Wednesday, September 29, 2010

Location, location, location

In the Egyptian desert near the Gilf Kebir region at co-ordinates (google earth, look for the end of two long ridges) 22d 1'6.03"N 26d 5'15. 76"E is this wonderful 45 metre wide and 16 metre deep meteorite crater in pristine condition, known as Gebel Kamil.

Scientists believe the impact was a 1.3 metre wide solid iron meteorite weighing 5000 to 10,000 kilograms hitting the earth at a speed exceeding 3.5 kilometres a second.
The impact would have generated a fireball and plume visible over 1000 kilometres.
This is considered a small impact event and the crater is important as, up to now, it was thought a metallic object of this size would beak into smaller pieces before impact. The fact that it stayed intact with the exception of an 83kg chunk found 200 metres away from the crater, means a change of thinking about the destructive power of small impacts instead of concentrating on larger "end of all life" events.

The crater was first noticed by Vincenzo de Michele who was studying earth satellite photographs for ruins of palaeolithic villages. And Egyptian/Italian expedition to the site was amazed to find it in such a well preserved conditon that even the splatter rays of ejected materials were visible. Crater ejecta rays don't go towards the centre of a crater but converge on a point at the rim or just outside it and are used to plot the direction and angle of impact.

Gebel Kamil is considered the best preserved crater so far discovered on earth. Looking at the image above, it is almost lunar like. It's also a young crater as the team found ejected bedrock material overlying prehistoric structures in the area. The geochronology is still being determined but it's les than 10,000 years old, maybe even less than 5,000 when the land became too arid for humans. If less than 5,000 years then it could have been witnessed by prehistoric people and archaeologists are hoping to fix the date by investigating nearby settlements.

The crater was discovered in 2008, explored in 2010. The research team collected over 1,000 kgs of metallic meteorite fragments. The more they collect the better to estimate the size of the meteorite but the market for meteorite rocks is booming and already bits of the Kamil impact are on the market. Once they disappear into private collections, the information they contain is lost to science.

As with archaeological looting, where an object is found, its condition and how many other fragments surround it, is vital to any study.

In trying to protect Gebel Kamil, the exploration team want it listed as a protected site by UNESCO with Egypt preserving not only the crater area but the fragments scattered over the surrounding area.


Jayne said...

That would have certainly screwed up someone's day.

JahTeh said...

Jayne, you realize what hit was the size of a small fridge or a large me, just to give you an idea of the damage a small impact can do.
Of course, me hitting the ground at that speed might have done more damage and put a larger hole in me.

River said...

I notice these things always hit remote areas. Good thing too, just imagine the damage such an impact would inflict on my backyard.

R.H. said...

How long before some Arab developer puts water in it and calls it Kamil Lakes?
There's a letter in the Herald Sun this week from some goose living in "Garden Lakes". That's just too much. You can get away with "Brimbank Gardens" maybe, or "Taylors Lakes" (both flat, barren, miles from anywhere) but should never heap the bullshit too high.

Middle Child said...

Its really interesting to read this stuff - and find out things you never would have ...good post