Woodleigh crater facts for kids
 Location in Western Australia
|
|
| Impact crater/structure | |
|---|---|
| Confidence | Confirmed |
| Diameter | 60–160 km (37–99 mi) |
| Age | 364 ± 8 Ma Late Devonian to Early Carboniferous |
| Exposed | No |
| Drilled | Yes |
| Location | |
| Location | Gascoyne |
| Coordinates | 26°3′S 114°40′E / 26.050°S 114.667°E |
| Country | Australia |
| State | Western Australia |
| District | Gascoyne |
The Woodleigh crater is a huge meteorite impact crater located in Western Australia. It's hidden deep underground, centered near Woodleigh Station, east of Shark Bay in the Gascoyne area. Scientists first announced its discovery on April 15, 2000. A team of four experts from the Geological Survey of Western Australia and the Australian National University, led by Arthur J. Mory, shared their findings.
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What is the Woodleigh Crater?
This crater is not visible on the surface, which makes it tricky to measure its exact size. When it was first discovered in 2000, scientists thought it might be as wide as 120 kilometers (about 75 miles). If that's true, it would be one of the largest confirmed impact structures on Earth!
However, some studies suggest it might be smaller, perhaps around 60 kilometers (37 miles) wide. A more recent study from 2010 suggests the crater could be anywhere from 60 to 160 kilometers (37 to 99 miles) or even larger.
What Caused the Woodleigh Crater?
A giant space rock, like an asteroid or a comet, crashed into Earth to create the Woodleigh crater. If the crater is 120 kilometers wide, the object that hit Earth would have been about 5 to 6 kilometers (3 to 3.7 miles) across. If the crater is 160 kilometers wide, the space rock could have been 6 to 12 kilometers (3.7 to 7.5 miles) wide! That's incredibly huge!
How Was the Crater Found?
Even though the crater is hidden, scientists found clues deep underground. In the late 1970s, drilling activities for other purposes accidentally hit a raised area in the center of the crater. This central uplift is about 20 kilometers (12 miles) wide.
However, no one realized it was part of an impact crater until 1997. That's when a special survey using gravity measurements helped scientists understand the unusual underground structure.
Proof of a Giant Impact
In 1999, scientists took a new core sample from the ground. Inside this sample, they found tiny pieces of melted glass, broken rocks called breccia, and a special kind of quartz called shocked quartz. These materials only form under extreme pressure, like 100,000 times the normal air pressure at sea level!
These pressures are much, much higher than what volcanoes or earthquakes can create. Only a massive impact from a space object could have caused such conditions. In 2018, scientists found an extremely rare mineral called reidite in another drill sample. Finding reidite strongly supports the idea that the Woodleigh crater is over 100 kilometers wide, possibly making it the largest in Australia.
When Did the Impact Happen?
Scientists now believe the Woodleigh impact happened about 364 million years ago. This was during a time period known as the Late Devonian period. This time roughly matches up with a major event called the Late Devonian extinction, when many types of plants and animals disappeared from Earth.
Some scientists wonder if this extinction event was caused by one or more large impacts. There's evidence of other big impacts around the same time, like the East Warburton Basin crater. So, if impacts were involved in the extinction, it might have been a combination of several large crashes.
Other Australian Craters
Australia has more than two dozen known impact craters. The Woodleigh crater is one of the three largest, along with the Acraman crater and the Tookoonooka crater. There's also another nearby structure called the Gnargoo structure, which looks very similar to Woodleigh and might also be an impact crater.
