Carswell impact structure

{{Short description|Impact structure in Saskatchewan, Canada}}

{{Infobox terrestrial impact site

| name = Carswell impact structure

| other_name =

| photo = Carswell Crater - Landsat TM 42.jpg

| photo_size = 235

| photo_alt =

| photo_caption = 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.

| location =

| map = Canada Saskatchewan

| map_alt =

| map_caption = Location of Carswell impact structure in Saskatchewan

| map_size = 235

| label_position =

| coordinates = {{coord|58|26|26|N|109|30|24|W|format=dms|display=inline,title}}

| coordinates_ref =

| confidence =

| diameter = {{convert|39|km|mi|0}}

| depth =

| age = 115 ± 10 million years (Lower Cretaceous)

| exposed = Yes

| drilled = Yes

| bolide =

| topo = NTS {{Canada NTS Map Sheet|74|K|5}}, {{Canada NTS Map Sheet|74|K|6}}

| access = Saskatchewan Highway 955

| country = Canada

| state =

| province = Saskatchewan

| district =

| municipality =

}}

Carswell is an impact structure within the Athabasca Basin of the Canadian Shield in northern Saskatchewan, Canada.{{Cite Earth Impact DB | name = Carswell | accessdate = 2008-12-30 }} It is {{convert|39|km|mi|0}} in diameter and the age is estimated to be 115 ± 10 million years (Lower Cretaceous). The impact structure is exposed at the surface.

File:Carswell Crater - Landsat TM 42 structure.jpg

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.