I just touched science!

[Faithfree]

Nice widmanstaetten pattern!

A bit of the Gibeon Iron by any chance?

If you're a rock hound:-

rock sample 3.JPG

Shadow at the bottom is an artifact from the camera flash.

Looks like a vein of intrusive igneous rock (bottom) in contact with a fine grained contact-metamorphosed rock.

[colubridae]

Nice widmanstaetten pattern!

A bit of the Gibeon Iron by any chance?

If you're a rock hound:-

The attachment rock sample 3.JPG is no longer available

Shadow at the bottom is an artifact from the camera flash.

Looks like a vein of intrusive igneous rock (bottom) in contact with a fine grained contact-metamorphosed rock.

Nice work. I could not have done that over the web.

Sample was found in a disused quarry Start Bay south coast of devon.

I have as many theories as I have geology friends. Typical.

Best consensus is it’s an intrusion of basic rock with country rock xenolith.

Problem with that theory (which you can't see very well from the photo) is that the contact is dead straight.
so the country rock broke into the intrusion with a near perfect flat surface.
Sample was not in situ so no further info available.

I've not done chemical analysis of the two sides, but they certainly 'look' like they may be identical in composition. What I need is a thin section and ‘scope.
I’ll ask on the santa thread.

Here is another sample from the same quarry

Grain size much larger on this sample.

[normal]

How gneiss for you!

[colubridae]

How gneiss for you!

nice try

but gneiss has 'banding' in the crystal orientations.

Those crystals are random; so straigthforward crytsallisation from melt. (or poss. from aqueous solution).

[Cunt]

Found out I was wrong about some stuff, Mark set me straight last night.

First, Mark didn't discover the Acasta Gneiss outcrop, but instead was working in a remote camp where he discovered the info. A local prospector named Walt previously held the claim and when it ran out for him, Mark filed and now holds the claim.

From the Globe article... (no, not THAT 'Globe' lol)

“I don’t know why they haven’t protected it,” said Walt Humphries, another Yellowknife prospector who sold enough of the gneiss to fill a refrigerator.

About Mark...(from the same article)

Mr. Brown has a Grade 11 education, lives in a 7.5-square-metre shack without electricity or running water, charges his cellphone using parking lot block-heater plug-ins and boasts that, if need be, he will trap squirrels for breakfast. He is, he said, a bush man capable of great self-sufficiency, which has already allowed him to invest $15,000 of his own money into the Rock of Ages project. And this is just the start. He plans to discuss a marketing strategy with a communications firm Monday.

I now have (photos later) a chunk of this rock for myself, and the opportunity to support Mark's business and help him get it rolling. I am not too sure as I am just absorbing the new information. I will let you all know as soon as I know.

(by the way, there is a site up and running where one can order a piece of the Acasta Gneiss, but I would suggest reading the Globe article thoroughly first)

[Faithfree]

Found out I was wrong about some stuff, Mark set me straight last night.

First, Mark didn't discover the Acasta Gneiss outcrop, but instead was working in a remote camp where he discovered the info. A local prospector named Walt previously held the claim and when it ran out for him, Mark filed and now holds the claim.

From the Globe article... (no, not THAT 'Globe' lol)

“I don’t know why they haven’t protected it,” said Walt Humphries, another Yellowknife prospector who sold enough of the gneiss to fill a refrigerator.

About Mark...(from the same article)

Mr. Brown has a Grade 11 education, lives in a 7.5-square-metre shack without electricity or running water, charges his cellphone using parking lot block-heater plug-ins and boasts that, if need be, he will trap squirrels for breakfast. He is, he said, a bush man capable of great self-sufficiency, which has already allowed him to invest $15,000 of his own money into the Rock of Ages project. And this is just the start. He plans to discuss a marketing strategy with a communications firm Monday.

I now have (photos later) a chunk of this rock for myself, and the opportunity to support Mark's business and help him get it rolling. I am not too sure as I am just absorbing the new information. I will let you all know as soon as I know.

(by the way, there is a site up and running where one can order a piece of the Acasta Gneiss, but I would suggest reading the Globe article thoroughly first)

From the scientific paper I linked to earlier, the outcrops of Acasta Gneiss occur over several hundred square kilometres of area. I assume what the prospector is targeting is the actual outcrop from which the particular oldest dated sample came, and the scientists involved think the site should be preserved for future research - which is fair enough. It would be possible to collect bits of Acasta Gneiss from lots of surrounding areas without disturbing "the" site. The critical thing that is pointed out in the research paper, and the Globe article, is that the Acasta Gneiss includes an intimate mixture of older and somewhat younger layers on quite a small scale. Whether you collected from "the" site or from the surrounding area, you would not be able to conclusively state the age of any single fragment without going through the very expensive and time consuming dating process.

[Cunt]

From the scientific paper I linked to earlier, the outcrops of Acasta Gneiss occur over several hundred square kilometres of area. I assume what the prospector is targeting is the actual outcrop from which the particular oldest dated sample came, and the scientists involved think the site should be preserved for future research - which is fair enough. It would be possible to collect bits of Acasta Gneiss from lots of surrounding areas without disturbing "the" site. The critical thing that is pointed out in the research paper, and the Globe article, is that the Acasta Gneiss includes an intimate mixture of older and somewhat younger layers on quite a small scale. Whether you collected from "the" site or from the surrounding area, you would not be able to conclusively state the age of any single fragment without going through the very expensive and time consuming dating process.

This is why I am hesitant...I may well participate with the fellow, but it will only be if the rock is clearly identified and advertised. I will probably find out tonight. IF he is willing to advertise it for what it is, unambiguously, then okay, if not, then I guess I go back to non-fame

[normal]

How gneiss for you!

Gneiss try

but gneiss has 'banding' in the crystal orientations.

Those crystals are random; so straigthforward crytsallisation from melt. (or poss. from aqueous solution).

[Cunt]

I decided not to help him out personally, but to pass it on to a business acquaintance who will help him out with it. It isn't EXACTLY what I had envisioned. I guess I am too idealistic.

Anyway, the rocks are pretty, the story led me to learn and they will STILL make excellent...er...ammo against young earth claims.

Anyone want to see it?

[Cunt]

Fuck it, I'll show you anyway.

(the coin is a dime)

Can any of you real rockhounds tell me any more about it from this photo?

[Svartalf]

is that gypsum at the top?

[colubridae]

Can't reaaly see very well.

But looks like no matrix, and interlocking crystals. Based on that I would say igneous.

Crystals are less than 2mm. so medium grained.

There is a dark patch and a white patch so the grains are banded?

There also seems to be dark inclusions in some of the crystal grains.

There is a hint of brown, so some iron oxide.

I'm guessing some gneiss?

I could be wildly off


Or maybe quartzite or marble or even limestone
I think that covers my arse enough?

[Svartalf]

actually, I'd have thought a quartz extra rich granitic thing... or again my ignorance of things geological could again have gotten the better of me.

[colubridae]

Yep its a bit difficult to tell.

If it was granitic then the grains would be more or less randomly mixed. But it looks kind of patchy?

[Cunt]

It should be a piece of the Acasta River outcrop (gneiss).

I will try to take 'better' photos of it, but I don't know what you all need for 'better'. Any ideas?