[meteorite-list] Charity Shoal Crater, an Exhumed Middle Ordovician Impact Crater

[Paul H.]

Holcombe, T. L., S. Youngblut, and N. Slowey, 2013,
Geological structure of Charity Shoal crater, Lake 
Ontario, revealed by multi beam bathymetry. Geo-Marine 
Letters. col. 33, no. 4, pp 245-252
http://link.springer.com/article/10.1007%2Fs00367-013-0322-6
http://adsabs.harvard.edu/abs/2013GML....33..245H

They argue that the Charity Shoal Crater in Lake
Ontario formed as the result of an extraterrestrial 
impact event in a shallow marine environment during 
the Middle Ordovician. After the impact, it  was 
eventually buried by post-impact marine 
sedimentation, which covered it with fossiliferous
marine carbonate strata. Much later, they argue,
it was exhumed by Pleistocene glacial erosion.

Other publications are:

Holcombe, T. L., J. S. Warren, D. F. Reid, W. T. 
Virden, and D. L. Divins, 2001, Small Rimmed Depression 
in Lake Ontario: An Impact Crater? Journal of Great 
Lakes Research. vol. 27, no. 4, pp. 510-517
PDF file at http://www.glerl.noaa.gov/pubs/fulltext/2001/20010012.pdf
abstract at https://www.sciencedirect.com/science/journal/03801330/27/4

Phillip, S. A., 2013, High-resolution lake-based 
magnetic mapping and modelling of basement structures, 
with examples from Küçükçekmece Lagoon, Turkey and 
Charity Shoal, Lake Ontario. unpublished MS thesis, 
School of Geography and Earth Sciences, McMaster 
University, Hamilton, Ontario. 113 pp.
https://macsphere.mcmaster.ca/handle/11375/13532

Bathymetric map of Charity Crater area.

Great Lakes Data Rescue Project - Lake Ontario Bathymetry
https://www.ngdc.noaa.gov/mgg/greatlakes/lakeontario_cdrom/html/area12.htm
https://www.ngdc.noaa.gov/mgg/greatlakes/lakeontario_cdrom/images/a12_lg.jpg

Yours,

Paul H.