Crawford
Key facts
- Country
- Australia
- Diameter
- 8.5 km
- Age
- more than about 35 million years
- Location
- 34.72° S, 139.03° E
No crater shape: gently rolling farmland in the Adelaide Hills region of South Australia, where shatter cones occur in a few outcrops.
Crawford is a deeply eroded impact structure about 8.5 km across in South Australia, north-east of Adelaide. It lies only a few kilometres from another eroded structure, Flaxman.
Discovery. Geologists found shatter cones, cone-shaped fractures produced only by the shock of an impact, in outcrops of folded rock. Microscopic shock features in quartz confirmed an impact.
What it hit. The impactor struck late Precambrian and Cambrian sedimentary rocks of the Adelaide Fold Belt, which had already been folded and metamorphosed during an earlier period of mountain building.
Age. The age is poorly known. The impact happened before younger sediments were deposited over the area, so it is older than about 35 million years, but it may be much older.
Why it matters. Crawford and Flaxman are two of the few impact structures close to a large Australian city. Erosion has removed all trace of their crater shapes, but the shocked rocks remain. The impactor is unknown.
Visiting. The area is farmland. Ask landowners' permission before looking for shatter cones.
Did you know?
Crawford lies only a few kilometres from another impact structure, Flaxman.
Shatter cones revealed the impact.
No crater shape survives.