Iowa Crater Points to Early Hit From Asteroid

Tuesday, 19 Feb 2013 01:51 PM

By Cyrus Afzali

Share:
A    A   |
   Email Us   |
   Print   |
   Forward Article  |
  Copy Shortlink
In an event that dwarfs Friday’s asteroid explosion over Russia, a Smithsonian geologist Tuesday said an asteroid as large as a city block hit northern Iowa 470 million years ago.

Bevan French, an adjunct scientist at the National Museum of Natural History, told The Washington Post the space rock left a crater nearly four miles wide beneath what is now Decorah, Iowa.

French said the asteroid’s collision with bedrock created such force that it shattered into tiny grains of minerals. The “shock quartz” was found in gravel beneath the town.

The discovery is especially unique because traces of impact craters tend to disappear with the effects of erosion and the shifting of tectonic plates. If the find is accepted by other scientists, the Decorah crater would become the 184th impact crater discovered, according to the University of Brunswick, which maintains an international database on craters.

The crater went undetected for so long, scientists say, because the vast majority of it lies underground, having been filled by an unusual shale that formed after an ancient seaway deposited sediment and sea creatures that hardened into fossils, French said.

Jean Young, an amateur geologist, was among the first to notice the shale some 12 years ago after inspecting gravel unearthed by well-drilling equipment. Young sent samples to geologist Robert McKay at the Iowa Department of Natural Resources. Young compared the sample to gravel unearthed during other well drillings and discovered a basin about 3.5 miles wide divided by the Upper Iowa River.

News of the black rock was first published in a scientific paper in 2006, in which it was called Winnesheik Shale. However, it was only after French identified the shock quartz pulled from beneath the shale that an impact from a giant asteroid seemed likely. Fossils in the shale led scientists to date the crater’s creation to about 470 million years ago, part of a period known as the Middle Ordovician that was marked by a large increase in early ocean life.

In 2004, a group of Swedish astronomers suggested that a massive collision in the asteroid belt beyond Mars about 469 million years ago resulted in fragments bombarding the Earth.

Scientists say that 20 percent of all meteorites on Earth originated during that period.


© 2014 Newsmax. All rights reserved.

Share:
   Email Us   |
   Print   |
   Forward Article  |
  Copy Shortlink
Around the Web
Join the Newsmax Community
>> Register to share your comments with the community.
>> Login if you are already a member.
blog comments powered by Disqus
 
Email:
Retype Email:
Country
Zip Code:
 
Hot Topics
Follow Newsmax
Like us
on Facebook
Follow us
on Twitter
Add us
on Google Plus
Around the Web
You May Also Like

US Wins More Guilty Pleas in First Counterfeit Apps Case

Tuesday, 15 Apr 2014 18:45 PM

The final defendants in what the U.S. government called its first prosecution of a counterfeit apps case have pleaded gu . . .

Heartbleed Fix Could Drastically Slow Internet

Tuesday, 15 Apr 2014 10:15 AM

Repairing the Heartbleed virus could cripple the Internet as the 500,000 affected websites simultaneously scramble to ch . . .

Conjoined Boys Separated at Chest to Exit Hospital

Monday, 14 Apr 2014 16:27 PM

The conditions of conjoined twins separated last summer have steadily improved, and officials say they'll be released th . . .

Newsmax, Moneynews, and Independent. American. are registered trademarks of Newsmax Media, Inc. Newsmax TV, NewsmaxWorld, NewsmaxHealth, are trademarks of Newsmax Media, Inc.

 
NEWSMAX.COM
America's News Page
©  Newsmax Media, Inc.
All Rights Reserved