[Bailey (OP)]

so.. its from some melted form of silica..what about the round bit and its little button centre?

[JimBob]

Bass is going to shoot me -

but since I am wearing my bullet proof armor .....

These below are glass tektites from Australia

http://tektiteinc.com/14grams.html

http://tektiteinc.com/56gramsb.html

Frethac has also posted pictures of them - http://www.thenakedscientists.com/forum/index.php?topic=28890.msg300921#msg300921 This plate is reproduced below.

http://www.fas.org/irp/imint/docs/rst/Sect18/tektite1.jpg

As well, a former professor (and a personal hero of mine) wrote an article of ejecta from impact craters


Terrestrial implication of layering, bubble shape and minerals along faults in tektite origin
Virgil E. Barnes
Bureau of Economic Geology, The University of Texas, Austin USA
Received 4 February 1964.
Geochem. Acta

Abstract
Both detrital mineral grains and minerals which crystallized in situ were first found in tektites along faults in Muong Nong-type indochinites from Kan Luang Dong, Thailand. The detrital mineral grains have the optical properties of quartz and are within the size range of quartz abundant in local soil and rock. Such a correspondence in grain size strongly implies that the tektites from Kan Luang Dong are locally derived. Layered tektites are probably the result of the accumulation in puddles of melt from flash fusion of bare patches of soil and rock. The faulting took place while the melt was very hot and the evidence for this is: (1) perfect welding of the fault-fractures with detrital grains equally embedded in the glass on either side of the welds, (2) growth of minerals along the faults, and (3) warping of the fault planes by movement of the melt following faulting.


It is my hypothesis that this is ejecta from an impact site that did not get totally melted, but only mostly melted. This piece is a bit of country rock (surface rock) ejected from the crater that is mostly glass but still retains characteristic of the original rock.

The button is formed (I am finally answering your question) in the same way as the buttons in the bottom part of the black and white picture above - by aerodynamic shaping of the partially melted rock entering the atmosphere. The pits all over it are places where material has ablated from the rock while it was reentering the atmosphere.

The fact that it is so hard, heavy and has aerodynamic shape TO ME indicate only an origin formed in the atmosphere.

[Bailey (OP)]

jb..would you be interested in having a closer look at this..ill send it to you if you like so you can have a closer look.if this was formed in the atmosphere when it was still'semi molten' i cant see how it has its current shape.

[JimBob]

Baily,

Please consider this move carefully. If you know of a friend or family member in one of university cities of Oz, they could take it to the geology department for an opinion. If you do wish to send it to me that would be wonderful. But please consider that move very carefully before you do it. There are many things that could go wrong.

[LeeE]

Hmm... I'm beginning to wonder if this might be a tektite fragment from an iron meteorite.  Those straight edges still bother me a bit though.

[RD]

Bear in mind Bailey also posted this speleothem ...
http://www.thenakedscientists.com/forum/index.php?topic=27121.msg286936#msg286936

 [ Invalid Attachment ]
http://books.google.co.uk/books?id=CxwDSfpMq2oC&printsec=frontcover&dq=Beneath+the+surface:+a+natural+history+of+Australian+caves&cd=1#v=onepage&q=stalagmite&f=false



 [ Invalid Attachment ]
http://www.thenakedscientists.com/forum/index.php?topic=29207.msg303322#msg303322

[JimBob]

its very hard,i cant scratch it with a knife..and there appears to be quartz like parts (lighter in colour) throughout the rock.im thinking it is a comglomerate of some kind,but not man made.

And bear in mind that a speleothem will not scratch a knife. A welded bit of country rock shaped a bit by air can produce this shape, texture and hardness.

From your WIkipedia reference - http://en.wikipedia.org/wiki/Speleothem

Origin and composition

Water seeping through cracks in a cave's surrounding bedrock may dissolve certain compounds, usually calcite and aragonite (both calcium carbonate), or gypsum (calcium sulfate). The rate depends on the amount of carbon dioxide held in solution, on temperature, and on other factors. When the solution reaches an air-filled cave, a discharge of carbon dioxide may alter the water's ability to hold these minerals in solution, causing its solutes to precipitate. Over time, which may span tens of thousands of years, the accumulation of these precipitates may form speleothems.

None of the minerals are very hard.

[Geezer]

It's not one of them thangs that results from lightning strikes perchance?

(I'm anticipating another long lecture.)

[RD]

its very hard,i cant scratch it with a knife...

It's not hard enough to have retained the glossy finish on the rim of the button/cup/crater.

[Bailey (OP)]

yes i did..but your point is..??

Bear in mind Bailey also posted this speleothem ...
http://www.thenakedscientists.com/forum/index.php?topic=27121.msg286936#msg286936 [nofollow]

 [ Invalid Attachment ]
http://books.google.co.uk/books?id=CxwDSfpMq2oC&printsec=frontcover&dq=Beneath+the+surface:+a+natural+history+of+Australian+caves&cd=1#v=onepage&q=stalagmite&f=false [nofollow]



 [ Invalid Attachment ]
http://www.thenakedscientists.com/forum/index.php?topic=29207.msg303322#msg303322 [nofollow]

[RD]

yes i did..but your point is..??

Bear in mind Bailey also posted this speleothem ...
http://www.thenakedscientists.com/forum/index.php?topic=27121.msg286936#msg286936

My point being that speleothem exists in your area.
Jimbob has excluded the possibility this is also speleothem on the basis you have described it as "hard",
but parts of the glossy ("waxy") surface seem to have been worn off after its time in the river.
If it was really hard I think it would have retained the gloss.

