Within Western Australia there are a number of geologic oddities, owing to much of the
host rock being 2 to 3 billion years in age.
This includes bright red banded iron formations, some of which even have the gemstone tiger's
eye interspersed with them in what is known as "tiger iron".
The area also still has a cluster of one of the planet's oldest living organisms called
stromatolites.
These mounds are indeed alive and consist of layers of cyanobacteria.
Because of the general old age of the rock, Western Australia has a number of very large
impact craters.
However, it also has a number of more recent craters which formed in the last 200,000 years.
One of these craters was not discovered until 2007, when Dr Arthur Hickman discovered a
circular depression in the ground while browsing Google Earth.
After a short drill program was done, this structure was confirmed as a very young impact
crater.
Now known as Hickman Crater, this feature measures 260 meters wide and 10 meters deep.
Despite its highly eroded appearance, it is one of the nation's youngest impact structures.
We know that this crater has an age of between 10,000 and 100,000 years old.
A more recent dating attempt pinned an age of 50,000 years, although it used a methodology
which had a high margin of error, meaning that this crater is somewhere in the 50,000
to 100,000 year old range.
This video will assume that the figure of 50,000 years old is the crater's true age.
Approximately 50,000 years ago, a small mass of rock was on a collision course with earth.
The asteroid in question was approximately 11 meters or 36 feet wide, and represented
a segment of rock which originated from the core of a much larger asteroid.
It was unusually dense, consisting of mainly iron and nickel but also with elevated levels
of platinum and iridium.
Although exactly where this asteroid first formed is unknown, its unusually slow impact
speed suggested an origin in the inner asteroid belt.
As this asteroid made its final approach towards the planet, it began to further accelerate
due to the pull of Earth's gravity.
Accelerating to 11 kilometers per second or 25,000 miles per hour, it entered the upper
atmosphere.
Due to its small size, it began to burn up.
However, due to its composition, it did not immediately fragment.
Instead, it remained relatively intact until it impacted the ground in a remote section
of Australia at an angle of 45 degrees.
This impact occurred heading in the southwest direction, generating a powerful explosion
equivalent in energy to the detonation of 10 kilotons of TNT.
This quickly vaporized the impact site, and generated a powerful shockwave which expanded
outwards in all directions.
Any creatures within a 750 meter radius would have been instantly wiped out due to a wind
speed exceeding 800 kilometers per hour.
However, as this blastwave continued it quickly lost energy.
Any trees present within a 2200 meter radius were flattened, while at 3500 meters distant
from the impact site only moderate tree damage occurred.
At a distance of 10 kilometers this impact would have been relatively safe to view as
you would have experienced only an 18 kilometer per hour shockwave.
This impact generated a magnitude 3.3 earthquake, and generated a sound loud enough to be heard
within a 500 kilometer radius.
Fragments of the iron meteorite were largely dispersed over a 10 square kilometer area
near the crater, although some fragments may have been flung even further during the impact
towards the southwest.
Today, this area can be accessed via a series of dirt roads, although third party access
needs to be first granted from those who own mining claims in the vicinity.
Since the crater has a bowl like shape, whatever minimal rainfall the area received pools there
for extended periods of time, allowing for an increased level of vegetation within the
crater.
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