Google Earth Map Showing Meteor Impact Craters Options

[Bob Shaw]

Hum,
Well i suppose that the relatively recent date may shock a few people, and that it have been controversial a few years ago...
But, Dallas Abbott of the Lamont-Doherty Earth Observatory (LDEO) and her colleagues analysed melt water from nine samples taken from the West Antarctic Siple Dome ice core that date between 1440 and 1448 A.D. and found high values of potassium and calcium as well as impact glass, microcrystalline magnetite, minerals and five microfossils corresponding to the 1443 A.D. level.
Several pieces of evidence point to Mahuika as the source ...
http://www.earth2class.org/k12/w8_s2004/content.htm
http://www.usnews.com/usnews/culture/artic...8/8meteor_2.htm
http://abob.libs.uga.edu/bobk/ccc/cc120403.html

You obviously have a handle on these matters, so I wonder if I can send another hare out for the dogs to chase?

Are there any impact sites identified with the Australian tektites?

Bob Shaw

[edstrick]

Last I heard that a likely location for the source for the austral-asian strewn field of tektites was entirely buried under the sediments of the Meking river plains in Cambodia. Some source in that very very general area on continental crust seems required, but there's no sign of a source crater anywhere, and that's the largest area of thoroughally sediment-buried crust anywhere around.

High-resolution geophysical prospecting/maping (gravity and magnetics) would find it, but getting permission is.........

[blobrana]

but there's no sign of a source crater anywhere

Hum,
Yeah a bit of a mystery there...

Australites (and Indochinites which are indistinguishable from each other) have been dated to about 710,000 years using fission track and potassium-argon (K-Ar) dating methods; However the stratigraphic positions indicates an age of 7000 to 20,000 years BP.
From their chemical composition, both belong to the same impact event...!

The evidence seems to show a least two episodes of australite falls - one relatively recent (24,000 and 16,000 years ago) and at 710,000years. (It could be influenced by sorting by ie Early man)
Australites are also unusual in that some show that they were remelted; this may show different trajectories - sending some material into orbit...

Darwin glass from South West Tasmania has a combined K-Ar and fission track age of 730,000 +/- 40,000 years. It seems that Darwin crater was the source of both.
I would also add that it is possible that the impact crater may be part of two or more events that occurred together. Another associated impact crater could have been formed in the Indonesian region.
A larger impact crater that still has to be found...
Darwin Crater has a diameter of 1 km


Expand
(This is a possible location - can someone confirm?)
-42.249599° 145.555629°

(i`ve posted another location (42°18.39'S, 145°39.41'E) at googlehacks though)

http://www.grisda.org/origins/04076.htm

[blobrana]

Hum,
i ve just remembered another possibility for the Australites.

“An asteroid between 5 - 11 km across had broken up in the atmosphere and five large pieces had hit the Earth, creating multiple craters over an scatter ellipse area in Antarctica.
Scatter ellipses such as this accompany all such multiple impact sites, except that the Antarctic ellipse is the largest known on Earth. Of the five new impact craters, three of them are on the continental land mass and two more are in the Weddell Sea. The largest of these craters is about 322km by 322km.
The Antarctic scatter ellipse is of enormous size by Earth standards, measuring some 2,092 kilometres by 3,862 kilometres. Melted rocky debris, blasted from such meteoroid craters upon impact and explosion, and known as tektites, may have been carried thousands of kilometres from the impact site. Such tektites, called australites, are found in large strewn fields in Australia some 5600 kilometres from the largest proposed impact sites in the Ross Sea region.

The impacts occurred roughly 780,000 years ago during an ice age. When the impacts hit, they would have melted through the ice and through the crust below.”

Read more (PDF)

Web link:

Another weblink:

A recent weblink:

[blobrana]

Hum,
just for the record - (i can`t find this information anywhere on the net!)...The location of Darwin Crater is at

Latitude = -42.30483 Longitude = 145.65883

Small IMAGE

[Bob Shaw]

Hum,
just for the record - (i can`t find this information anywhere on the net!)...The location of Darwin Crater is at

Latitude = -42.30483 Longitude = 145.65883

Small IMAGE

Blobrana:

I have several tektites from both fields (Australites and Indochinites), which are always a joy to tell people about! When asked to identify the object, the most common reaction is 'fossilised turd'. I have an ace up my sleeve in such cases to deal with smartarses - a genuine coprolite, a fossilised turtle poo!

Bob Shaw

[Guest_DonPMitchell_*]

You might remember this photo of a meteor, taken a few years ago. I saved the picture, but I didn't save any information about who took it or where.

[attachment=5911:attachment]

I just now tried to locate the Tunguska impact in Siberia. This was an airburst impact, perhaps of an icy object, that leveled trees with its shockwave. You can't really see anything there now, at the resolution of Google Earth:

[attachment=5914:attachment] [attachment=5913:attachment]

[Bob Shaw]

You might remember this photo of a meteor, taken a few years ago. I saved the picture, but I didn't save any information about who took it or where.

