Strangways
Key facts
- Country
- Australia
- Diameter
- 25 km
- Age
- about 646 ± 42 million years
- Location
- 15.20° S, 133.58° E
A broad area of rocky hills in the remote Northern Territory, with a central core of granite and gneiss surrounded by sandstone ridges.
Strangways is an eroded impact structure about 25 km across in the remote north of the Northern Territory, Australia, south-east of Katherine.
What it hit. The impactor struck Proterozoic sandstones and other sedimentary rocks lying over older crystalline basement. The rebound of the crater floor lifted the basement to the surface in the centre, where granite and gneiss are now exposed, surrounded by rings of tilted sandstone.
Proof of impact. Geologists found shatter cones, cone-shaped fractures produced by shock, quartz with planar deformation features and impact melt rock, which confirmed an impact.
Age. Argon dating of the melt rock gives an age of about 646 million years, in the late Precambrian, with an uncertainty of about 42 million years.
Why it matters. Strangways is one of the larger and better-studied ancient impact structures in northern Australia. Its exposed central uplift shows how deep basement rocks are raised in large craters. The impactor is unknown.
Visiting. The area is remote and much of it is Aboriginal land or pastoral lease. Ask permission before entering.
Did you know?
Granite from deep below was lifted to the surface in the centre of Strangways.
It is about 646 million years old.
Rock melted by the impact survives there.