Evidence supporting an impact origin includes the geological structure of the crater, and the discovery of shocked quartz.

As of 2011 there were still no reports of definite evidence, such as shatter cones or shocked quartz.

The presence of shocked quartz proves that these craters were formed by an impact: a volcano would not generate the pressure required.

In 2008, it was announced that shocked quartz was discovered.

Now they had more than fossils and shocked quartz to use as a peek into the past.

The impactite featured a form of shocked quartz known as "coesite", and is thus clearly the product of an impact event.

Grains of shocked quartz have been found in deposits of that age worldwide.

It, too, seems to have been a source of shocked quartz.

Evidence for the impact origin of the crater includes shocked quartz, a gravity anomaly, and tektites in surrounding areas.

This interpretation is supported by the presence of shocked quartz and biotite.