[meteorite-list] New Geology About Non-Impact Circular Features

[Paul H.]

An interesting paper by Dr. B. J. Tewksbury an others
has been published online in Geology. It talks about a
well exposed system of polygonal faults that are 
exposed in outcropping chalks in the Western Desert 
of Egypt at Latitude 27.289982 N, Longitude 28.491490 E.
There polygonal fault systems form numerous circular 
structures displaying shallow inward dips. Although they 
would not confuse expert interpreters of aerial imagery,
amateur fans of Google Earth might confuse them with
an impact crater field. They do show that ther are a
variety of non-impact processes that can create circular 
structures.

The paper is:

Tewksbury, B. J., H. P. Hogan, S. A. Kattenhorn,
C. J. Mehrtens, and E. A. Tarabees, 2014, Polygonal 
faults in chalk: Insights from extensive exposures 
of the Khoman Formation, Western Desert, Egypt.
Geology. First published online April 15, 2014, doi: 10.1130/G35362.1
http://geology.gsapubs.org/content/early/2014/04/14/G35362.1

Pictures of these circular features can also be found in:

Geological Society of America Data Deposity no 
2014165 (Tewksbury et al. Polygonal faults in chalk:
insights from extensive exposures of the Khoman 
Formation, Western Desert, Egypt) PDF file at:
ftp://rock.geosociety.org/pub/reposit/2014/2014165.pdf

Additional links about paper:

Tewksbury Publishes Article in Geology
by Vige Barrie, Hamilton, April 28, 2014
http://www.hamilton.edu/news/story/tewksbury-publishes-article-in-geology
sit/2014/2014165.pd 

Yours,

Paul H.