Miralga - Hypervelocity Impact Crater

Alternate Names Pilbara
Coordinates 21° 3' 15" S; 119° 23' 54" E
Notes
  1. Centered at the North Pole Dome in the East Pilbara Terrane
Country Australia
Region Western Australia - Pilbara Craton
Date Confirmed 2021
Notes
  1. Confirmed based on shatter cones found during fieldwork throughout most of the thickness of the Antarctic Creek Member in the area around the North Pole Dome (Kirkland et al. 2025).
Buried? Partially
Notes
  1. Shocked rocks are overlain by unshocked carbonate breccias and pillow lavas. Exposed shatter cones observed at the North Pole Dome (Kirkland et al. 2025)
Drilled? No
Target Type Mixed
Notes
  1. The target rock consists of ultramafic to mafic volcanic rocks (Warrawoona Group, 10–15 km thick) with felsic volcaniclastic rocks and chert, showing weak metamorphism and hydrothermal alteration. In the North Pole Dome, the 2–3 km thick Mount Ada Basalt includes a 20 m sedimentary unit (Antarctic Creek Member) of silicified and carbonate-altered volcaniclastic rocks, chert, and jaspilite, with dolerite intrusions. (Kirkland et al. 2025)
Sub-Type Sandstone
Apparent Crater Diameter (km) ~ 16 km
Age (Ma) < 2710
Notes :
  1. The presence of shatter cones in the Mount Roe Basalt provides an unambiguous stratigraphic crosscutting age constraint. Based on observations of bedrock features, the best maximum age constraint is <2.71 Ga. The minimum age is unknown but has been broadly constrained by its erosional unroofing history. The Miralga impact event occurred between 2.71 and 0.4 Ga. (Brenner et al. 2025)

Method :
  1. Stratigraphy / Geochronology
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
N/A
Erosion
7
  1. Crater shape is heavily eroded and possibly reworked from later impacts, however, shatter cones are exceptionally well persevered (Kirkland et al. 2025).
  2. Shatter cone orientation patterns suggest the removal of the upper ~3 km of the impact structure by erosion (Brenner et al. 2025)
Final Rim Diameter
Unknown
Apparent Rim Diameter
~ 16 km
  1. Speculation based on assumed central uplift and apparent spatial distribution of autochthonous shatter cones occurring in the inner ~40% of the crater (Brenner et al. 2025)
Rim Reliability Index
1
  1. The Antarctic Creek Member dips away from the core of the North Pole Dome which is interpreted to represent the central uplift of a large impact crater and its fill (Kirkland et al. 2025).
Crater Morphology
Complex
Central Uplift Diameter
6.4 km
Central Uplift Height
Unknown
Uplift Reliability Index
1
Structural Uplift
Unknown
Thickness of Seds
Unknown
Target Age
Unknown
Marine
No
Impactor Type
Unknown
Other Shock Metamorphism
One or more Spherule containing Layers
  1. The ACM contains one or more layers containing spherules, as well as higher stratigraphic levels implying another large distal impact ~10 million years after North Pole impact (Kirkland et al. 2025).
Shatter Cones
Yes
  1. Exceptionally well preserved shatter cones crop out continuously for at least several hundred meters. (Kirkland et al. 2025)
  2. Shatter cone-bearing basalts and dolomites of the 3.47 Ga Mount Ada Basalt are the oldest terrestrial target rocks preserving evidence of shock metamorphism, 170 million years older than shatter cone-bearing lithologies at the Vredefort impact structure (Brenner et al. 2025).
Planar Fractures
No
Planar Deformation Features
No
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
Unknown
Proximal Ejecta
Unknown
Distal Ejecta
Unknown
Dykes
Unknown
Volume of Melt
Unknown
Depth of Melting
Unknown

References

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Christopher L Kirkland, Tim E Johnson, Jonas Kaempf, Bruno V Ribeiro, Andreas Zametzer, R Hugh Smithies, Brad McDonald (2025) A Paleoarchaean impact crater in the Pilbara Craton, Western Australia, Nature Communications 16(1), p. 2224, url, doi:10.1038/s41467-025-57558-3

Alec R Brenner, Aaron J Cavosie, Jasmine Palma-Gomez, Joanna Li, Sophie-An Kingsbury Lee, Roger R Fu (2025) Geology and Mars analog potential of the <2.7-billion-year-old Miralga impact structure, North Pole Dome, Pilbara Craton, Australia, Science Advances 11(28), p. eadu5379, American Association for the Advancement of Science, url, doi:10.1126/sciadv.adu5379