Jump to content
Nugget Shooter Forums

14.15kg meteorite or wrong. Help please.


Recommended Posts

Hello there, I recently found, whilst walking the dog, a weathered rock that just didn’t fit right in the countryside. In the county of Cambridgeshire, UK there are no ingeous rocks, only peat, clay and sand & gravel underneath. It had been hit many times by the plough and recently lots too but was obviously very hard and had suffered very little from it. I realised a farmer must have thrown it out of the field and it hadn’t landed where I had found it. It seemed to have once had a crust that had been over it, some still remains but light in colour and there was obvious small rust spots here and there. It sparked my interest and when I returned a few days later I took two magnets. The rare earth magnet stuck on but the old type did not, I also used a handheld metal detector on it which did not trigger.

I took it home and weighed it at 14.15kg, I then worked out it’s volume at 4400cc which gave me a density of 3.215. , looking at density charts my interest was really piqued. I then filed a corner with a white card and it left a light sandy colour on the card from the outside filings and a light grey from inside the rock.. On visual inspection I can see very small sparkly flakes with the naked eye and when I used a jewellers loop I can see lots of tiny metal blobs and flakes spread throughout the filed off area and can actually see then all over the ? When I look through a small handheld microscope I can see scratch marks in the metal flakes from the file.

As it would have impacted a clay hillside I think it is the reason it has stayed in one piece. Very close to where it was found is a strange gorge in the clay hillside which unusually has no water action in the bottom of it. I do believe this could have had the potential to have caused it.

I ask for advise as to who too approach for chemical analysis and possible verification, if it is what I am now convinced it is, either an LL Chondrite or I do honestly believe it could be a Carboniferous Chondrite. I base this on the density test but mainly the size and distribution of the metal chondrules I believe I am seeing using the loop. I am new to this so it topic so all is based on what I gleaned from various websites on testing meteorites, I have ordered a Nickel test but understand it may not show positive with these types of Meteorite.

Any help and advice would be gratefully received as I think I may be becoming obsessed with it, even the dogs fed up with me gazing at it.

If you’ve read to the end of this ramble thank you but if you can help thanks even more.

 

Simon 

BFA3D627-941B-4E33-B6C2-EF7725DD847B.jpeg

51047D57-946F-4B65-B8BA-458AAA8984F9.jpeg

F9FE9B4C-E2EA-49CD-A3E3-C043CE40BD4E.jpeg

Link to post
Share on other sites

Simon,

It doesn't have the look of a meteorite, but if it truly has metal flecks in it that would be significant. The slight magnetic content it typical of terrestrial rocks everywhere, even Great Britain. You can take a neodymium magnet and drop it anywhere into sand and dirt and it will be covered in magnetic filings. Try it. The standard source of many out-of-place rocks where I had lived in northern Ohio and also in Great Britain, is the product of glaciation. That said, the possibility of metal flecks that are not mistakenly quartz glistening would indicate that you should get a more professional opinion.

Keep us posted.

billpeters

  • Like 1
  • Thanks 1
Link to post
Share on other sites

Thank you for the responses. Au Seeker, you must have telepathically sent that to me because that was exactly what I was doing. What a difficult task it is photographing them as getting the lighting right, it's very overcast here at the moment.
 

33872AC8-664C-4B7C-818E-E5E080A4BDB2.jpeg

C5B2B678-C5C3-448B-974A-63E14E67CCCC.jpeg

Link to post
Share on other sites

They are pretty tiny. Difficult to tell if that is iron or not. Splash some hydrogen peroxide on it and let it dry. See if they rust.

Try to make sure that it is the little flecks that rust and not the matrix. It is easy to misinterpret observations sometimes. The matrix can be the source of oxidation but it can stain the flecks. So use a magnifier and do several spots one drop at a time until you are satisfied you know where the rust is coming from.

If the specimen is magnetic it has iron in it. Your only job is to determine what state that iron is in. If those are truly flecks of unoxidized iron then you have a rock that warrants further investigation.

It does not look like a meteorite at all. But the flakes don't look like the usual suspects. So use a bit of oxidizer and see if you can get them to rust.

The matrix looks rich in iron oxides. What color was the slurry or cuttings?

I see clear tool marks on the cut. What type of tool did you use to cut or grind the surface?

  • Like 1
  • Thanks 1
Link to post
Share on other sites

Thanks for the response Bob. I happen to have some hydrogen peroxide at home somewhere so I will give that a try when I get back. It certainly makes sense.

Something I hadn’t mentioned before because I thought it maybe wishful thinking, is that you can see lines in bands running around the outside, however as others have now pointed it out to me I now am sure I am not delusional. If it came in to the atmosphere without tumbling the objects  natural aerodynamics would match the orientation of the lines. They are also very hard too photo and is more obvious too the eye and finger tips. Once it stops raining here and better light eventually appears I shall try again. I can’t get the depth of field needed as my phone camera and LED lighting makes it look very flat, 

Its a very heavily weathered rock and has been struck very many times, most recently I believe by a power harrow which is why the farmer ejected it from his field. I used first a belt grinder then a smooth white foot file. The picture is off the foot file card I used. You can see the sandy colour on the left comes from rubbing the weathered exterior but the grey on the right is from the interior.

Thanks again for the peroxide Idea.

3625B6A6-839C-4947-B9B9-E5535D22AB41.jpeg

Link to post
Share on other sites

By the streak I would say that it is magnetite in the matrix that is attracting the magnet. A meteorite does not yield a colored streak.

