Goat Paddock - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 18° 20' 11" S; 126° 40' 27" E
Notes
  1. The Kimberley district of Western Australia.
Country Australia
Region Western Australia
Date Confirmed 1980
Notes
  1. Shatter cones, breccias and impact melt confirm this impact site (Milton et al., 1980).
Buried? No
Notes
  1. ~210 m of lacustrine sediments containing Eocene microflora (Milton et al., 1980).
Drilled? Yes
Notes
  1. 2 drill holes, one at the centre and one about 1.25 km NE of the centre, penetrate 210 m of lacustrine sediments before entering brecciated sandstone (Harms et al., 1980).
Target Type Sedimentary
Notes
  1. Proterozoic sandstones and siltstone (Milton et al., 1980).
Sub-Type Sandstone, Siltstone
Apparent Crater Diameter (km) 5 km
Age (Ma) 48 - 56
Notes :
  1. The crater floor is covered with lacustrine sediments containing Eocene microflora. Core samples of crater-fill indicate an Early Eocene age (Milton et al., 1980).

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
5
  1. Eroded with ejecta removed and with a largely degraded rim (Harms et al., 1980).
Final Rim Diameter
Unknown
Apparent Rim Diameter
5 km
  1. Dimensions poorly known, from diagram of (Harms et al., 1980). The diameter measured from the upper edge of the topographic rim is about 5.8 km east – west and 6.3 km north – south (Milton and MacDonald, 2005).
Rim Reliability Index
3
  1. Consists of a circular plain bounded for most of its circumference by a raised rim, 100-150 m high (Harms et al., 1980). No central peak present. "The nearly equal depths suggest the absence of a central peak" (Harms et al., 1980). According to (Milton and MacDonald, 2005), Goat Paddock is a transitional crater as it does not show neither a deep-bowl shape nor a central peak, its depth/diameter ratio and slumped rim.
Crater Morphology
Transitional
Central Uplift Diameter
Nokm
Central Uplift Height
No
Uplift Reliability Index
2
Structural Uplift
Unknown
Thickness of Seds
Target Age
Precambrian
Marine
No
Impactor Type
Other Shock Metamorphism
No
Shatter Cones
Yes
  1. Well-developed shatter cones were discovered in drillcore samples from the central part of the structure; a few clasts of poorly developed shatter cones were also found in the breccia at the crater wall (Harms et al., 1980). Shatter cones occur in sandstone (Fig. 5C) (Milton and Macdonald, 2005).
Planar Fractures
Yes
  1. PF in quartz grains (Milton et al., 2004)
Planar Deformation Features
Yes
  1. PDF in quartz grains (Harms et al., 1980).
Diaplectic Glass
Yes
  1. Vesiculated silica glass (Milton et al., 2004).
Coesite
No
  1. To date, coesite or stishovite have not been found" (Harms et al., 1980).
Stisovite
No
  1. (Harms et al., 1980).
Crater Fill
LB, MB
  1. "The disturbed beds show a high degree of fracturing everywhere and grade into breccia inside and particularly outside the rim crest...we are uncertain whether the breccia at high levels on the rim includes throwout (debris ejected ballistically)" (Harms et al., 1980). "A small patch of melt breccia was found in one creek between the base of the wall and the innermost bedrock outcrop" via (Harms et al., 1980). Breccia dikes (Figure 2c) (Harms et al., 1980). (Milton and MacDonald, 2005) describe small exposures of "suevite" in the southern sector of the crater. It consists of target rock clasts with a wide range of shock pressures, "flow-banded and vesiculated glass" clasts. According to the descriptions, some of the glass "wrap around other fragments and form ropy microtextures, indicating that some of the glassy fragmens were still plastic at the time of emplacement". Glass in the groundmass? Melt rocks?
Proximal Ejecta
LB
Distal Ejecta
Dykes
LB
Volume of Melt
Depth of Melting

References

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D J Milton (1979) Impact craters of Australia, International Union of Geodesy and Geophysics - XVII General Assembly Abstracts., p. 1-211

Daniel J Milton, R F Fudali, John Ferguson, Lynton Jaques, Henry E Holt, Elisabeth C Kosters (1980) Goat Paddock, Western Australia: An impact crater near the simple-complex transition, NASA Technical Memorandum(82385), p. 125-126, National Aeronautics and Space Administration (NASA), Washington, DC

J E Harms, D J Milton, J Ferguson, D J Gilbert, W K Harris, B Goleby (1980) Goat Paddock cryptoexplosion crater, Western Australia, Nature (London) 286(5774), p. 704-706, Macmillan Journals, London, url

D J Milton, J Ferguson, R F Fudali (1980) Goat Paddock impact crater, Western Australia, Meteoritics 15(4), Carleton B Moore (ed.), p. 33, Arizona State University, Center for Meteorite Studies, Tempe, AZ, url

E M Shoemaker, C S Shoemaker (1985) Impact structures of Western Australia, Meteoritics 20(4), Carleton B Moore (ed.), p. 754-756, Arizona State University, Center for Meteorite Studies, Tempe, AZ

R A F Grieve, C A Wood, J B Garvin, G McLaughlin, J F McHone (1988) Impact Craters in Australia, Astronaut's Guide to Terrestrial Impact Craters, R.~A.~F. Grieve, C.~A. Wood, J.~B. Garvin, G McLaughlin, J.~F. McHone Jr. (ed.), p. 67, url

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

D J Milton, F A Macdonald, A Y Glikson, P W Haines (2005) Goat Paddock, Western Australia: An impact crater near the simple-complex transition, Australian Journal of Earth Sciences 52(4-5), p. 689-697, Blackwell Scientific Publications for the Geological Society of Australia, Melbourne, Victoria, url, doi:10.1080/08120090500170435

R L Paul, J-P Muller, J B Murray (2006) An assessment of crater erosional histories on the Earth and Mars using digital terrain models., European Planetary Science Congress, p. 635, url