[meteorite-list] Hints of Cosmic Crash at Serpent Mound in Ohio

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Apr 12 14:53:41 2005
Message-ID: <200504121834.j3CIY2t26512_at_zagami.jpl.nasa.gov>

http://www.cleveland.com/news/plaindealer/index.ssf?/base/news/1113298400177153.xml
 
Hints of cosmic crash at Serpent Mound
Bill Sloat
Plain Dealer (Ohio)
April 12, 2005

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 02:34:01 PM PDT