Large chondrite like boulder with open vein of impact melt?

Corning, CA(Zone 8a)

This boulder is found with 2 other smaller ones in the pasture where no other boulders or big rocks occur. We are located in Bella Vista, Shasta County California.

The boulder has strange "worm hole-like burrow or vein" on the side. There are some indications of bubble or hole like formations in the entire boulder indicating that at one time it was very hot.... At first i thought the burrow was from a miner or someone taking a core sample... but its not made by man as far as I can tell. Why?
The inside texture of the worm hole like burrow has small bubbles and a crust like appearance showing that it was hot... and as if something went thought the rock when it was hot.
The entire rock has some bubble like and chondrite like formations.
Theory 1
1. Perhaps the worm like burrow is a fossil hole location from a plant or tree or mollusk or sea creature of some kind. There are sea creature and mollusk like fossils found in the smaller rocks in the area near the creek bed.
I donít percieve that its made by a tree or fossil since it shows the numerous hot bubble formations in the cavity of the " worm burrow" like formation.
Theory 2
Perhaps its created by a impact melt as you see in this image of
http://meteorites.wustl.edu/id/oc_HaDL036_4508.jpg
"Sawn face of Harper Dry Lake 036 (L6; find, 2010, CA). This meteorite shows dark veins of impact melt, a feature sometimes seen in ordinary chondrites.
chondrite meteorite
Look forward to any other theories, questions and comments on this.


This message was edited Sep 25, 2011 10:12 AM

Thumbnail by leeannconner
Corning, CA(Zone 8a)

Here is a close up of the hole towards the bottom... you can see the small bubbles in the cavity.

Thumbnail by leeannconner
Corning, CA(Zone 8a)

this shows the size of the boulder.

Thumbnail by leeannconner
Corning, CA(Zone 8a)

this shows the size and length of the exposed "burrow"

Thumbnail by leeannconner
Calgary, AB(Zone 3b)

Can you identify what kind of rock it is? Trace fossils such as worm burrows and tree roots are very common but occur in sedimentary rocks. Your rock doesn't strike me, from the photo, as being a sedimentary rock, but if you said it was sandstone, burrows would be possible. They are usually filled by sediment (though the disruption of bedding/grain makes them visible) though the fill can erode out with exposure.

Corning, CA(Zone 8a)

the inner crust of the burrow looks to be glassy basalt from what i have seen online i am just learning all the terms.
the rock it self i cannot seem to identify but when i looked close it has metal specks and looks to be basalt like... not sure though.

http://www.pitt.edu/~cejones/GeoImages/2IgneousRocks/IgneousCompositions/3Basalt.html

does not seem to be sandstone.

i just got in from taking new picts outside closeups of the hole and bubbles that are different showing somthing hot pierced through it...and picts of all three of the boulders as they appear.. one is the top that is about 25 foot away . be back shortly with more picts. of it.

Corning, CA(Zone 8a)

here is a close up of the hole

Thumbnail by leeannconner
Corning, CA(Zone 8a)

this gives you an idea of what kind of rock this is... it has holes in it like you find with lava rock.. but less of them.

Thumbnail by leeannconner
Corning, CA(Zone 8a)

do you think it might be possible that this is a lightening strike on this rock which is what spit it in 3? especially due to the high iron or metal content... ? possibly that would explain the hot look about it ie bubbles....?

Corning, CA(Zone 8a)

here is another shot of the big boulder.. might be volcanic basalt? there is rust like formation on this piece i chipped off.. it is not sandstone.. the piece is sharp and can cut like iron or metal.. and heavy but breakable.

Thumbnail by leeannconner
Calgary, AB(Zone 3b)

You may want to investigate the terms "vesicle"/"vesicular basalt"... gases escape as the magma cools, leaving small cavities and, even, small (or quite large) tubes.

Corning, CA(Zone 8a)

http://www.sott.net/articles/show/148077-Chunk-of-meteorite-leaves-small-hole-in-Bourges-France


In this picture you see that this meteorite hole looks like a large version of what is in the rock here... do you think so? i did a little search on vesicular basalt and indeed this does look to be something of the sorts and it also looks like something they use in iron ore...

i have yet to grind and look at this and see if magnetic or if it has crystals as well.

it seems to have a few crusts of iron and some specks of metal and chrondule like formations.. sort of... that is why its still interesting to me... and the burrow hole too.

when i can look at it under scope will report back. thanks for all the good info.

Calgary, AB(Zone 3b)

No, I think the odds of finding a bunch of meteorites under the circumstances you mention are very, very, very slim... However, the odds of seeing vesicles in an igneous rock, in an area with the geologic history of your area, is high.
Basically, to start with the assumption that you have found a bunch of meteorites, and then trying to find bits of evidence to fit that assumption, while passing over the gross characteristics of the samples, is really not a supportable way of identifying rocks (sorry to say). Would there happen to be a college or other institution that has a geology department in your area, that you could take the rocks to, or send photos to, for an expert opinion?

