Eagle Butte - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 49° 42' 6" N; 110° 30' 20" W
Notes
  1. SE Alberta, 3 km W of Cypress Hills Provincial Park and 50 km SE of Medicine Hat.
Country Canada
Region Alberta
Date Confirmed 1985
Notes
  1. First suggested to be an impact crater in (Dence, 1972). Confirmed based on the presence of shatter cones, PFs, and PDFs in quartz grains (Ezeji-Okoye, 1985).
Buried? Yes
Notes
  1. Under Upper Cretaceous sediments and glacial drift. Minor surface expression of the crater is detectable (Ezeji-Okoye, 1985).
Drilled? Yes
Notes
  1. Drilling, along with seismic surveys, has been used to detect the central uplift and the annular trough (Ezeji-Okoye, 1985).
Target Type Sedimentary
Notes
  1. Interior Platform, Palaeozoic carbonates and evaporites, Mesozoic and Tertiary clastic sediments (Ezeji-Okoye, 1985). Cretaceous and Phanerozoic.
Sub-Type Coal, Sandstone, Shale, Siltstone
Apparent Crater Diameter (km) 16 km
Age (Ma) <65
Notes :
  1. <65 Ma based on stratigraphic age constraints (Grieve, 2006). Uplift of Upper Cretaceous sediments is evidence that the impact event post-dates these units (Sawatzky, 1976). The structure is also buried by glacial drift.

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
5
  1. Extent of erosion unknown.
Final Rim Diameter
Unknown
Apparent Rim Diameter
16 km
  1. Structure may be 16 km (Sawatzky, 1976) (Ezeji-Okoye, 1985) (Hanova et al., 2005).
Rim Reliability Index
3
  1. Little surface expression, although the area is portrayed on geological maps as an oval, faulted region, 10 by 16 km. Circular disturbed zone defined by drainage and some small lakes (Ogilvie et al. 1984). (Hanova et al., 2005) present a seismic line that crosses the central uplift. The central uplift diameter was taken from Figure 3.
Crater Morphology
Complex
Central Uplift Diameter
4km
Central Uplift Height
Unknown
Uplift Reliability Index
4
Structural Uplift
200 m
Thickness of Seds
Target Age
Palaeozoic Mesozoic
Marine
No
Impactor Type
Other Shock Metamorphism
No
Shatter Cones
Yes
  1. Shatter cones [with an average apical angle of 73°] occur in sandy limestone (Bearpaw Formation?) in the area of the central uplift (Ezeji-Okoye, 1985). Shatter cones occur around the central part of the structure (49°41.592'N/110°30.771'W), in limestone with several fractures filled by dolomite (Field notes 2004) (Hanova et al., 2005).
Planar Fractures
Yes
  1. PF in breccia samples taken from the core of well 13-32-08-04-W4M (Ezeji-Okoye, 1985).
Planar Deformation Features
Yes
  1. PDF in quartz grains (Ezeji-Okoye, 1985).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
Proximal Ejecta
Distal Ejecta
Dykes
Volume of Melt
Depth of Melting

References

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H B Sawatzky (1976) Two probable late Cretaceous astroblemes in western Canada; Eagle Butte, Alberta and Dumas, Saskatchewan, Geophysics 41(6), p. 1261-1271, Society of Exploration Geophysicists, Tulsa, OK, url, doi:http://dx.doi.org/10.1190/1.1440678

D G W Smith, R J Lambert, J F Lerbekmo, S Ezeji-Oyoke (1990) The Eagle Butte Crater, Southeast Alberta, Program with Abstracts - Geological Association of Canada; Mineralogical Association of Canada: Joint Annual Meeting 15, p. 123, Geological Association of Canada, Waterloo, ON, url

D C Lawton, R R Stewart (1994) Geophysical signature of the Eagle Butte impact crater, Program with Abstracts - Geological Association of Canada; Mineralogical Association of Canada: Joint Annual Meeting 19, p. 62, Geological Association of Canada, Waterloo, ON, url

J Visser, D Scott (2005) An early Tertiary meteorite impact structure at Eagle Butte, Alberta, Abstracts: Annual Meeting - American Association of Petroleum Geologists 14, p. A146-A147, American Association of Petroleum Geologists and Society for Sedimentary Geology, Tulsa, OK, url

J Hanova, D C Lawton, J Visser, A R Hildebrand, Ludovic Ferrière (2005) 3D structural interpretation of the Eagle Butte impact structure, Alberta, Canada, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference 36, p. 0-unpaginated, Lunar and Planetary Science Conference, Houston, TX, url

Enrico Flamini, A Coletta, M L Battagliere, M Virelli (2019) Eagle Butte, Canada, Encyclopedic Atlas of Terrestrial Impact Craters, p. 503-505, Springer, Cham, doi:https://doi.org/10.1007/978-3-030-05451-9_139