Darwin Crater is a suspected
meteorite
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...
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 ...
in
Western
Western may refer to:
Places
*Western, Nebraska, a village in the US
*Western, New York, a town in the US
*Western Creek, Tasmania, a locality in Australia
*Western Junction, Tasmania, a locality in Australia
*Western world, countries that id ...
Tasmania
)
, nickname =
, image_map = Tasmania in Australia.svg
, map_caption = Location of Tasmania in AustraliaCoordinates:
, subdivision_type = Country
, subdi ...
about south of
Queenstown, just within the
Franklin-Gordon Wild Rivers National Park
Franklin-Gordon Wild Rivers is a national park in Tasmania, 117 km west of Hobart. It is named after the two main river systems lying within the bounds of the park - the Franklin River and the Gordon River.
Location
The Franklin-Gordon Wi ...
. The crater is expressed as a rimless circular flat-floored depression, in diameter, within mountainous and heavily forested terrain. It is east of the
West Coast Range
The West Coast Range is a mountain range located in the West Coast region of Tasmania, Australia.
The range lies to the west and north of the main parts of the Franklin-Gordon Wild Rivers National Park.
The range has had a significant number ...
and the former
North Mount Lyell Railway
The North Mount Lyell Railway was built to operate between the North Mount Lyell mine in West Coast, Tasmania, West Coast Tasmania and Pillinger, Tasmania, Pillinger in the Kelly Basin of Macquarie Harbour.
History
At the start of the Twenti ...
formation.
Discovery and description
The crater was discovered by the
geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...
R. J. Ford in 1972, after a search for the source of
Darwin glass
Darwin glass is a natural glass found south of Queenstown in West Coast, Tasmania. It takes its name from Mount Darwin in the West Coast Range, where it was first reported, and later gave its name to Darwin Crater, a probable impact crater, and ...
,
an
impact glass
Impactite is rock created or modified by one or more impacts of a meteorite. Impactites are considered metamorphic rock, because their source materials were modified by the heat and pressure of the impact. On Earth, impactites consist primarily o ...
found over more than of southwestern Tasmania.
Geophysical
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som ...
investigations and
drilling
Drilling is a cutting process where a drill bit is spun to cut a hole of circular cross-section in solid materials. The drill bit is usually a rotary cutting tool, often multi-point. The bit is pressed against the work-piece and rotated at ra ...
have shown that the crater is filled with up to of
breccia
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix.
The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of di ...
capped by
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
lake
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
s.
Although definitive proof of an impact origin of the crater is lacking, the impact hypothesis is strongly supported by the relationship of the glass to the crater, as well as the
stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks.
Stratigrap ...
and
deformation
Deformation can refer to:
* Deformation (engineering), changes in an object's shape or form due to the application of a force or forces.
** Deformation (physics), such changes considered and analyzed as displacements of continuum bodies.
* Defor ...
of the crater-filling material.
If the crater is indeed the source of the glass, the age of Darwin Crater is 816,000 ± 7,000 years—the age of Darwin glass as determined by
argon–argon dating
Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer ...
method.
Carbonaceous inclusions have been found for the first time in Darwin glass: these have been shown to be biomarkers which survived the Darwin impact and are representative of plant species in the local ecosystem—including cellulose, lignin, aliphatic biopolymer and protein remnants.
Access
While there is a trail leading to the crater, personal recounts note that it is unmaintained, overgrown and boggy in places.
Gallery
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 ...
*
Protected areas of Tasmania
Protected areas of Tasmania consist of protected areas located within Tasmania and its immediate onshore waters, including Macquarie Island. It includes areas of crown land (withheld land) managed by Tasmanian Government agencies as well as priv ...
References
External links
Tasmania Parks & Wildlife Service
Further reading
{{Impact cratering on Earth
Impact craters of Tasmania
Pleistocene impact craters
Pleistocene Australia
Western Tasmania