[meteorite-list] Possible Ohio crater

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Tue Apr 12 11:16:14 2005
Message-ID: <uspn51pjdoup75nsphkuf1b96ro96cjoko_at_4ax.com>

http://www.cleveland.com/news/plaindealer/index.ssf?/base/news/1113298400177153.xml


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Hints of cosmic crash at Serpent Mound
Tuesday, April 12, 2005
Bill Sloat
Plain Dealer Reporter
Cincinnati

-- Sifting through rocks snagged from twin boreholes punched deep into the planet's crust,
scientists have detected an unearthly substance hidden for eons in Ohio's basement.

 
And its presence 1,412 feet beneath the forests and farmlands near Serpent Mound in south-central
Ohio -- already on par with Britain's Stonehenge and Egypt's pyramids as one of Earth's most
mysterious manmade structures -- adds to a puzzle shrouded in legend and lore for centuries.

When scientists peered into the geo-strata that emerged from beneath the mound, they were confronted
with pure, weird data. Under their microscope, they saw quartz crystals with flaws like those found
at nuclear test sites and in moon rocks brought back by astronauts.

It pointed toward a massive energy burst that left behind telltale traces of a cosmic crash.

Now, those findings are rattling through the world of geology, shaking up long-held conceptions and
misconceptions about Ohio's distant past.

"I think we can say with authority today that this is an impact from a meteorite," said Mark T.
Baranoski, a state geologist. "It affected the region in a spectacular way."

Rock samples from beneath the mound contain significantly higher than normal concentrations of
iridium, an extremely rare metal. Because it is so heavy, iridium seldom shows up anywhere but near
the planet's molten core.

At Serpent Mound, the levels measured were 10 times beyond what is usually present in the Earth's
crust.

Occasionally, volcanoes bring it up in lava. But there are no lava fields in Ohio. So the questions
started. Where did the iridium-rich rocks come from?

While iridium is scarce on Earth, the silver-gray metal is common in asteroids and comets.

In other words, it often is a strong sign that the sky has fallen.

Geologists, including researchers from the Ohio Department of Natural Resources, describe the recent
discovery as powerful new evidence that Serpent Mound sits upon a slightly oblong crater created
when a massive extraterrestrial object slammed into Earth.

They have reported that the heavy metal find is "good evidence for an impact origin" and that dark,
stony material recovered from the deepest borehole has a "significant enrichment" that must have
come from outer space.

Iridium is already at the center of another scientific mind-bender - the disappearance of the
dinosaurs.

In a widely accepted doomsday scenario, an asteroid the size of Manhattan plunged into the sea off
Mexico's Yucatan Peninsula 65 million years ago. The explosion devastated the planet and unleashed a
worldwide wipeout that caused 70 percent of all living things to die.

Scientists say they have found an iridium line in the Earth's crust that few species crossed. Under
the great extinction theory, the iridium showered down in debris after the asteroid struck.

Not all scientists accept the doomsday scenario, but many say it does seem to explain why the
dinosaurs died off.

A similar event - although without those dramatic global effects - looks to have taken place in
Ohio.

The crater touches portions of Adams, Pike and Highland counties, about 200 miles southwest of
Cleveland in the state's rolling Appalachian countryside.

The mound, built about 1,000 years ago, straddles land near the crater's southwest edge and may have
had a religious function, although nobody knows for sure what philosophy and beliefs shaped its
origin.

Of course, that hasn't stopped people from speculating about Serpent Mound's builders and what they
were up to. Some say they were mystics and priests. Others say magicians and soothsayers. Still
others see them as prophets.

There are those who claim that the builders were shamans who practiced human sacrifice, while some
believe that they were ancient astronomers who were the intellectual caste of woodland America.

Fact is, nobody can say. The mound builders left no written records.

Erosion and Ice Age glaciers have erased most of the crater from the surface.

But underground it's a far different story, and the boreholes exposed the geologic record.

Fine grains of sand taken from 1,439 feet down appear deformed when viewed under a microscope. There
even seem to be particles of soot left from scorched limestone, although researchers say additional
work is needed before the strange black material is positively identified.

Still, everything seems to point to a cosmic jolt. While some aren't convinced, they agree the
evidence is piling up.

Mike Hansen, a retired state geologist who runs an earthquake warning system and teaches at Ohio
State University, said there is no doubt that the Serpent Mound area was disturbed by some unknown
force. But Hansen thinks the stresses were triggered by natural shifts in the Earth's crust.

Around the time the rocks were deformed, Hansen said, Africa was pushing into North America and the
Appalachian Mountains range was thrusting up higher than today's Himalayas. He said a major tectonic
event like that could have created the underground chaos at Serpent Mound.

Still, Hansen concedes that the meteorite hypothesis is gaining adherents among geologists.

The object, if it did strike Ohio, would have been gigantic. Maybe up to three times larger than
Cleveland Browns Stadium. Traveling up to 45,000 mph, it would have been moving much faster than a
speeding bullet.

The searing heat, blast and shockwaves from such a crash would have instantly carved a
1,000-foot-deep hole and crushed rocks miles below the five-mile-across crater.

That is exactly what samples from the two boreholes show. Researchers have spotted microscopic
cracks in quartz crystals far beneath the surface and horsetail-shaped fractures called "shatter
cones" in geological formations from the ground on down. The cracked crystals have patterns
resembling those appearing after U.S. nuclear weapons tests in Nevada.

Other than iridium, there is no trace of an asteroid or comet.

It would probably have vaporized when it hit 256 million years ago.

"I don't think we'll ever find it," Baranoski said. "It would have gone up in smoke. If anything was
left near the surface, it would have been eroded away."

Doyle Watts, a geophysicist at Dayton's Wright State University who worked on the international team
that studied the core samples, said the impact theory explains why so much of the terrain around
Serpent Mound appears jumbled.

Some rock formations rise 1,000 feet above the ground. Others look like they have slid straight
down.

Those oddities were first noticed not long after Europeans settled Ohio.

John Locke, a geologist who explored the area in the 1830s, thought he had found a "sunken mountain"
and reported that "a region of no small extent had sunk down several hundred feet, producing faults,
dislocations and upturnings of the layers of the rocks."

Even more weird was the 1,348-foot-long Serpent Mound, which looked like an undulating snake atop a
plateau overlooking Brush Creek.

Watts said he believes that the Indians saw the strange features in the land and were moved to build
the mound, perhaps as a sacred monument. He said the Indians were deeply attuned to the natural
world.

"It just begs the questions: Why would Native Americans lug tons of soil and shape it into a
slithering serpent? Why would they choose to do so on the scar of an ancient impact when they had
all of Ohio and the Midwest?" Watts said.

"My guess is that they could have noticed something strange about the rocks. It has to be more than
coincidence."
Received on Tue 12 Apr 2005 11:23:03 AM PDT