Corning, CA(Zone 8a)

altagardener, Thanks for honest opinion... I dont think that I found a bunch of meteorites, but perhaps im on the trail of a few. Please keep in mind that i am not randomly looking in a spot and trying to fit my specimens into meteorites categories.... I am looking in an area of concentration,where hundreds if not thousands of years of accumulating meteorites might drain....I am looking at the websites where they give examples and how to identify, but as you know you can only go so far this way. I have to learn more and do better tests. I am also very interested in finding out about the magnetism in the crystals and what kind of metals these are in the rocks. I do plan on submitting a few samples to the local Shasta College, but I want to narrow things down and learn more about them before taking their time. I do agree....... it will be time in near future after further inspections and getting snapshots with a digital microscope rather than gross images...and discussions. thanks again.

Corning, CA(Zone 8a)

In 1876 a large meteorite hit in our county..not too far away... it was 4 foot in diameter. The boulder in this picture that i have posted, appears next to a 300 year old oak tree... my boulder is only 3 foot in diameter though. Perhaps it could be related to the same event.. yeah i know more than 1 zillion and 1 chance....... but it does show some interesting characteristics.

I am sure alot of meteorites have been over looked because we are near active volcanos...etc...
and why not over the thousands and thousands of years these meteorites could collect in the creek?
We have witnessed spectacular showers over the eastern skys towards lassen in our area.. and some of them, almost as if exploding right over the top of us...

If one knew what they were looking for perhaps it would be a good way to go about finding them.

Meteorite hits in our area.

1876
http://blogs.redding.com/dsmith/archives/2010/11/the-day-a-meteo.html

2009- might be space junk?
http://www.redding.com/news/2009/mar/12/unidentified-object-from-sky-destroys-car-in/
http://www.redding.com/photos/2009/mar/11/29418/

Calgary, AB(Zone 3b)

Quote from leeannconner :
This boulder is found with 2 other smaller ones in the pasture where no other boulders or big rocks occur. We are located in Bella Vista, Shasta County California.
This message was edited Sep 25, 2011 10:12 AM


Something to consider as a possibility, given your location and the geologic history, is the possibility that it's a volcanic bomb.

Corning, CA(Zone 8a)



anorthosites can be important sources of magnetic anomalies

http://www.sciencedaily.com/releases/2008/02/080217093611.htm

Is there any possibility its an anorthsite? I would suppose it could be a volcanic bomb... i will keep this in mind and do more research on this.....meanwhile. i wan to explore more.

Calgary, AB(Zone 3b)

It may also be a glacial erratic (which says nothing at all about the actual composition of the rock... )

Calgary, AB(Zone 3b)

Anorthosite is, categorically, a coarse-grained rock, which yours isn't.
Rock type is determined, at the highest level, on a judgement of whether it is sedimentary, igneous or metamorphic. (This is the place to start - not whether it's a meteorite or not, or whether minerals in it have a trace of magnetism.)
Then, if it is igneous or metamorphic (which yours seem to be), you look at the crystal size and the mineral content and the proportions of groups of minerals to classify the rock type. So, you need to be able to recognize common minerals...

Corning, CA(Zone 8a)

Thank you very much altagardener for that concise summary. I will imprint this protocol in my brain.

1. type of rock? metamorphic, igneous or sedimentary ( i will have to understand the distinctions better, this is where i get messed up)
2. mineral content ( will need a scope for this to compare the size shape and general distinctions) i cannot wait for it in the mail any day.
3. once i understand this, then i can better identify these rocks.

I really appreciate it.

Next I will do a try this approach on some interesting rocks that appear to be like marble. Thanks again for taking the time to help me out here.. even though i seem to have a thick skull... you have alot of patience :)

Calgary, AB(Zone 3b)

Quote from leeannconner :

I am sure alot of meteorites have been over looked because we are near active volcanos...etc...
[/quote]
I'm certain that the geology of your state has been studied in great detail, given the occurrence of economic minerals (e.g. gold), and that a great number of maps and publications are available that would attest to that. That's not to say every inch has been examined, of course... but these maps and publications would provide a good starting point for understanding what rock types you can expect to find in your area.

Quote from leeannconner :

and why not over the thousands and thousands of years these meteorites could collect in the creek?

There are creeks and river drainages all over the world, so for your particular creek to offer any advantage towards concentrating meteorite finds, one would have to presuppose that you live in an area that is, for some reason, more prone than anywhere else to meteorite strikes. This is extremely unlikely.

[quote="leeannconner"]
We have witnessed spectacular showers over the eastern skys towards lassen in our area.. and some of them, almost as if exploding right over the top of us...

Yes, we see spectacular meteor showers here too... for example, the annual Perseid meteor showers... but meteorite strikes remain rare events.

None of this says you can't find a meteorite in your area... the fact that you are looking at all increases the chances... but I doubt there is any reason to think you have a greatly better chance there than elsewhere. Good luck and have fun with it, though!


This message was edited Oct 4, 2011 11:20 AM

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