| Carswell impact structure | |
|---|---|
 In the northern part the rim is visible as a series of low hills, in the southern part it is indicated by the course of Douglas River. Carswell Lake (in the upper right) cuts into the structure. | |
| Impact crater/structure | |
| Diameter | 39 kilometres (24 mi) |
| Age | 115 ± 10 million years (Lower Cretaceous) |
| Exposed | Yes |
| Drilled | Yes |
| Location | |
| Coordinates | 58°26′26″N 109°30′24″W / 58.44056°N 109.50667°W |
| Country | Canada |
| Province | Saskatchewan |
  Carswell impact structure Location of Carswell impact structure in Saskatchewan | |
| Topo map | NTS 74K5 Cluff Lake, 74K6 Jolley Lake |
| Access | Saskatchewan Highway 955 |
Carswell is an impact structure within the Athabasca Basin of the Canadian Shield in northern Saskatchewan, Canada.[1] It is 39 kilometres (24 mi) in diameter and the age is estimated to be 115 ± 10 million years (Lower Cretaceous). The impact structure is exposed at the surface.
The central peak complex of faulted metamorphic rocks displays shatter cones, planar deformation features, pseudotachylyte veins, and impact melts and breccias. There is also evidence of planar deformation features in quartz grains far to the south of the outer ring of present-day hills, which suggests the ring of hills are not the rim of the original crater but a peak ring within a much larger structure. The Carswell Formation, composed of algal limestone, may have formed on seamounts elevated to near the surface as part of the peak ring.[2]
- ^ "Carswell". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2008-12-30.
- ^ a b Genest, S.; Robert, F.; Duhamel, I. (2010). "The Carswell impact event, Saskatchewan, Canada: Evidence for a pre-Athabasca multiring basin?". In Reimold, W.U.; Gibson, R.L. (eds.). Large Meteorite Impacts and Planetary Evolution IV. Geological Society of America Special Paper. Vol. 465. pp. 543–570. doi:10.1130/2010.2465(26). ISBN 9780813724652.