Yarrabubba impact structure facts for kids
 Location in Western Australia
|
|
| Impact crater/structure | |
|---|---|
| Confidence | Confirmed |
| Diameter | 30–70 km (19–43 mi) |
| Age | 2229 ± 5 Ma Rhyacian, Paleoproterozoic |
| Exposed | Yes |
| Drilled | No |
| Location | |
| Location | Yilgarn Craton |
| Coordinates | 27°10′56″S 118°50′04″E / 27.18222°S 118.83444°E |
| Country | Australia |
| State | Western Australia |
| Municipality | Shire of Meekatharra |
The Yarrabubba impact structure is what's left of a very old impact crater in Western Australia. It's located in a place called the Yilgarn Craton, near a spot known as Yarrabubba Station. This area is between the towns of Sandstone and Meekatharra. What makes Yarrabubba special is its age: at 2.229 billion years old, it's the oldest known impact structure on Earth!
Contents
What is the Yarrabubba Impact Structure?
Even though the original edge of the crater has completely worn away over billions of years, scientists know where its center was. This center point is near a rock formation called Barlangi Rock. You can't see the crater's shape from the air or in satellite pictures anymore because it's so old and eroded.
How Do We Know It's an Impact Crater?
Scientists found proof of a huge impact by looking at rocks in the area. They discovered special minerals like shocked quartz and shatter cones. These are only formed when something hits the Earth with incredible force, like a meteor. These special rocks were found in granite outcrops, which are thought to be close to the original center of the crater. Scientists also used geophysical data, which involves studying the Earth's physical properties, to learn more about the structure hidden beneath the surface.
How Big Was the Original Crater?
It's hard to say exactly how big the original crater was because so much of it is gone. However, experts estimate its diameter was somewhere between 30 and 70 kilometers (about 19 to 43 miles) across. To understand how such a crater might have formed, scientists used computer simulations. They imagined a space rock about 7 kilometers (4.3 miles) wide crashing into a thick ice sheet, about 2 kilometers (1.2 miles) deep, that covered solid granite rock. This simulation created a crater size that matches what they believe the Yarrabubba crater was like.
How Old is the Yarrabubba Crater?
The Yarrabubba impact happened about 2,229 million years ago, plus or minus 5 million years. This makes it the oldest confirmed impact structure on our planet. This event took place during a time called the early Rhyacian period, which was around the end of a major ice age known as the Huronian glaciation.
How Scientists Found the Age
To figure out the crater's age, scientists studied tiny, ancient crystals found within the crater. These crystals were from minerals called zircon and monazite. They used a method called uranium-lead dating. This method looks at how much uranium in the crystals has changed into lead over time. By carefully analyzing these changes, scientists could accurately determine when the impact happened and how old the crater truly is.
See also
- List of impact craters on Earth
- Impact crater
