Petrographic analysis revealed planar deformation features broadly supportive of shock metamorphism (Spooner et al.
Thin sections were prepared from the samples and examined visually for evidence of shock metamorphism using a Nikon Optiophot-Pol microscope.
Bedrock samples from the vicinity of the North structure contain planar deformation and other petrographic features broadly consistent with those observed in samples from the Bloody Creek structure but not diagnostic of shock metamorphism.
By contrast, a decisive argument for a meteorite impact is provided by the shock metamorphism observed on examples of ejected quartz minerals (Ernstson et al.
Shock metamorphism of quartz in nature and experiment: I.
It is a complex crater by type with evidence of shock metamorphism (Dietz 1960; Cohen and others 1961; Carlton and others 1998; Milam and others, 2011) required for impact crater identification (French 1998).
Discovery of microscopic evidence for shock metamorphism at the Serpent Mound structure, south-central Ohio: confirmation of an origin by impact.
The impact event itself is chiefly documented by the abundant occurrence of shock metamorphism
Shock metamorphism of rock present at the time of impact provides a more definitive means of constraining the age of an impact event.
Only rock present at the time of impact will contain these definitive macro-scale indicators of shock metamorphism.
This mineral fabric is related to shock metamorphism and supports an impact origin for the structure.
Carlton RW, Koeberl C, Baranoski MT, Schumacher GA 1998 Discovery of microscopic evidence for shock metamorphism at the Serpent Mound structure, south central Ohio: confirmation of an origin by impact.