Wolf Creek Crater is a huge crater on the edge of the Great Sandy Desert, a little known desert in Western Australia. It is currently 853 m in diameter and 46 m deep. The crater is thought to have been twice as deep when it was formed, but has filled in with sand and the rim has been eroded over the centuries. Very few samples have been found of the original meteorite. The few shale balls that have been found are compromised of iron oxide. Some have weighed as much as 250 kg, while others are much smaller. The walls of the crater are mostly made of quartzite rock. The crater is surrounded by Wolfe Creek Crater National Park. The park is 1,854 km northeast of the Austrailian city of Perth.
It is thought that the meteorite that formed Wolfe Creek Crater had a mass of about 50,000 metric tonnes and impacted about 300,000 years ago. Geologists estimate that it struck the Earth at an estimated 15 km per second. They also conclude that the impact shattered rocks well below the ground surface, and the energy from the meteorite’s rocket-fast movement changed into heat, liquefying the meteorite and the nearby rocks. The resulting explosion threw rocks and debris (ejecta) in every direction. Some of the rocks remaining in the crater result from the meteorite itself. These rocks now take the form of rusted balls of iron-shale. Occurring in clusters, these balls can weigh as much as 250 kg a piece.
The crater was known by the aboriginal peoples of the continent for centuries as Kandimalal before it was officially discovered during an aerial survey mission in 1947. The crater derives its name from a local prospector and explorer named Robert Wolfe. Mr. Wolfe founded the the town of Halls Creek and discovered the river that runs nearby, Wolfe Creek, which also lends its name to the crater. There is a large amount of subsurface water in the crater itself, so it is more heavily vegetated than the surrounding area. The water is putrid and not easily digested by humans, so it is avoided as a water source even in a desert region.
Scientists have concluded that a meteorite this large impacting the Earth today would cause thousands of deaths and billions in damage. Impact events this large are the impetus behind NASA’s Near Earth Object Program.
Here are links to what Wikipedia and the Encyclopedia Britannica have to say about Wolfe Creek Crater. There are other articles on Universe Today about great craters and Astronomy Cast has a good episode to go with this topic.
Sources:
http://earthobservatory.nasa.gov/IOTD/view.php?id=8488
http://en.wikipedia.org/wiki/Wolfe_Creek_Crater
http://neo.jpl.nasa.gov/
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