Tunnunik - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 72° 27' 16" N; 113° 49' 49" W
Notes
  1. NW Victoria Island.
Country Canada
Region Northwest Territories
Date Confirmed 2013
Notes
  1. Confirmed by the discovery of widespread shatter cones (Dewing et al., 2013).
Buried? No
Notes
  1. Structure well exposed in polar desert.
Drilled? No
Target Type Sedimentary
Notes
  1. Lower Palaeozoic carbonates. Precambrian to Silurian-aged dolostone and limestone exposed within the structure (Dewing et al., 2013).
Sub-Type Carbonate
Apparent Crater Diameter (km) 28 km
Age (Ma) 430 - 450
Notes :
  1. Palaeomagnetic dating of target rocks and lithic impact breccia dykes indicate an impact age between 430 and 450 Ma during the late Ordovician or Silurian (Lepaulard et al., 2019). Additional age constraints: Youngest rocks affected by impact are Late Ordovician (approximately 450 Ma); impact is younger than dolomitization of Ordovician limestones possibly in the Late Ordovician (approximately 360 Ma) but older than the Early Cretaceous regional faults that cross-cut the impact structure (Dewing et al., 2013).

Method :
  1. Palaeomagnetism
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
6
  1. No crater-fill remains, crater floor has been removed, ejecta eroded, and only isolated breccia dykes remain. Estimated that up to ~1.5 km of erosion has occurred since the impact event (Quesnel et al., 2020).
Final Rim Diameter
Unknown
Apparent Rim Diameter
28 km
  1. Based on inward-dipping listric faults and detailed shatter cone mapping the apparent diameter is 28 km (Osinski et al., 2013) (Osinski and Ferriere, 2016).
Rim Reliability Index
1
  1. Shatter cones are found within an ~10x12 km area, corresponding to the central uplift (Osinski and Ferriere, 2016).
Crater Morphology
Complex
Central Uplift Diameter
10-12km
Central Uplift Height
Unknown
Uplift Reliability Index
2
Structural Uplift
1 km
Thickness of Seds
Target Age
Palaeozoic
Marine
No
Impactor Type
Other Shock Metamorphism
No
Shatter Cones
Yes
  1. (Dewing et al., 2013) report abundant shatter cones within all units in the central area, becoming less abundant and more isolated towards the margins. In the thicker bedded dolomites of the Victoria Island and Thumb Mountain formations, they reach approximately 50 cm in vertical extent (Figs. 7A, 7B and 7D), while those in thinner bedded strata are several to approximately 20 cm depending on bedding thickness (Figs. 6C, 7C, 7D, and 7F; Dewing et al., 2013). (Dewing et al., 2013) reports both upward and downward facing cone apices See Fig. 1B (Osinski and Ferriere, 2016) for shatter cone spatial distribution. Shatter cones are distributed over an area of 10.1 km to 12.0 km and in many instances, the nonoccurence of shatter cones were traced to distances of <100 m and in outcrops of the same lithology (Osinski and Ferriere, 2016). The nonoccurence of shatter cones occurs at ~ 1 to 2 km inside the outer edge of uplifted strata, and there are no shatter cones in the crater rim region (Osinski and Ferriere, 2016). Shatter cone apices pointed in various directions, often in completely opposite directions (Osinski and Ferriere, 2016). Complete shatter cones observed and shatter cones with very curved nonplanar surfaces (Fig. 3D; Osinski and Ferriere, 2016). Size of cones decreases with increasing distance from the centre, as well as the morphological definition (Fig. 1A, 1C, and 1D; Osinski and Ferriere, 2016).
Planar Fractures
No
Planar Deformation Features
Yes
  1. PDF in quartz (Pickersgill and Osinski, 2013).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
  1. Crater-fill impactites have been eroded. Monomict, polymict, melt-bearing (silicate glass and carbonate melt) and lithic breccias are reported by (Newman, 2020).
Proximal Ejecta
Distal Ejecta
Dykes
LB, M, MB
Volume of Melt
Depth of Melting

References

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K Dewing, B R Pratt, T Hadlari, T Brent, J Bédard, R H Rainbird (2013) Newly identified "Tunnunik" impact structure, Prince Albert Peninsula, northwestern Victoria Island, Arctic Canada, Meteoritics and Planetary Science 48(2), p. 211-223, doi:10.1111/maps.12052

A E Pickersgill, G R Osinski (2013) Planar deformation features in quartz at the newly discovered Prince Albert impact structure, Northwest Territories, Canada, 44th Lunar and Planetary Science Conference, p. Abstract 2602, Lunar and Planetary Science Conference, Houston, TX

G R Osinski, R Francis, J Hansen, C L Marion, A E Pickersgill, L L Tornabene (2013) Structural mapping of the Tunnunik impact structure, NWT, Canada: Insights into central uplift formation, Large Meteorite Impacts and Planetary Evolution V, p. Abstract 3060

G R Osinski, S Abou-Aly, R Francis, J Hansen, C L Marion, A E Pickersgill, L L Tornabene (2013) The Prince Albert Structure, Northwest Territories, Canada: A new 28-km diameter complex impact structure, 44th Lunar and Planetary Science Conference, p. Abstract 2099, Lunar and Planetary Science Conference, Houston, TX

C L Marion, G R Osinski, R L Linnen (2013) Characterization of hydrothermal mineralization at the Prince Albert impact structure, Victoria Island, Canada, 44th Lunar and Planetary Science Conference, p. Abstract 1635, pdf

J D Newman, G R Osinski (2016) Geological mapping of the Tunnunik impact structure, Victoria Island, Canadian High Arctic, 47th Lunar and Planetary Science Conference, p. Abstract 1591, Lunar and Planetary Science Conference, Houston, TX

G R Osinski, L Ferrière (2016) Shatter cones: (Mis)understood?, Science Advances 2(e1600616), p. 1-9, American Association for the Advancement of Science, doi:10.1126/sciadv.1600616

W Zylberman (2017) Geophysical study of complex meteorite impact structures, p. 254, url

B H Choe, L L Tornabene, G R Osinski, J D Newman (2018) Remote predictive mapping of the Tunnunik impact structure in the Canadian Arctic using multispectral and polarimetric SAR data fusion, Canadian Journal of Remote Sensing 44(5), p. 513-531, Taylor and Francis Inc., doi:10.1080/07038992.2018.1544846

C Lepaulard, J Gattacceca, N I Swanson-Hysell, Y Quesnel, F Demory, G R Osinski (2019) A Paleozoic age for the Tunnunik impact structure, Meteoritics & Planetary Science 54(4), p. 740-751, University of Arkansas, doi:10.1111/maps.13239

Y Quesnel, W Zylberman, P Rochette, M Uehara, J Gattacceca, G R Osinski, P Dussouillez, C Lepaulard, C Champollion (2020) Geophysical signature of the Tunnunik impact structure, Northwest Territories, Canada, Meteoritics & Planetary Science 55(3), p. 480-495, University of Arkansas, doi:10.1111/maps.13447