Re: Geologists delve into giant crater off Virginia
- From: "Nobody" <nobody@xxxxxxxxxxx>
- Date: Mon, 7 Nov 2005 21:25:55 -0500
If you like craters, a very interesting exercise is to bring up this site:
http://www.unb.ca/passc/ImpactDatabase/, along with Google Earth, and use
the coordinates from the database to zoom in on the crater sites with
Google. It is fascinating.
"Alan" <alan@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:memo.20051107182801.988A@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/11/07/MNGTOFK2H01.DTL
>
> Geologists delve into giant crater off Virginia
> Huge object blasted 6 miles into seabed 35 million years ago
>
> Michael E. Ruane, Washington Post
>
> Monday, November 7, 2005
>
> Eastville, Va. -- A white fireball 2 miles across thunders from the sky at
> 30,000 mph and crashes into the ocean off the Virginia coast. The impact
> vaporizes billions of tons of water, rips a hole in the seafloor 6 miles
> deep
> and fractures the bedrock far into the Earth.
>
> The splash is 30 miles high. Debris are lofted over the horizon and rain
> down on
> an area of 3 million square miles, as distant as the Antarctic. Towering
> tsunamis surge toward the Blue Ridge Mountains.
>
> Nearby life -- ferocious-looking sea creatures and dog-size proto-horses
> along
> the tropical shoreline -- is blasted and then swept into the abyss by the
> boiling ocean. A calamity of unimaginable scale, it is probably the most
> stupendous geological event ever on the East Coast.
>
> For more than a decade, geologists have believed that a gigantic object,
> an
> asteroid or a comet, struck the Earth north of Norfolk, Va., about 35
> million
> years ago in a cataclysmic occurrence that left behind a 53-mile-wide,
> long-buried crater.
>
> An international team of scientists, seeking clues to the origins of the
> planets, has assembled in a windblown bean field near the crater's center
> to try
> to determine, among other things, exactly what happened when the object
> struck.
>
> Since September, the team has been working with a large drilling rig that
> uses
> diamond-tipped bits and brings up core samples to bore through eons of
> sediment
> toward the floor of the crater and the place where the impactor hit,
> believed to
> be about 7,000 feet below the surface.
>
> As a farmer harvested his soybean crop just north of Cape Charles on
> Virginia's
> Eastern Shore and the wind off the Chesapeake Bay blew dust and
> grasshoppers
> across the drilling site, it was hard to imagine the scale of what
> geologists
> believe happened there.
>
> "This is so big that we can't really picture it," said David Powars, a
> U.S.
> Geological Survey geologist, who said he first suspected the presence of
> an
> impact crater in the 1980s. "You could take the whole nuclear arsenal in
> its
> heyday: Russia, China, U.S. ... That's a firecracker compared to what this
> explosion would be."
>
> The men and women of the small but intense crater community who gather at
> the
> spot attempt to picture it every day. "I dream this all the time," Powars
> said.
> "People say, 'Did you sleep?' I say, 'I worked all night dreaming it.' I
> try,
> but I'll be honest: I can't imagine the event."
>
> Their work is the culmination of a five-year project in which the USGS has
> drilled six holes probing the crater's landscape. This hole will be the
> program's deepest, and the last, officials say.
>
> Since the formal announcement in 1995 of what is now called the Chesapeake
> Bay
> Impact Crater, studies have detailed its dimensions and outline, experts
> say.
> Last year, scientists for the first time found rock that had been melted
> by the
> impact and fossils of microorganisms that had been smashed in the event.
>
> There are scores of known impact sites around the world and millions more
> on
> planets and moons across the solar system. The one near Norfolk is Earth's
> seventh-largest site and the biggest in the United States.
>
> On Earth, such impacts can dramatically alter the landscape in seconds,
> geologists say. And some scientists believe that understanding the moment
> of
> impact, "the soul ... the spirit" of the collision, as one said, might be
> a key
> to understanding the formation of the solar system.
>
> "If you think about how the Earth was formed," geologist Henning Dypvik of
> the
> University of Oslo said Wednesday at the drilling site, "the Earth was
> formed by
> a meteorite that came from here, an asteroid that came from there and (a)
> comet
> that came from here."
>
> He moved his hands as if making a snowball. "This is the base process for
> the
> formation of the Earth and the universe," he said. "By studying (impacts),
> by
> understanding the mechanisms, then we can know much more about the Earth
> and the
> formation of the planetary system."
>
> And then there is the question: What if such an object struck today? Even
> one a
> fraction of the size of the Chesapeake's would cause a disaster, said
> Powars,
> one of the people who discovered the crater. An impact by something a half
> a
> mile in size, and "the East Coast is in trouble," he said. "Lights out."
>
> Impact science is fairly young, the geologists said. As recently as 20
> years
> ago, the study of Earth impacts by "rocks ... from heaven," as Dypvik put
> it,
> was considered crazy. The Earth's visible craters were thought to be
> remnants of
> volcanoes, he said.
>
> Gradually, the scientific community realized that the Earth, like other
> planets,
> had been peppered over billions of years by renegade objects streaking
> through
> space. There are now more than 170 impact structures identified around the
> globe, more than 50 in North America.
>
> The Earth's biggest, 186 miles across, is at Vredefort, South Africa.
>
> The third-largest, the 100-mile-wide Chicxulub Crater on Mexico's Yucatan
> Peninsula, is believed to be the result of an impact 65 million years ago
> that
> blew so much debris into the atmosphere that it darkened the Earth for
> months
> and led to the extinction of the dinosaurs.
>
> Geologists don't believe that kind of thing happened after the Chesapeake
> impact. It "would have killed off the local population" for hundreds of
> miles up
> and down the coast, said Jean Self-Trail, a Geological Survey
> micropaleontologist. "But we don't really have any evidence that there was
> a
> massive die-off."
>
> Small impacts happen almost all the time on Earth, said Jens Ormo, a
> Swedish
> crater expert working at Chesapeake site for the Spanish space agency. The
> big,
> so-called hypervelocity impacts are quite rare. He said one of the most
> recent
> occurred about 50,000 years ago and formed Arizona's Barringer Meteorite
> Crater.
>
> The Chesapeake crater is the result of what geologists say was a marine
> impact.
> The object struck in several hundred feet of water far off the coastline,
> which
> was west of Richmond during the period of high global sea levels.
>
> "It basically vaporized billions of tons of seawater," Powars said.
> "Billions of
> tons! And that's not exaggerating."
>
>
>
> Alan
>
> "A society whose citizens refuse to see and investigate the
> facts, who refuse to believe that their government and their
> media will routinely lie to them and fabricate a reality
> contrary to verifiable facts, is a society that chooses and
> deserves the Police State Dictatorship it's going to get."
> - Ian Williams Goddard
>
> Nemesis Peace Centre
>
> http://www.veloceraptor.free-online.co.uk/protector.html
>
> Abuse of Women and Children
>
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>
> Nemesis News
>
> http://lordcerneabbas.blogspot.com/
>
> Absolute Anarchy
>
> http://lordcerneabbastoo.blogspot.com/
>
>
.
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