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Colorado Prospector - Gem and mineral prospecting and mining forums _ Gem and Mineral Specimen Finds or Processes _ Tiny geodes, new info... Possible fault line..

Posted by: GRenee1980 May 8 2016, 10:25 PM

And the plot thickens. Obsessing over tiny geodes I found near lake/mchenry county il. I'm pretty sure they're Quartz. Found 2 more today, just on surface.
After more web searching, I was reminded about a small earthquake, January 31, 2012. 2.4 mag. Epicenter approx 1 mile from my home. Other sources say little is known about fault lines in n/e il and s/e wis.
I am so curious but completely without resources. I've reached out to the nearest mineral society that seems most legit, but they're 3 hours away near Iowa and so small there is no forum/chat or solid resources.
I'm reaching out to the experts... You guys!!!!

Thoughts? Opinions? Suggestions on how I can find out more?? I have another post about these tiny geodes on surface of cornfield I wrote yesterday with pics included.
Interestingly enough, found another post from someone in Illinois who did was sifting and panning somewhere in my area and found some stones he couldn't identify. I read that chain and made a guess... Spinel/spinel? Drift diamond?

My area is so strange and unresearched. Limestone quarries, lakes, smallish rivers, hills, (these hills start near my home and continue a bit west, but just east it becomes very flat heading back towards Lake Michigan) clay, farms (with fields of divers stones and minerals). We experienced several glaciers.. Thus some sporadic mineral deposits from glaciers. I've read there is a glacial "out wash" nearby in mchenry county. But again, history of earthquakes with really no info.

Ok, I'll stop but I'm obviously obsessed. The lack of info and even documented lack of true knowledge of the local topography due to soil/heavy glacial dirt/debris if you will... Along with knowledge there must be a fault nearby (again very little info and seemingly no follow up). Glaciers, earthquake faults, and tiny geodes... Where to go from here...

Posted by: EMac May 9 2016, 09:00 AM

I got nothin'

Posted by: EMac May 11 2016, 09:52 AM

I feel bad for having nothing, so poked around. https://www.ideals.illinois.edu/bitstream/handle/2142/44511/guidetogeolo93rein.pdf?sequence=2

I like gold, so of course had to check this out: http://www.isgs.illinois.edu/outreach/geology-resources/gold-its-occurrence-illinois

Also found this map from USGS of the mineral industry in Illinois: http://minerals.usgs.gov/minerals/pubs/state/2004/ilstmyb04.pdf

You're right....Colorado is much better for geology :)

Posted by: CP May 11 2016, 10:55 AM

Great answer Emac, I was also going to suggest some USGS resources for this. Good info!

Posted by: GRenee1980 May 12 2016, 08:17 PM

Thank you CP and EMac! I appreciate all of the info!!! Just read the link specific to McHenryCounty, probably going to go explore some glacial out washes. Still no answer on the tiny geodes, couldn't see any reaction but crystals so small/material so little, I cannot see clearly. Hoping to find a larger specimen to test.

I'll update my findings... When I have them, lol.

Best regards and happy hunting!!
GG

Posted by: GRenee1980 May 18 2016, 08:02 PM

Mystery solved!!! Limestone!! Lots of it broken up by years of crops and and erosion and who knows what else. I've found slabs with little embedded geodes! I wonder what's deeper where the stone is probably larger and more dense!!! I'll post pics soon

Posted by: EMac May 19 2016, 09:20 AM

I'm gonna go out on a limb and say....limestone?

Posted by: EMac Jun 16 2016, 01:26 PM

Finding one of these in the limestone would make it pretty sweet!: http://www.coloradoprospector.com/forums/index.php?showtopic=5087

Posted by: fenixsmom Jun 16 2016, 04:32 PM

I'm not an expert by any stretch of the imagination, but do you by chance have fracking in the area? I'm remembering reading something about Oklahoma having more quakes since fracking started. Just a thought.

Posted by: johnnybravo300 Jun 17 2016, 10:01 PM

Limestone is good stuff.

Posted by: johnnybravo300 Jun 17 2016, 10:06 PM

Geodes can form in limestone from any cavity that fills with silica. No volcanism needed.
What do you suspect is in the glacial outwash? I'm just curious.

Back home (Topeka,Ks) they have had earthquakes bad enough to shake their houses. Id never known of any quakes there before. Not good.