[Bailey (OP)]

ok..i found the other rock near katherine in the northern territory,and this one was found near lake argyle in western australia,i dont think think this is a speleothem. []

[JimBob]

It's not one of them thangs that results from lightning strikes perchance?

(I'm anticipating another long lecture.)

Good question! How did you come up with it? Oh! of course, you asked Mrs. Geezre to help. I KNEW you couldn't have done it.

RE: Question from Mrs. Geezer

You asked about fulgurites. I am sorry. No cookie, no banana and go to bed without your dinner.

All of the lightning-strike-fused rocks I have heard of are hollow. The energy of the lightning pushes the unconsolidated material out of the path of the lightning, fusing material at the edge of the energy and leaving a rough surface on the outside.

Gosh, I was hoping I could make an old man's day but Nothing can be as exciting as your spotted dick (with lemon sauce.)

 

[Bailey (OP)]

JB..yes i know lots of things could go wrong if i sent this to you,but,im thinking its worth the risk.if i send it on'secured mail'which is registered and needs an id at the other end..i reckon customs and all those folks should let it through...

[RD]

Bear in mind that even if it is a tektite its retail value is about the same as the cost of posting it from Oz to USA ... http://spacerocksuk.com/tektites.html

I'd suggest you try emailing pictures to an Auzzie geology department ... http://www.geologynet.com/ausunis.htm

[Bailey (OP)]

im not remotely interested in its retail value,because im not ever going to sell it.thanks for your suggestions,i might take it the geology department at cdu(charles darwin uni).cheers. []ps bear this in mind rd..

[RD]

... i might take it the geology department at cdu(charles darwin uni)

I didn't see that one on the geologynet list of "All Australian University Geology Departments".


I tried searching CDU website for "geology" ...

 [ Invalid Attachment ]
                                                                 http://www.cdu.edu.au/

[JimBob]

Bailey

I have been hard at work scouring the literature for all of the known impact sites in the Northern Territory and Western Australia.

I have compiled a list - er well, ah, hummm,  - found a list, more like - of all the know meteorite impacts on Australia. And from one of the most unexpected sources. Probably one of the most well-rounded Professor of geology with and outstanding web site , Steven Dutch at Uni. Wisconsin, Green Bay. http://www.uwgb.edu/dutchs/planets/impact1.htm

IMPACTS

Western Australia


Connolly Basin Western Australia, Australia
    Lat. -23.53; Long: 124.75; Diam. (km): 9; Age (My): 60 ±

Dalgaranga Western Australia, Australia
    Lat. -27.75; Long: 117.08; Diam. (km):0.021; Age (My): 0.03 ±

Goat Paddock Western Australia, Australia
    Lat. -18.33; Long: 126.67; Diam. (km): 5.1; Age (My): 50 ±

Spider Western Australia, Australia
    Lat. -16.73; Long: 126.08; Diam. (km): 13 Age (My): 570 ±

Teague Western Australia, Australia
    Lat. -25.87; Long: 120.88; Diam. (km): 30 Age (My): 1685 ± 5

Veevers Western Australia, Australia
    Lat. -22.97; Long: 125.37; Diam. (km): 0.08; Age (My): 1 ±

Wolf Creek Western Australia, Australia
    Lat. -19.30; Long: 127.77; Diam. (km):0.875; Age (My): 0.3 ±


Northern Territory

Boxhole Northern Territory, Australia
    Lat. -22.62; Long: 135.20; Diam. (km): 0.17; Age (My): 0.03 ±

Gosses Bluff Northern Territory, Australia
    Lat. -23.83; Long: 132.32; Diam. (km): 22; Age (My):142.5 ± 0.5

Henbury Northern Territory, Australia
    Lat. -24.58; Long: 133.15; Diam. (km):0.157; Age (My): 0.01 +/

Kelly West Northern Territory, Australia
    Lat. -19.93; Long: 133.95; Diam. (km): 10; Age (My): 550 ±

Liverpool Northern Territory, Australia
    Lat. -12.40; Long: 134.05; Diam. (km): 1.6; Age (My): 150 ± 70

Strangways Northern Territory, Australia
    Lat. -15.20; Long: 133.58; Diam. (km): 25; Age (My): 470 ±


And the closest - 75 miles south-south west of Lake Argyle

Piccaninny Western Australia, Australia - Purnululu National Park
    Lat. -17.53; Long: 128.42; Diam. (km): 7; Age (My): 360 ±


This one could easily have produced this rock. It would be country rock flung out of the impact and semi-formed in the air. It didn't turn completely to glass.

[RD]

Tektite map, (high concentration in Oz) ...

 [ Invalid Attachment ]

http://spacerocksuk.com/TektitesInfo.html


(I still don't think it is a tektite )

[Bailey (OP)]

JB..thanks heaps for your replies it does sound like i'm in the ballpark for it to be a tectite from the lake argyle area..
RD..you are still thinking it is a speleothem?..mm i think i'll take the geologist's view more seriously,but it it's always interesting to hear other peoples theories too.as for there being no geology department at CDU,i guess i didnt do my homework on that,but i do know a geologist there who works in the horticulture dept.or at least did a year or two ago.thanks for your input too rd.