species widely used to gauge the fallout of prehistoric catastrophes plummeted nearly 100 percent in the thousands of years leading up to the mass extinction. This eradication occurred in sync with the largest eruption phase of the Deccan Traps-the second of three-when the volcanoes pumped the atmosphere full of climate-altering carbon dioxide and sulfur dioxide, the researchers report. The less severe third phase of Deccan activity kept the Earth nearly uninhabitable for the next 500,000 years, the researchers report. A substantially weaker first phase occurred roughly 2.5 million years before the second-phase eruptions. Another group based in Keller's lab found evidence in Indian sediment of a meteorite strike from the time of the mass extinction that would have been sufficient to finish off the few but weakened species that survived the Deccan eruptions, according to a report in the journal Earth and Planetary Science Letters (EPSL). This same sediment-located in Meghalaya, India, more than 600 miles east of the Deccan Traps-portrayed the Earth during this period as a harsh environment of acid rain and erratic global temperatures. Taken together, Keller says, the Princeton findings could finally put to rest the theory that the mass-extinction event-known as the Cretaceous-Tertiary, or KT, for the periods it straddles-was triggered solely by a large meteorite impact near Chicxulub in present-day Mexico. That impact -which occurred around the time of the second-phase Deccan eruptions-is thought to have been 2 million times more powerful than a hydrogen bomb and generated an enormous dust cloud and gases that radically altered the climate. Keller has long held that the Chicxulub impact was not catastrophic enough to cause the KT mass extinction-the newest work from her lab, however, shows that the largest Deccan eruptions were. Our work in Meghalaya and the Deccan Traps provides the first one-to-one correlation between the mass extinction and Deccan volcanism, says Keller, who is lead author of the Geological Society paper and second author of the EPSL paper after lead author Brian Gertsch, who earned his Ph.D. from Princeton. Gertsch is now a postdoctoral researcher at the Massachusetts Institute of Technology. We demonstrate a clear cause-and-effect relationship that these massive volcanic eruptions were far more destructive than previously thought and could have caused the KT mass extinction even without the addition of large meteorite impacts, Keller says. But given the environmental instability caused by the massive Deccan eruptions, an impact could easily have killed off the few survivor species at the end of the Cretaceous. It would have been a double whammy. Vincent Courtillot, a geophysicist and professor at Paris Univ. Diderot, says that the Princeton papers are based on a closer examination of Deccan volcanism and its aftermath than has been conducted previously. As such, he says, the researchers'
Re: [meteorite-list] Latest from Gerta Keller - Chixilub didn't really do it...
Hi David and List, Interesting theory. I am a little confused at what this new research is trying to say. Are they claiming that the volcanism from the Deccan Traps is largely responsible for the mass extinctions and that the coincidental meteorite impact aggravated the problem? Or, are they claiming that a meteorite impact near the area of the Deccan Traps triggered the resulting volcanism? It is not inconceivable to think that the latent potential of the Deccan Traps was unleashed by a catastrophic meteorite impact that punctured the crust and released the volcanism that caused the extinctions? In effect, this would mean that the Deccan Traps would not have caused the extinctions on their own, because the volcanism would not have been triggered if the meteorite impact had not happened. Considering the massive size and global cataclysmic effects caused by the Chicxulub event, it is hard to imagine that such an impact could not have caused the extinctions on it's own without any help from unrelated volcanism. However, if the Deccan Traps were already pummeling life on Earth with it's toxic effects, then the subsequent Chicxulub event may have been the knock out punch that finished off the species that were already on the ropes from the Deccan volcanism. Either way, the new research still admits that a meteorite impact played a role - even if it was secondary. Best regards, MikeG -- - Galactic Stone Ironworks - Meteorites Amber (Michael Gilmer) Website - http://www.galactic-stone.com Facebook - http://tinyurl.com/42h79my News Feed - http://www.galactic-stone.com/rss/126516 Twitter - http://twitter.com/galacticstone - On 11/18/11, David R. Vann drv...@sas.upenn.edu wrote: Not sure how much I agree with all this, but it sures seems the end Cretaceous would have been a bad time to be on planet Earth. One-Two Punch Caused Mass Extinction November 18, 2011 Princeton Univ. researchers found that massive, prolonged eruptions of the Deccan Traps in India gradually eliminated species and resulted in the Cretaceous-Tertiary mass extinction that killed the dinosaurs 65 million years ago. Marine sediment trapped between Deccan lava flows revealed that a species known as planktonic foraminifera-widely used to gauge the severity of prehistoric disasters-succumbed to lava mega-flows and volcano-induced environmental stress such as acid rain and drastic climate changes. As conditions on Earth worsened, large, variedspecies (left) were eliminated. The no more than seven or eight smaller species (right) that remained dwarfed further. Image: Gerta Keller A cosmic one-two punch of colossal volcanic eruptions and meteorite strikes likely caused the mass-extinction event at the end of the Cretaceous period that is famous for killing the dinosaurs 65 million years ago, according to two Princeton Univ. reports that reject the prevailing theory that the extinction was caused by a single large meteorite. Princeton-led researchers found that a trail of dead plankton spanning half a million years provides a timeline that links the mass extinction to large-scale eruptions of the Deccan Traps, a primeval volcanic range in western India that was once three-times larger than France. A second Princeton-based group uncovered traces of a meteorite close to the Deccan Traps that may have been one of a series to strike the Earth around the time of the mass extinction, possibly wiping out the few species that remained after thousands of years of volcanic activity. Researchers led by Princeton professor of Geosciences Gerta Keller report this month in the Journal of the Geological Society of India that marine sediments from Deccan lava flows show that the population of a plankton species widely used to gauge the fallout of prehistoric catastrophes plummeted nearly 100 percent in the thousands of years leading up to the mass extinction. This eradication occurred in sync with the largest eruption phase of the Deccan Traps-the second of three-when the volcanoes pumped the atmosphere full of climate-altering carbon dioxide and sulfur dioxide, the researchers report. The less severe third phase of Deccan activity kept the Earth nearly uninhabitable for the next 500,000 years, the researchers report. A substantially weaker first phase occurred roughly 2.5 million years before the second-phase eruptions. Another group based in Keller's lab found evidence in Indian sediment of a meteorite strike from the time of the mass extinction that would have been sufficient to finish off the few but weakened species that survived the Deccan eruptions, according to a report in the journal Earth and Planetary Science Letters (EPSL). This same sediment-located in Meghalaya, India, more than 600 miles east of the Deccan
Re: [meteorite-list] Latest from Gerta Keller - Chixilub didn't really do it...
