Strangways is a large

impact structure An impact structure is a generally circular or craterlike geologic structure of deformed bedrock or sediment produced by impact on a planetary surface, whatever the stage of erosion of the structure. In contrast, an impact crater is the surface ...

, the eroded remnant of a former impact crater, located in the

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 ...

about east-south-east of the town of Mataranka. It was named after the nearby Strangways River. The location is remote and difficult to access. Its age has been determined as approximately 646 Ma.

Description

The circular topographic feature that marks the site was originally thought to be volcanic, with an impact origin first proposed in 1971 after the discovery of evidence diagnostic of impact including shatter cones and

shocked quartz Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. These pla ...

.
The circular topographic feature is about in diameter and lies within Mesoproterozoic

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s of the

McArthur Basin The McArthur Basin is a large intracratonic sedimentary basin in northern Australia, with an exposed area of about 180,000 km2. Most of it lies within the northeastern Northern Territory, but extends over the border into the state of Qu ...

. However, this is only a relic of the original crater after considerable erosion. Estimates of the original rim diameter vary between different researchers in the range ;Abstract
br/> the Earth Impact Database prefers a diameter of . The age of the impact event has been determined at 646 ± 42 Ma ( Neoproterozoic) based on

radiometric dating Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares t ...

of impact melt rocks.Abstract
br/> In 1996, the crater's site was listed on the now-defunct

Register of the National Estate The Register of the National Estate was a heritage register that listed natural and cultural heritage places in Australia that was closed in 2007. Phasing out began in 2003, when the Australian National Heritage List and the Commonwealth Heritag ...

References

{{Impact cratering on Earth Impact craters of the Northern Territory Proterozoic impact craters Precambrian Australia Geology of the Northern Territory Northern Territory places listed on the defunct Register of the National Estate

Description

See also

References