Message #173447

[Adam Hawthorne]

(Page 2 of 2)

"Many of us think Dallas is really onto something," Ryan said. "She is building a story just like Walter Alvarez did." Alvarez, a professor of earth and planetary sciences at the University of California, Berkeley, spent a decade convincing skeptics that a giant asteroid wiped out the dinosaurs 65 million years ago.

Ted Bryant, a geomorphologist at the University of Wollongong in New South Wales, Australia, was the first person to recognize the palm prints of mega-tsunamis. Large tsunamis of 30 feet or more are caused by volcanoes, earthquakes and submarine landslides, he said, and their deposits have different features.

Deposits from mega-tsunamis contain unusual rocks with marine oyster shells, which cannot be explained by wind erosion, storm waves, volcanoes or other natural processes, Bryant said.

"We're not talking about any tsunami you're ever seen," Bryant said. "Aceh was a dimple. No tsunami in the modern world could have made these features. End-of-the-world movies do not capture the size of these waves. Submarine landslides can cause major tsunamis, but they are localized. These are deposited along whole coastlines."

For example, Bryant identified two chevrons found over four miles inland near Carpentaria in north central Australia. Both point north. When Abbott visited a year ago, he asked her to find the craters.

To locate craters, Abbott uses sea surface altimetry data. Satellites scan the ocean surface and log the exact height of it. Underwater mountain ranges, trenches and holes in the ground disturb the Earth's gravitational field, causing sea surface heights to vary by fractions of an inch. Within 24 hours of searching the shallow water north of the two chevrons, Abbott found two craters.

Not all depressions in the ocean are impact craters, Abbott said. They can be sink holes, faults or remnant volcanoes. A check is needed. So she obtained samples from deep sea sediment cores taken in the area by the Australian Geological Survey.

The cores contain melted rocks and magnetic spheres with fractures and textures characteristic of a cosmic impact. "The rock was pulverized, like it was hit with a hammer," Abbott said. "We found diatoms fused to tektites," a glassy substance formed by meteors. The molten glass and shattered rocks could not be produced by anything other than an impact, she said.

"We think these two craters are 1,200 years old," Abbott said. The chevrons are well preserved and date to about the same time.

Abbott and her colleagues have located chevrons in the Caribbean, Scotland, Vietnam and North Korea, and several in the North Sea.

Heather Hill State Park on Long Island has a chevron whose front edge points to a crater in Long Island Sound, Abbott said. There is another, very faint chevron in Connecticut, and it points in a different direction.

Marie-Agnès Courty, a soil scientist at the European Center for Prehistoric Research in Tautavel, France, is studying the worldwide distribution of cosmogenic particles from what she suspects was a major impact 4,800 years ago.

But Madagascar provides the smoking gun for geologically recent impacts. In August, Abbott, Bryant and Slava Gusiakov, from the Novosibirsk Tsunami Laboratory in Russia, visited the four huge chevrons to scoop up samples.

Last month, Dee Breger, director of microscopy at Drexel University in Philadelphia, looked at the samples under a scanning electron microscope and found benthic foraminifera, tiny fossils from the ocean floor, sprinkled throughout. Her close-ups revealed splashes of iron, nickel and chrome fused to the fossils.

When a chondritic meteor, the most common kind, vaporizes upon impact in the ocean, those three metals are formed in the same relative proportions as seen in the microfossils, Abbott said.

Breger said the microfossils appear to have melded with the condensing metals as both were lofted up out of the sea and carried long distances.

About 900 miles southeast from the Madagascar chevrons, in deep ocean, is Burckle crater, which Abbott discovered last year. Although its sediments have not been directly sampled, cores from the area contain high levels of nickel and magnetic components associated with impact ejecta.

Burckle crater has not been dated, but Abbott estimates that it is 4,500 to 5,000 years old.

It would be a great help to the cause if the National Science Foundation sent a ship equipped with modern acoustic equipment to take a closer look at Burckle, Ryan said. "If it had clear impact features, the nonbelievers would believe," he said.

But they might have more trouble believing one of the scientists, Bruce Masse, an environmental archaeologist at the Los Alamos National Laboratory in New Mexico. He thinks he can say precisely when the comet fell: on the morning of May 10, 2807 B.C.

Masse analyzed 175 flood myths from around the world, and tried to relate them to known and accurately dated natural events like solar eclipses and volcanic eruptions. Among other evidence, he said, 14 flood myths specifically mention a full solar eclipse, which could have been the one that occurred in May 2807 B.C.

Half the myths talk of a torrential downpour, Masse said. A third talk of a tsunami. Worldwide they describe hurricane force winds and darkness during the storm. All of these could come from a mega-tsunami.

Of course, extraordinary claims require extraordinary proof, Masse said, "and we're not there yet."