Don:

I seem to remember that picture of the 'airburst' turned up on APOD, but then got debunked!

Bob Shaw

[blobrana]

I seem to remember that picture of the 'airburst' turned up on APOD, but then got debunked!

Hum,
looked real to me...

http://news.bbc.co.uk/1/hi/wales/south_east/3155928.stm

[Guest_DonPMitchell_*]

Don:

I seem to remember that picture of the 'airburst' turned up on APOD, but then got debunked!

Bob Shaw

Intersting, I saw the first story on BBC. Just googling around, it appears that this is an unresolved topic. First NASA said it was an meteor, a "sofa sized rock". Then a few days later they announced it was just the sun shining on a jet contrail (doesn't look like that to me). Then a second photo of the object turned up, taken by a man in Scotland:

[attachment=5921:attachment]

And here is Burnett's second photo:

[attachment=5922:attachment]

In the photo from Scotland, the curve of the trail makes me think it is not a meteor. Here's more what they should look like:

[attachment=5923:attachment]

[helvick]

I've seen one nighttime fairly large bolide - can't remember precisely when cos I was a lot younger (early 1980's can't remember which one exactly) but it was summertime (August I think in the Northern hemisphere) around 11:00 - 11:30 BST so it was reasonably dark. I initially thought it was an emergency flare of some sort but almost immediately realised that it was incredibly bright - at least full moon bright and more than bright enough to cast very distinct shadows over as far as I could see. It looked exactly like your last picture and nothing like the first - intense blue\white with a clearly defined teardrop shape. I can't recall how long it remained visible - probably no more than a couple of seconds but it was much longer than a typical meteor streak, sufficiently long for me to react to it and stare for a while and realise that this was lighting up the entire coastline - I recall that I could see places more than 10 miles away clearly however in hindsight that seems a bit fancyful. It was an awe inspiring sight though, not quite as awesome as a full eclipse must be, but it really does make you feel quite small and insignificant.

It was mentioned in the Irish news media the following day that Astronomy ireland were looking for anyone who had seen it who could give them any specifics on it's position but at the time I didn't know enough about such things to be of any help.

Anyway to return from that aside - my gut feel (uh-oh Shaka will be after me) is that the "dumped fuel igniting in a jet exhaust" explanation that is buried in the comments on the BBC article seems most probable to me. But this is just a gut feel - I've no personal experience of igniting jet fuel at high altitude and velocity (unfortunately).

[Bob Shaw]

I saw a *major* fireball whilst out one night in the countryside near Dumfries, in SW Scotland in 1972. The damn thing gave me such a fright that I fell off my bicycle! I understand that it also fell in Northern Ireland, prompting a security scare. It was certainly very bright, and lit up the whole sky - though my fading memory insists that the ground was still dark.

Funny that Ireland should be so lucky!

Bob Shaw

[dvandorn]

Several years ago, I was driving through Wisconsin at about 2 a.m. In the wilds of Wisconsin, it gets pretty dark out, and there was no Moon that night.

I saw a fireball that came over the horizon just at the left extremity of my windshield view and then arced across the sky, directly in my field of view. It was bright blue-white, leaving a greenish trail behind it. As it approached the far horizon, almost exactly aimed at the right visual limit of the windshield, it appeared to fragment and explode into sparkles.

There was, as I say, no Moon, so this thing looked very bright to me, but it might not have been super-bright. (I did see it very clearly over the glare of my headlights on the road ahead of me, though.) One thing I do recall, the *entire* trail glowed with a greenish glow for several seconds after the event. It was too dark to see a contrail after that glow dissipated, I'm sorry to say. The area where the fireball seemed to explode seemed to glow for several more seconds than the rest of the trail, maybe for as long as 10 or 15 seconds.

I'd guess that the whole traverse of my visual field took maybe one and a half seconds -- too fast for a re-entering satellite.

That was the brightest fireball I've ever seen, although the "meteor storm" a few years back was one of the most fascinating meteor events I've ever seen. You'd get clusters of trails, not just the occasional streak. I was looking directly at the source point in the sky when a starburst of five meteors flashed towards me, making a near-perfect five-pointed star in the sky... That was simply spectacular!

-the other Doug

[blobrana]

Hum,
Northern Norway was hit with an meteorite impact comparable to the atomic bomb on Wednesday, 7th June, 2006.
For several seconds, residents of the northern part of Troms and the western areas of Finnmark saw a ball of fire crossing the sky.
A few minutes later an impact was heard and geophysics and seismology stations in Karasjok registered a powerful sound and seismic disturbances at 02:13.25 a.m.
The meteorite hit a mountainside in Reisadalen in North Troms, and was probably the largest known to have struck Norway.

Latitude 69.498379° Longitude 21.428999°
(As the actual impact site hasn't been found the attached image is centred on Reisadalen.)

Attached thumbnail(s)

 

[Rob Pinnegar]

Guess all the local universities will be sending people up there to look for the crater! That would be an interesting trip. At least it's at the right time of year, eh? They'll be able to look for it 24 hours a day.