Sudbury Structure: An Analog Site for Past Lunar Geologists and Future Planetary Scientists

The Sudbury Structure is an elliptical basin roughly 60 by 30 kilometers, about 300 kilometers north of Toronto. It is a major mining district for nickel, copper, and platinum group elements, and thought for many decades to be an igneous structure. However, it was proposed by R.S. Dietz in 1964 on the basis of predicted shatter cone occurrences that the structure was an impact crater, a theory shortly after confirmed by B.M. French on the basis of shock features in the breccias. Recent research by French and others has called attention to the importance of carbon in the Onaping Formation, with possible biological implications.

The Sudbury Structure was used as a training site for the Apollo 16 astronauts in 1971, and enabled them after landing on the Moon to instantly recognize the Cayley Formation as impact breccia rather than volcanic rock. We suggest that the Sudbury Structure be considered as a training site for planetary field scientists. We recommend this site to educators who wish to expose students to terrestrial examples of processes and rocks probably analogous to features seen on planetary remote sensing data. The geology is now thoroughly mapped and extremely well-exposed, and the entire Structure easily accessible by road. The greater Sudbury area has several universities and an office of the Ontario Geological Survey, and is served by scheduled air lines. It therefore is recommended as an analog site for training future planetary geology students.