The Kaali Craters

Island of Saaremaa, Estonia

Panoramic photo composite of the main crater (click on the image for higher resolution)

This weekend I have been reading Mark Wilson’s posts about student fieldwork on the Island of Saaremaa. This reminded me that I have long been planning to post these photos, which have been sitting around gathering digital dust for the past three years.

The Kaali craters are shocking. They are some of the freshest meteorite impact structures that you could possibly experience, short of finding yourself in in the path of one of those “RV-sized” chunks that will pass the Earth tomorrow. These craters are a bit older than tomorrow, but geologically speaking they happened just yesterday. Age estimates seem to vary, from about 3000-7500 years old; the craters have seen little erosion and exhibit crisp rims of tilted dolostone.

Trees grip the stone of the crater rim

They were formed by the impact of quite a large iron meteorite, which at time of impact is estimated to have weighed 20-80 tonnes!  There are actually nine craters within one square kilometre. These photos are of the main crater, about 100 metres across, which contains Kaali Lake.

As is appropriate for the pleasant, civilized Island of Saaremaa, the Kaali craters have become a modest and polite rural tourist attraction. Unlike the Niagara Fallses of this world, they do not trowel on the pancake makeup and oversell their wares. But then again, they have no need. They are the real deal: fresh structures that startle you with the immediacy of a catastrophic natural phenomenon.

The surface of Kaali Lake

© Graham Young, 2011