Spider
Key facts
- Country
- Australia
- Diameter
- 13 km
- Age
- more than about 570 million years
- Location
- 16.73° S, 126.08° E
A striking pattern of ridges radiating from a central uplift, like the legs of a spider, in the remote Kimberley region of Western Australia.
Spider is an eroded impact structure about 13 km across in the remote Kimberley region of Western Australia. It is named after its striking appearance from the air: ridges of sandstone radiate outwards from a central area like the legs of a spider.
What can be seen. The central uplift is surrounded by ridges of hard sandstone that were pushed and folded inwards towards the centre during the impact. Erosion has picked out these ridges, making the pattern visible from space.
What it hit. The impactor struck Proterozoic sandstones and siltstones of the Kimberley Basin.
Proof of impact. Geologists found shatter cones, cone-shaped fractures produced by shock, and quartz grains with planar deformation features, which confirmed an impact.
Age. The age is poorly known. The structure is older than about 570 million years, based on the age of rocks that cover parts of the region.
Why it matters. Spider's unusual radial pattern suggests that the impactor may have struck at a low angle. Studies of the structure help scientists understand how oblique impacts shape craters. The impactor is unknown.
Visiting. The area is remote. Much of the Kimberley is Aboriginal land or pastoral lease; ask permission before entering.
Did you know?
Spider is named after ridges that radiate from its centre like a spider's legs.
Its shape suggests the impactor came in at a low angle.
The pattern is visible from space.