Posted on 03/14/2006 5:40:39 PM PST by blam
Geologist Wins Top Science Award
March 6, 2006 10:00 p.m. EST
Yvonne Lee - All Headline News Staff Reporter
Reno, Nevada (AHN) - Geologist Walter Alvarez will receive the Desert Research Institute's silver medallion and a $20,000 prize.
The Associated Press reports the University of California-Berkeley scientist came up with the theory that dinosaurs were killed off when a comet or asteroid crashed into the Earth.
President of the institute Stephen G. Wells says, "Until the impact theory was finally proven, Dr. Alvarez and his colleagues were regarded as heretics by the `old guard' in the field of geology."
In the 1970s, Alvarez and his team found high levels of Iridium in Italy. The element is exceedingly rare on Earth, but is common in asteroids and comets.
They proposed a theory that said a giant asteroid crashed into the Earth and spewed smoke, dust and iridium into the sky. This blocked the sun and lowered the Earth's temperature, which killed plants and animals.
Few scientists supported his theory when it was published in the journal Science in 1980.
However, evidence of an enormous impact crater found in Mexico's Yucatan Peninsula in 1989 changed some minds.
Ping.
When?
The asteroid hit ~65 million years ago in what is now the Yucatan peninsula.
They proposed a theory that said a giant asteroid crashed into the Earth and spewed smoke, dust and iridium into the sky. This blocked the sun and lowered the Earth's temperature, which killed plants and animals.
When?
Well, it had to be in the last 2000 years cause "mexico" didn't exist before then.
Probably why burritos give people gas, all those dinosaurs
chopped up and sitting in a freezer for a thousand years.
Actually this is wonderful news, finally recognition for
a lot of hard work.
He's a nice, likeable guy too.
I just took a look at this month's archives. Someone posted this announcement on the Dinosaur List on March 6, and one of the list members, Gautam Majumdar, pointed out that M. W. De Laubenfels had proposed an impact as the cause of the KT boundary mass extinction back in 1956 already.
Another list member linked to a press release from the University of Leicester about the work of two geologists at that university who argue for volcanism rather than an extraterrestrial impact as the cause of the mass extinctions. (The press release is entitled "Mass Extinctions -- A Threat from Outer Space or Our Own Planet's Detox?")
You are correct, I got them mixed up and in fact have been thinking of Luis.
*groan*
Well deserved. I hope he uses some of that money to drink a toast to his dad the late Luis Alvarez who was instrumental to that find.
In Walter's book "T-Rex and the Crater of Doom" he has one of my favorite opening lines; "65 million years ago the Earth had a bad day".
M. W. De Laubenfels had proposed an impact as the cause of the KT boundary mass extinction back in 1956 already.That's interesting, I'm not sure I'd read that before. The Alvarez theory came to public attention circa 1980; an earlier attempt to use large impact as an explanation for the Great Dying was published in 1970 by someone else, and fell into the void. Pemex identified the crater in 1960 (!) without consideration of the origin or any connection with extinctions, and one of the Pemex geologists pointed it out to Luis circa 1980 -- without getting any response. The Chicxulub crater was finally fingered in 1990. The important role of impact wasn't finally victorious (and it has been victorious, despite the claims of some carpers among volcanologists) until 1994, when SL-9's fragments crashed one by one into Jupiter.
Asteroids:
Deadly Impact
National GeographicRain of Iron and Ice:
The Very Real Threat of
Comet and Asteroid Bombardment
by John S. Lewis
Plot of the Innermost Solar System
Minor Planet Center
http://cfa-www.harvard.edu/iau/lists/InnerPlot2.html
Night Comes to the Cretaceous[W]ith no generally accepted explanation for the dinosaurs' sudden demise, there was no broad, unified defense of an alternative to the Alvarez proposal. Nevertheless, as Powell documents, it was no easy road to acceptance of the idea, especially among paleontologists. One prominent astronomer even argued against the impact hypothesis... Powell finally realizes that the burden of proof has shifted to the anti-impactors... This is a well-written, intelligent book, accessible to the interested layperson but also fully footnoted for geoscientists who want more technical details. It is a thorough account of that portion of the K-T battle, now won, that was fought on a geological turf.
by James Lawrence Powell
reviewed Nov. 24, 1998
by Clark R. Chapman
Night Comes to the Cretaceous
by James Lawrence Powell
The Earth may have been smooth as a cue ball though:Scientists Confirm Age Of The Oldest Meteorite Collision On EarthThe meteorite that led to the dinosaur extinction produced spherule deposits around the world that are less than 2 centimeters deep. But the spherule beds in South Africa and Australia are much bigger -- some 20 to 30 centimeters thick. A chemical analysis of the rocks also has revealed high concentrations of rare metals such as iridium -- rare in terrestrial rocks but common in meteorites...
Stanford University
He and his colleagues point to evidence showing that, 3.5 billion years ago, Earth was mostly covered with water.This very early impact wasn't the last:
In addition to the 3.47-billion-year-old impact, Lowe and Byerly have found evidence of meteorite collisions in three younger rock layers in the South African formation. According to Lowe, the force of those collisions may have been powerful enough to cause the cracks -- or tectonic plates -- that riddle the Earth's crust today.The cracks (not plates) have extraterrestrial causes.
He also pointed to uncertainty among scientists about what the climate of the Archean Earth was really like. In a forthcoming study, Lowe will present evidence that the average temperature of the planet back then was very hot -- perhaps 185 F (85 C).Was the much higher temperature due to the energy of the impact (duh!)? Or is this just another excuse to shill about the effect of so-called greenhouse gases?
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