Geophysical and structural criteria for the identification of buried impact structures, with reference to Australia

Glikson, Andrew and Uysal, I. Tonguç (2013) Geophysical and structural criteria for the identification of buried impact structures, with reference to Australia. Earth-Science Reviews, 125 114-122. doi:10.1016/j.earscirev.2013.07.002


Author Glikson, Andrew
Uysal, I. Tonguç
Title Geophysical and structural criteria for the identification of buried impact structures, with reference to Australia
Journal name Earth-Science Reviews   Check publisher's open access policy
ISSN 0012-8252
1872-6828
Publication date 2013-10
Year available 2013
Sub-type Critical review of research, literature review, critical commentary
DOI 10.1016/j.earscirev.2013.07.002
Open Access Status
Volume 125
Start page 114
End page 122
Total pages 9
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2014
Language eng
Subject 1900 Earth and Planetary Sciences
Abstract The discovery of large asteroid impact structures, likely and possible impact structures, onshore and offshore the Australian continent (Woodleigh [120. km; ~. 360. Ma], Gnargoo [75. km; Lower Permian - upper Cretaceous], Tookoonooka [55-65. km; ~. 125. Ma], Talundilly [~. 84. km; ~. 125. Ma], Mount Ashmore [>. 100. km; end-Eocene] and Warburton twin structures [>. 400. km; pre-end Carboniferous]) requires re-examination of the diagnostic criteria used for their identification. Bouguer anomalies of established impact structures (Chicxulub [170. km; 64.98. ±. 0.05. Ma], Woodleigh impact structure and Gnargoo probable impact structure display a unique structural architecture where pre-impact structural ridges are intersected and truncated by the outer ring of the circular structure. Seismic reflection data outline circular central uplift domes, basement plugs and rim synclines. Sharp circular seismic tomography anomalies indicate low velocity columns under both the Woodleigh impact structure and Warburton probable impact, hinting at deep crustal fracturing. Deformed, curved and clouded intra-crystalline planar deformation features in quartz (Qz/PDFs), displaying Miller indices ({10-11}, {10-12}, {10-13}) diagnostic of shock metamorphism, abound around exposed established impact structures (Vredefort [298. km; 2023. ±. 4. Ma], Sudbury [~. 250. km; 1850. ±. 3. Ma], Charlevoix [54. km; 342. ±. 15. Ma], Manicouagan [100. km; 214. ±. 1. Ma]), Tookoonooka and Talundilly). Deformed Qz/PDFs allow recognition of shock metamorphism in buried impact structures, where original Qz/PDFs were bent, recrystallized and/or clouded during formation of the central uplift and hydrothermal activity triggered by the impact. Planar deformation in quartz can also occur in explosive pyroclastic units but are limited to Boehm lamella (Brazil twins) with single lamella sets {0001}. It has been suggested that a class of microstructures in quartz, referred to as metamorphic deformation lamella (Qz/MDL), occur in endogenic tectonic-metamorphic terrains. However, no type locality has been established for Qz/MDL of non-impact origin.
Keyword Asteroid
Australia
Buried
Impact
Planar deformation features
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: School of Mechanical & Mining Engineering Publications
Official 2014 Collection
 
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