The truth is but a resting place until the next revelation; http://www.youtube.com/watch?v=pOxZgn-wtc0 Carl meteoritemax -- Cheers Galactic Stone Ironworks meteoritem...@gmail.com wrote: Hi David and List, Interesting theory. I am a little confused at what this new research is trying to say. Are they claiming that the volcanism from the Deccan Traps is largely responsible for the mass extinctions and that the coincidental meteorite impact aggravated the problem? Or, are they claiming that a meteorite impact near the area of the Deccan Traps triggered the resulting volcanism? It is not inconceivable to think that the latent potential of the Deccan Traps was unleashed by a catastrophic meteorite impact that punctured the crust and released the volcanism that caused the extinctions? In effect, this would mean that the Deccan Traps would not have caused the extinctions on their own, because the volcanism would not have been triggered if the meteorite impact had not happened. Considering the massive size and global cataclysmic effects caused by the Chicxulub event, it is hard to imagine that such an impact could not have caused the extinctions on it's own without any help from unrelated volcanism. However, if the Deccan Traps were already pummeling life on Earth with it's toxic effects, then the subsequent Chicxulub event may have been the knock out punch that finished off the species that were already on the ropes from the Deccan volcanism. Either way, the new research still admits that a meteorite impact played a role - even if it was secondary. Best regards, MikeG -- - Galactic Stone Ironworks - Meteorites Amber (Michael Gilmer) Website - http://www.galactic-stone.com Facebook - http://tinyurl.com/42h79my News Feed - http://www.galactic-stone.com/rss/126516 Twitter - http://twitter.com/galacticstone - On 11/18/11, David R. Vann drv...@sas.upenn.edu wrote: Not sure how much I agree with all this, but it sures seems the end Cretaceous would have been a bad time to be on planet Earth. One-Two Punch Caused Mass Extinction November 18, 2011 Princeton Univ. researchers found that massive, prolonged eruptions of the Deccan Traps in India gradually eliminated species and resulted in the Cretaceous-Tertiary mass extinction that killed the dinosaurs 65 million years ago. Marine sediment trapped between Deccan lava flows revealed that a species known as planktonic foraminifera-widely used to gauge the severity of prehistoric disasters-succumbed to lava mega-flows and volcano-induced environmental stress such as acid rain and drastic climate changes. As conditions on Earth worsened, large, variedspecies (left) were eliminated. The no more than seven or eight smaller species (right) that remained dwarfed further. Image: Gerta Keller A cosmic one-two punch of colossal volcanic eruptions and meteorite strikes likely caused the mass-extinction event at the end of the Cretaceous period that is famous for killing the dinosaurs 65 million years ago, according to two Princeton Univ. reports that reject the prevailing theory that the extinction was caused by a single large meteorite. Princeton-led researchers found that a trail of dead plankton spanning half a million years provides a timeline that links the mass extinction to large-scale eruptions of the Deccan Traps, a primeval volcanic range in western India that was once three-times larger than France. A second Princeton-based group uncovered traces of a meteorite close to the Deccan Traps that may have been one of a series to strike the Earth around the time of the mass extinction, possibly wiping out the few species that remained after thousands of years of volcanic activity. Researchers led by Princeton professor of Geosciences Gerta Keller report this month in the Journal of the Geological Society of India that marine sediments from Deccan lava flows show that the population of a plankton species widely used to gauge the fallout of prehistoric catastrophes plummeted nearly 100 percent in the thousands of years leading up to the mass extinction. This eradication occurred in sync with the largest eruption phase of the Deccan Traps-the second of three-when the volcanoes pumped the atmosphere full of climate-altering carbon dioxide and sulfur dioxide, the researchers report. The less severe third phase of Deccan activity kept the Earth nearly uninhabitable for the next 500,000 years, the researchers report. A substantially weaker first phase occurred roughly 2.5 million years before the second-phase eruptions. Another group based in Keller's lab found evidence in Indian sediment of a meteorite strike from the time of
