Skip to comments.Bright Idea: Ancient monster tsunami mixed fossils
Posted on 02/01/2005 6:37:34 PM PST by IllumiNaughtyByNature
A 65 million year old tsunami is still wreaking havoc in the scientific community, a New Mexico State University professor says.
The 300-foot-tall tsunami - an aftereffect of the giant meteor impact that some scientists think killed off the dinosaurs - scrambled fossils and rock and has made the event very hard to date, said Timothy Lawton, head of NMSU's geology department.
Lawton has a paper coming out about the topic in the February issue of Geology magazine.
The much-debated theory Lawton says his data supports is that the dinosaurs were killed off in a massive extinction caused by a giant meteor that crashed into the earth about 65 million years ago, forming the Chicxulub crater in Mexico's Yucatan Peninsula.
"The meteor was 10 or 11 kilometers in diameter," Lawton said. "About the size of Halley's comet. Within a few nanoseconds of impact it made a crater 40 kilometers deep. That impact generated the energy of some many millions of Hiroshima bombs. It vaporized rock, sent debris for hundreds or thousands of miles, caused a nuclear winter and giant tsunamis."
Other scientists are skeptical of the theory that the impact killed the dinosaurs, because rocks and fossils found on top of the crater predate the dinosaur extinction by 300,000 years.
"Those sediments above the crater are not scrambled at all," said Gerta Keller, a geology professor at Princeton University. "The only thing that is scrambled is the top 15 feet (of the rock that was melted during the impact). On top of that are normal marine sediments. There's just no way that pattern would happen in a tsunami."
The younger rock on top of the crater, Keller says, is far too delicately organized to have been mixed up and disturbed by a tsunami.
"If you had a tsunami then, with giant waves, you wouldn't expect to see sediment layers at the millimeter scale," Keller said. "Those sediments are not chaotic, and they date over the last half-million years of the Cretaceous period."
Still, there's other confusion that might indicate those sediments came after the dinosaur extinction, Lawton said.
The end of the Cretaceous period of the geologic time scale - dated at 65.5 million years ago plus or minus 300,000 years - is tied to the massive extinction of the dinosaurs.
"The problem is a lot of these dates are tied to fossils - which can't be dated with radioisotopes, and the uncertainty in the dating of the end of the Cretaceous and the Chicxulub crater leave the theory open to a lot of interpretations," Lawton said.
The tsunamis after the impact would have traveled more than 100 miles inland and rocks from the event have been found as far north as Waco, Texas, Lawton said.
"It's like when you watch a flash flood in a wide arroyo," Lawton said. "You get these trains of waves moving over everything and mixing everything up. This was like a really huge version of that, that just scraped everything up and moved it back into the Gulf of Mexico over days."
I think thier brains are scrambled. NO, wait, that's my brain that's scrambled.
LOL! Yes, the extinction of dinosaurs may well have been prevented-if only they had listened to the surgeon general.
Or is that the sturgeon general?
Darn those deep sea creatures-coming up and stealing all the ciggies.
Technically, if the wave was caused by something other than a geologic source, is it still a tsunami?
ahhh ha! I'll bet this tsunami is responsible for Global Warming(TM) too, by Jove!
It all fits together like Leggos!
"Technically, if the wave was caused by something other than a geologic source, is it still a tsunami?"
I believe "tsunami", (a Japanese term), means "harbor wave". I don't think it means anything else related to geology.
So it probably would not matter what it comes from
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