Amelia Creek - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 20° 50' 35" S; 134° 53' 19" E
Notes
  1. Amelia Creek crater is located in the Davenport Ranges.
Country Australia
Region Northern Territory
Date Confirmed 2003
Notes
  1. Confirmed by the presence of shatter cones and impact breccias in the central region, as well as shatter cones and other shock metamorphic features on the southern side of the structure (Macdonald and Mitchell, 2003).
Buried? No
Notes
  1. (Macdonald and Mitchell, 2003)
Drilled? No
Target Type Mixed
Notes
  1. Precambrian sediments and volcanics.
Sub-Type Sedimentary, Volcanics
Apparent Crater Diameter (km) 20 km
Age (Ma) 660 - 1660
Notes :
  1. Minimum age: ~600 Ma constrained by overlying Neoproterozoic (~600 Ma) sandstone and conglomerate (Andagera Formation) (MacDonald et al., 2005) Maximum age: ~1660 Ma constrained by age of Palaeoproterozoic target rock (Hatches Creek Group) as determined by whole rock Rb/Sr (Blake et al., 1987) (MacDonald et al., 2005)

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
7
  1. Amelia Creek impact structure is eroded below the crater floor.
Final Rim Diameter
Unknown
Apparent Rim Diameter
20 km
  1. The structure is oblique and covers an area of at least 20 x 12 km (Macdonald and Mitchell, 2003). Aeromagnetic, advanced spaceborne thermal emission and reflection radiometer (ASTER), and X-band synthetic aperture radar (X-SAR) images show an area with arcuate features at a 10 km radius to the north and south of the shock-metamorphosed rocks (Macdonald et al 2005).
Rim Reliability Index
3
  1. Presence of a central trough and syncline in place of a central uplift, formed by an extremely oblique impact event (Macdonald et al., 2005).
Crater Morphology
Complex
Central Uplift Diameter
km
Central Uplift Height
Unknown
Uplift Reliability Index
Structural Uplift
Unknown
Thickness of Seds
Target Age
Precambrian
Marine
No
Impactor Type
Other Shock Metamorphism
Feather features?
  1. (MacDonald et al., 2005) hesitates to fully commit to calling them true feather features, putting the word in quotation marks as if they are not quite feather features.
Shatter Cones
Yes
  1. Shatter cones are primarily restricted to two kilometer sized fault blocks located around the centre of the structure (Macdonald et al., 2005). Poorly (to well-) developed shatter cones occur in the Unimbra Sandstone and in felsic volcanics in the Yeeradji Sandstone of the Wauchope Subgroup (with single cones nearly a meter in length) (Macdonald et al., 2005). They are typically oriented with the apex pointing upwards and at high angles to the bedding. The surface distribution of shatter cones covers about 6 km2 in plan view. Thin-sections of shatter cones in the Unimbra Sandstone display PFs but no PDFs in quartz grains. Presence of feather texture in quartz grains.
Planar Fractures
Yes
  1. PFs found in quartz grains (Macdonald et al., 2005).
Planar Deformation Features
No
  1. Lack of PDFs in quartz may be due to deep erosion (Macdonald et al., 2005).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
  1. Due to the complex geology and heavy erosion of the area no crater-fill impactites have been reported (Macdonald et al., 2005).
Proximal Ejecta
Distal Ejecta
Dykes
Volume of Melt
Depth of Melting

References

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F A Macdonald, K Mitchell (2003) Amelia Creek, Northern Territory, Australia: A 20 × 12 Km oblique impact structure with no central uplift, Impact Cratering: Bridging the Gap Between Modeling and Observations(1155), p. 47-47, url

F A Macdonald, K Mitchell, A J Stewart (2005) Amelia Creek: a Proterozoic impact structure in the Davenport Ranges, Northern Territory, Australian Journal of Earth Sciences 52(4-5), p. 631-640, doi:10.1080/08120090500170401

I P Sweet, P W Haines, K Mitchell (2005) Matt Wilson structure: Record of an impact event of possible Early Mesoproterozoic age, Northern Territory, Australian Journal of Earth Sciences 52(4-5), p. 675-688, doi:10.1080/08120090500180988

P W Haines (2005) Impact cratering and distal ejecta: the Australian record, Australian Journal of Earth Sciences 52(4-5), p. 481-507, doi:10.1080/08120090500170351

F A MacDonald, K Mitchell, A J Stewart (2005) Amelia Creek: A Proterozoic impact structure in the Davenport Ranges, Northern Territory, Australian Journal of Earth Sciences 52(4-5), p. 631-640, doi:10.1080/08120090500170401

M H Poelchau, T Kenkmann (2011) Feather features: A low-shock-pressure indicator in quartz, Journal of Geophysical Research: Solid Earth 116(B2), p. 1-13, doi:10.1029/2010JB007803

S Staffieri, A Coletta, M L Battagliere, M Virelli (2019) Amelia Creek, Australia, Encyclopedic Atlas of Terrestrial Impact Craters, p. 225-227, Springer International Publishing, doi:10.1007/978-3-030-05451-9_58