Kelly West Crater
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Kelly West is a deeply eroded
impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...
situated in the central
Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...
,
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
. It was discovered during Government geological mapping and first reported in 1973, the evidence for impact coming principally from an abundance of
shatter cone Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. They are evidence that the rock has been subjected to a shock with pressures in the rang ...
s at the site.


Description

The surface expression of Kelly West comprises a circular hill of
Palaeoproterozoic The Paleoproterozoic Era (;, also spelled Palaeoproterozoic), spanning the time period from (2.5–1.6  Ga), is the first of the three sub-divisions (eras) of the Proterozoic Eon. The Paleoproterozoic is also the longest era of the Earth's ...
quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tect ...
about in diameter, interpreted as a central uplift of a larger complex impact crater.
Recent geophysical interpretation suggests an original crater diameter of ,
less than earlier estimates of about . The age is poorly constrained, but must be older than Middle
Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...
because sedimentary rocks of this age overlie the central uplift and were not deformed by the impact event.


See also

*
List of impact craters in Australia This list includes all 27 confirmed impact craters in Australia as listed in the Earth Impact Database.Bevan, Alex. and Ken McNamara (2009) ''Australia's meteorite craters'' Welshpool, W. A. : Western Australian Museum, 2nd ed. (pbk.) and oth ...


References

{{DEFAULTSORT:Kelly West Crater Impact craters of the Northern Territory Proterozoic impact craters Precambrian Australia Geology of the Northern Territory