Re: Big Craters

[Gautam Majumdar <gautam@majumdar.demon.co.uk>]

Jerry D. Harris <LOKICORP@compuserve.com> wrote
>
>NAME OF CRATER:  Morokweng
>LOCATION:  southern Africa
>AGE:  at or very near Jurassic-Cretaceous boundary (with which no mass
>extinctions are associated)
>CRITERIA ON WHICH IT IS BASED:  mostly seismic and gravity anomaly (crater
>is subsurface), but also petrologic and geochemical
>SIZE OF CRATER:  340 km (~154 miles) diameter
>REFERENCES:
>
>Koeberl, C., Armstrong, R.A., and Reimold, W.U.  1997.  Morokweng, South
>Africa:  a large impact structure of Jurassic-Cretaceous boundary age. 
>_Geology_ 25(8):  731-734.
>
>Corner, B., Reimold, W.U., Brandt, D., and Koeberl, C.  1997.  Morokweng
>impact structure, Northwest Province, South Africa:  geophysical imaging
>and shock petrographic studies.  _Earth and _Planetary Science Letters_
>146:  351-364.
>
Size of this crater could be much smaller - estimates vary from 70 to 340 km.

McKinnon W B, Extreme Cratering, Science 1997; 276:1346-48

Gautam Majumdar                 gautam@majumdar.demon.co.uk