Where have all the craters gone?

May 28, 2014 by Kea Giles
Ouarkziz Impact Crater. Credit: NASA

Impact craters reveal one of the most spectacular geologic process known to man. During the past 3.5 billion years, it is estimated that more than 80 bodies, larger than the dinosaur-killing asteroid that struck the Yucatan Peninsula 66 million years ago, have bombarded Earth. However, tectonic processes, weathering, and burial quickly obscure or destroy craters. For example, if Earth weren't so dynamic, its surface would be heavily cratered like the Moon or Mercury.

Work by B.C. Johnson and T.J. Bowling predicts that only about four of the craters produced by these impacts could persist until today, and geologists have already found three such craters (larger than 170 km in diameter). Their study, published online for Geology on 22 May 2014, indicates that craters on Earth cannot be used to understand Earth's bombardment history.

Johnson and Bowling write, however, that layers of blasted out early in the impact process may act as better records of impacts—even after the active Earth has destroyed the source craters. The authors suggest that searches for these impact ejecta layers will be more fruitful for determining how many times Earth was hit by big asteroids than searches for large craters.

Explore further: Image: A peppering of craters at the Moon's south pole

More information: B.C. Johnson and T.J. Bowling. Where have all the craters gone? "Earth's bombardment history and the expected terrestrial cratering record." Geology, G35754.1, first published on May 22, 2014, DOI: 10.1130/G35754.1

add to favorites email to friend print save as pdf

Related Stories

Image: A peppering of craters at the Moon's south pole

May 26, 2014

(Phys.org) —The dark and shadowed regions of the Moon fascinate astronomers and Pink Floyd fans alike. Our Moon's rotation axis has a tilt of 1.5º, meaning that some parts of its polar regions never see ...

Moon may harbour alien minerals, study says

May 26, 2013

Minerals found in craters on the Moon may be remnants of asteroids that slammed into it and not, as long believed, the satellite's innards exposed by such impacts, a study said Sunday.

What craters on the Moon teach us about Earth

Jan 10, 2013

Some questions about our own planet are best answered by looking someplace else entirely… in the case of impact craters and when, how and how often they were formed, that someplace can be found shining ...

Recommended for you

First Swedish hard-rock diamonds discovered

2 minutes ago

An Uppsala-led research group has presented the first verified discovery of diamonds in Swedish bedrock. The diamonds are small, but provide important clues to the geological evolution of rocks.

Harnessing crowds to analyze clouds

22 minutes ago

(Phys.org) —When it comes to analyzing hurricanes and other tropical cyclones, lack of data isn't the problem. Scientists have 30 years' worth of satellite images of these massive storms. However, what ...

NASA image: Smoke and haze over China

22 hours ago

Smoke and haze hang over a large portion of eastern China in this image captured by the Aqua satellite on October 29, 2014. China uses the method of "slash and burn" agriculture to rid their fields of leftover ...

User comments : 4

Adjust slider to filter visible comments by rank

Display comments: newest first

Nik_2213
5 / 5 (1) May 28, 2014
Linky says 'Free to you' for the article but, when you try to down-load the PDF, it states, 'This item requires a subscription to Geology.'

Sad...
hemitite
5 / 5 (4) May 28, 2014
Where have all the craters gone?
Long time passing;
Where have all the craters gone?
Long time ago;
Where have all the craters gone?
Erosion got most everyone;
Where was ejecta thrown?
Where was eje-ecta thrown?
avblanch
5 / 5 (4) May 28, 2014
@hemitite - Although he wouldn't sign in himself to respond, my husband (B.C. Johnson) throughly enjoyed finding your poem in the comments. It was a pleasant surprise and will no doubt be repeated in lab conversations.
Kalopin
1 / 5 (1) Jul 27, 2014
Dear B.C. Johnson and T.J.Bowling,

The Mediterranean Sea, Hudson bay and Mississippi embayment are three of the world's largest astroblemes...
http://able2know....224693-1
science may have some catching up to do? ;-]

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.