Did I Find A Strewn Field?

[jasong]

Found 4 chondrites over an area of about 5 square miles. I don't know if I was just incredibly lucky or what, since they appear to be quite spread out, but the smallest I found in the first spot I stopped, about 5 minutes after I turned my detector on. Another few hours turned up nothing.

I drove about a mile away and the next largest (with the large stress fracture) turned up as my first target for the area, 10 mins after I turned my detector on, then nothing else for another hour of detecting.

I drove about 2 miles further and yet again, 10 mins after turning the detector on I got the biggest one (it's about the diameter of a quarter, for scale). But this time I managed a 2nd find in the same area, a few hours later.

So, the fall seems to cover quite a large area, but the meteorites were only found where bedrock was at surface so far, which is quite a small part of the whole area. They seem to be quite sparsely spaced out compared to Gold Basin for instance. Does this qualify as a strewn field?

This is in Wyoming, not a common spot for meteorites. Everything was at or near surface, looks to be a kinda fresh fall? I'm sure there are a lot more out there, they were getting bigger going North, so it seems that was the direction of travel. 

[mn90403]

Did you look at the map to see if meteorites have been found and named from the area?

[jasong]

Yes, there are no known meteorite falls anywhere close to this area.

I'm not real connected with the meteorite community though, maybe there are people hunting Wyoming right now? But I haven't heard of any, so figured I'd post this here.

I have to admit I haven't spent a lot of time out there looking for more, but the wide area I found these over seems to indicate to me a fairly large field with more left to find out there. Problem is bedrock is sparse and the ones I found were all on bedrock. 

Just kinda curious what comprises an official "strewn field" and what is just a fall. Also, if I submit these finds to Metbull or whoever tracks these sorts of things, do I get to name it?

[jasong]

I just shot it with the XRF out of curiosity, so I could compare to a Gold Basin. They are similar, but different. 

Here is the XRF results in Mining mode. Keep in mind these aren't taking into account things like Oxygen, which comprise a significant portion of some parts of a meteorite, so they don't add to 100% due to light matrix elements.

Mine seems to be much lower iron than the Gold Basins, also lower nickel. Aluminum, chromium about the same, cobalt and titanium about the same (they are off the screen here, cobalt is questionable in mining mode since that mode is not calibrated for it). Notable is mine seems to be much higher magnesium than the Gold Basins. 

But in all, the composition of elements is basically the same, just slightly different proportions. Here is the Gold Basin from a post I made a long time ago. It cut off at 0.1% threshold so the chart wouldn't be cramped, there were more elements in it.

[Valens Legacy]

Nice finds, sounds like the thing broke up in flight which is normal and fell over the area.

Good luck on your next hunt.

[Hardtimehermit]

Not sure here, they don't look too special in the photo and the lack of nickel is also an issue. If they are true, i would say you found a strewn field, but first have you been able to grind a window to the inside ? I hope you found a new meteorite bro keep us updated, thanks for sharing.  ht

[jasong]

They are definitely chondrites. Some of the chondrules are visible in the fusion crust.

A photo in a bit better light, the first photo was not great. I'm travelling right now and don't have anything to grind with, but these look the same as a Gold Basin for the most part. Just a little newer I think.

 

[GB_Amateur]

13 hours ago, jasong said:

So, the fall seems to cover quite a large area, but the meteorites were only found where bedrock was at surface so far, which is quite a small part of the whole area. They seem to be quite sparsely spaced out compared to Gold Basin for instance. Does this qualify as a strewn field?

This is in Wyoming, not a common spot for meteorites.

Reminds me of the definition of a 'coin spill'.  How many coins in a clump are needed to call it a spill?  (OK, back on topic...)

You found four meteorites in a few (person-)hours.  I don't think it's yet a good comparison with Gold Basin (in terms of size, etc.) where thousands of person-hours have led to all its finds.

I wonder if the on-bedrock correlation has importance (it might...).  Is that a selection effect -- your choice of where to detect?  Is the wind erosion selectively uncovering those and there are more hidden by soil?

The more/less uniform composition (assuming you've X-rayed all four) would indicate to me that they are from the same parent meteoroid.  That alone should indicate you've found a strewn field.

Finally, the reason Wyoming isn't a common spot for meteorites shouldn't be much of a factor, IMO.  (It's also not known for metal detectable gold, and you've shot that commonly held fallacy all to hell.)  Definitely a selection effect in Arizona with all the detectorists (both gold hunters and meteorite hunters).  There's also the dry lake bed correlation which I still don't understand.   Low flora activity likely makes them easier to find, and low rainfall areas mean they last longer?  Besides, there may be an advantage for Wyoming having unknown meteorites:  The low population means recent falls (last couple centuries anyway) are more likely to have gone unnoticed.

Good stuff and I look forward to reading more as you delve deeper.

(BTW, on a related note, are you concenred that revealing the location of your meteorites would lead to competition for your primary goal finds?)

[mn90403]

11 hours ago, jasong said:

Just kinda curious what comprises an official "strewn field" and what is just a fall. Also, if I submit these finds to Metbull or whoever tracks these sorts of things, do I get to name it?

I think 'official' is the key word here.  Where would it be applied?  I've mostly assumed that all of the meteorites listed on the MetBull are just one of many possible.  If you look at that map and you go to a fall then that is a good place to find more.  There could be a strewn field and many more meteorites were found but not reported.

Take Jungo Dry Lake or many of the other dry lakes.  They have named meteorites found on them.  Then other people come along and find more, and some are slightly different names because the composition of their meteorite is different than the first named fall and so on.

I was with Twink one hunt in Franconia, and she found a chondrite and thought it was different.  She submitted it and it was not the same as the other irons and chondrites in the Franconia Strewn Field.  Her meteorite has a different name, and she is listed as the discoverer.  

In order to get her chondrite listed she had to have to exact GPS location.  The official name is based upon that location, but she is the discoverer.

You could suggest a name based upon map names already in existence but it's not like naming a new organism or star!  haha

[jasong]

Yeah this definitely isn't as big or noteworthy as the Gold Basin. Ive detected around the area enough to know basically where it stops and I don't think it's much bigger than 5 square miles, that might be overestimating too.

I was just kinda curious where the line between "strewn field" and simply widely dispersed fractured pieces is drawn. 

If I wasn't prospecting the area currently I'd report it to wherever you report such things. I'd rather not have it as a pin on a map right now though and attract meteorite hunters. Especially if I can't name it after my mom, which I hoped to do. 😄

The bedrock correlation might just be detecting bias.