astrobleme
American Heritage Dictionary:
Top
as·tro·bleme
(ăs'trə-blĕm', -blēm') 
n.
A scar on the earth's surface left from the impact of a meteorite.
n.
A scar on the earth's surface left from the impact of a meteorite.
[ASTRO- + Greek blēma, missile, wound (from ballein, to throw).]
Wiley Book of Astronomy:
Top
astrobleme
A highly eroded meteorite crater on Earth, of which about 150 are known. The largest are the 200-km-wide Sudbury Crater in Ontario, Canada, and the 180-km-wide Chicxulub Basin in Mexico. While some astroblemes are almost 2 billion years old, about 60% were formed within the past 200 million years. See also Earth impact craters.
Columbia Encyclopedia:
Top
astrobleme
astrobleme (ăs'trōblēm'), large, circular structure ranging from c.1/2 mi to 40 mi (.8-64 km) in diameter. Astroblemes are found at numerous places on the earth's surface, e.g., Meteor, or Barringer, Crater in Arizona, Brent Crater in Ontario, and Vredefort Ring in South Africa. The presence of meteor fragments, strange conical fracture patterns (called shatter cones), and coesite (a superdense, high-pressure form of quartz) in the rocks at astroblemes suggest an impact, rather than volcanic, origin to these circular structures.
Post a question - any question - to the WikiAnswers community:
Copyrights:
American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
Read more
Wiley Book of Astronomy
Copyright © 2004 by Wiley-Blackwell. Wiley and the Wiley logo are registered trademarks of John Wiley & Sons, Inc. and/or its affiliates in the United States and other countries. Used here by license. Read more