 The streak is definitely hues of grey. That coupled with magnetism is indicative of mineral iron. Iron in mineralized form rules out a meteorite.

But don't stop doing tests. Every one is a learning experience and will help identify suspect stones in the future.

You are a good observer and are doing what it takes to make a determination. I am impressed!

A successful met hunter is one that can accept failure over and over and maintain objectivity. Many times it is not the successful ID of a space rock that separates the real meteorite hunters. It is being able to be objective about the facts even though it means you were wrong.

In life I never have to admit I am wrong or on the ignorant side of a disagreement. I can just stick my fingers in my ears and pretend. But with rocks you have to keep it real. You just can't lie to them or turn them into something they are not. 

Most people who find a meteorite have had to deal with the cold hard facts of life tens of thousands of times before they get it right. Some NEVER find what they are after. 

Guys like me get really good at proving what they find is not a meteorite. That is a highly refined skill. Finding one is still nothing more than blind luck even if you are the best meteor-wrong expert in the galaxy.

So there are my unsolicited philosophical statements on the trials and tribulations of meteorite hunting. And the identification and subsequent inevitable depression of terrestrial iron.

The best of luck my friend! 

 

Edited by Bedrock Bob
Freaking spell checking editor. You gotta love that shite que no?
  • Like 2
Link to post
Share on other sites

Cheers for that Bob. Strangely when I do the streak test with a ceramic tile is doesn’t leave a steak. That’s why I thought to use one of the white file cards to gather enough material on it.

i can’t get my head around how it has a crust, left in parts but obviously surrounded it once, that seems to have the same consistency as the rock underneath?

I have used the hydrogen peroxide on it for a couple of hours now and it has had an effect I didn’t expect. The small flakes that were just visible with naked eye have vanished, using the loop too. However the  tiny spherical / droplet shaped metallic looking balls, that I assumed the flakes were made from, remain unaffected, They look to me like tiny solder splatters under the microscope and the actual matrix of whatever mineral in between seems unaffected. I cannot photo them yet but should be able too soon.

It’s still a mystery to me Bob. I used to work for a local Sand and Gravel company and regularly would look over the waste pile. Found Mammoth teeth and very large flints but never anything like that. I thought it might be Gabbro, Gneiss or Quartzite to start with brought down by the ice age but as we live within 40 miles of where the ice stopped its southerly migration we just don’t get rocks like that in the clay or round here at all. I ruled them out as they don’t look like this. The find site is right on the edge of the Cambridgeshire peat Fen as the clay rises out. It could only have got here after the last ice age and I certainly can’t see anyone carrying to the site, it’s far  too remote, no waterway, no cart track and with no local buildings made with anything like. The only rocks ever used here for buildings are Oolitic Limestone from Barnack in the next county. I ask myself, why would any one bring that to the area only to leave it in a field to ruin his plough and leave it there. It must have been brought up by modern machinery whose operators are less likely to notice it, until the power Harrow was invented that is.
There is a lot more to this here rock than meets the eye and, if it is of terrestrial origins I still want to know, what it is, where from and how on earth it got here in the Cambridgeshire Fen.

Cheers

 

 

Link to post
Share on other sites

Hello again, I have to ask a question for Bob, did you mean that all Meteorites don't contain magnetite when you said they don't contain mineral Iron. If so it seems to contradict what I have read on other sites, for example here http://meteorites.wustl.edu/id/quartz.htm. also on the site where I found the image below which I must say looks very close to what I am seeing under my handheld microscope.  Before I had seen any Photos of CK Chondrites I had come to the conclusion that if it is a Stony Meteorite then it could possibly be one of those based on the size and distribution of what I am seeing, even though I am well aware of the infinitesimally small chances. I then looked at photos of CKs was pleased to see they look similar. Interesting to me, the fillings would certainly be a light grey colour. I have read through every scrap of info on the above linked site about meteorwrongs and to be honest it has helped to convince me this may be something. I have trawled many terrestrial rock id sites and again have come away more convinced. This will gnaw away at me so I am going to send a sample to a GeoChemistry Lab. Hopefully it may go to the Earth Science dept at Cambridge University. They are the most local to me apparently and as I am writing this they have just made enquiries about it, fingers crossed they will want to look at it closer.

I have never looked for a meteorite in my life and have just stumbled upon this. As such I have no hopes to be dashed especially as the crash course in Geology and Meteorites has been well worth it, however the curiosity in me demands an answer. Your communities hobby is a fascinating one and I do admit it would be nice to be able to add to the knowledge base of it, rite or wrong.

.

image.pngimage.png

  • Like 2
Link to post
Share on other sites

A meteorite does not contain mineral iron in quantities that would make it magnetic. So if a magnet sticks to a rock and the source of the magnetism is identified as magnetite it is not a meteorite.

Free metallic iron and nickel make meteorites stick to a magnet. Hematite and magnetite are what attracts a magnet to a terrestrial stone.

Differentiation in the field is as easy as determining the form of iron that is attracting your magnet.

There are exceptions to every rule I suppose. And in a laboratory under a microscope all sorts of things are observed in meteorites. But in the field with a magnet and streak plate you are going to be able to determine the source of magnetism. And if the source of magnetism is mineral iron you have a terrestrial stone. If the source of the magnetism is free metallic iron you have more testing to do to rule out the possibility of a meteorite.

  • Like 1
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...