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Turning Lemons into Limes


DPS Ammonite

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Here are some more Miocene plant fossils from lake sediments north of Phoenix, Arizona. The first large piece of brownish chert, a lemon, had poorly preserved stems. Because the lake sediments had abundant uranium, the rock glowed bright lime green under short wave UV light. Organic matter often attracts uranium deposition.The second piece in the third photo has a great impression of plants that looks like it could have been created in fresh concrete yesterday.

 

Field of view in all photos 6-9cm long.

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My goal is to leave no stone or fossil unturned.   

See my Arizona Paleontology Guide    link  The best single resource for Arizona paleontology anywhere.       

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Very cool. I picked up a handful of similar white chalcedony from my cousin's sandy backyard when I visited Phoenix a few years ago. The green glow under UV light, especially shorter wavelengths, is spectacular. I didn't realize they sometimes contained fossils - I might have to keep an eye out if I ever return! 

Stephen

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Neat fossils, John!

Thanks for showing us. :) 

    Tim    VETERAN SHALE SPLITTER

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"In every walk with nature one receives far more than he seeks."
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Those are really neat! That green glow is surrealistic

So what kind of exposure do you think those little jewels/sediments come with? Some of the stuff down here when they are mining phosphate has similar mineral/minor radioactive content. 

 

Florida

Radioactivity and Phosphatic Clay Ponds

The clay in the ponds came out of the ground as part of the matrix, which naturally contains the radioactive elements uranium and radium. Some of this radioactivity ends up going to the clay ponds.

Phosphatic clay sediment in the ponds have a higher level of radioactivity than sediment in natural lakes, but the water is like other lake water. When the pond settles the soil has higher levels of radioactivity than normal soil.

The average Florida soil has about 2 pCi/g of radioactivity from both uranium and radium. A mineralized soil in an unmined area has about 10 pCi/g of radioactivity. A clay settling area has up to 40 pCi/g of radioactivity. [pCi/g (picocuries/gram), as explained in the segment explaining why phosphogypsum is stacked, is a measurement used to denote the amount of radioactivity per mass or volume of the material in question.]

It sounds like the clay is highly radioactive compared to other Florida soils, but 2 pCi/g represents a very small amount of radioactivity. It is two-trillionth of a curie per gram. At 40 pCi/g the clay is 20 times higher than average Florida soil and four times higher than mineralized soil, but still, it is only forty-trillionth of a curie per gram.

When considering risks associated with radioactivity and the clays, consider a study of typical Florida crops grown on a clay settling area. The study found that if a person ate as much food as he or she could get from the crops grown on this clay settling area for a year, he or she would receive a 3 mrem dose of radiation from the food in addition to the 360 mrem dose of background radiation received naturally every year. [A mrem (millirem), is a measure of radiation dose.]

That amount would be lost in the natural variation in the background dose the person receives in the year. To put it in perspective, a person receives about 5 mrem from cosmic radiation during one roundtrip, transcontinental airline flight.

http://www.fipr.state.fl.us/about-us/phosphate-primer/radioactivity-and-phosphatic-clay-ponds/

 

A couple years ago here locally we had a sinkhole develop beneath a gypsum stack in the Bone Valley area where a myriad of cool vertebrate fossils originate and it released over 200 million gallons of waste water into the Florida aquifer. I often wondered what readings some of the fossils give off. I wonder if any have enough to emit the same colors yours do. They did some serious damage control on this sinkhole incident and have been monitoring Radium amongst other things since. I've not seen anything lately on that particular incident but with our Karst topography here in the state it aint a situation/problem that's going away...

https://www.nature.com/articles/s41598-018-29541-0

Fate and transport of radioactive gypsum stack water entering the Floridan aquifer due to a sinkhole collapse

Daljit Sandhu, Arvind Singh, Steven J. Duranceau, Boo Hyun Nam, Talea Mayo & Dingbao Wang 

Scientific Reportsvolume 8, Article number: 11439 (2018)

 

Be safe! Thanks for showing us the interesting finds! 

Regards, Chris 

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13 minutes ago, Plantguy said:

Those are really neat! That green glow is surrealistic

So what kind of exposure do you think those little jewels/sediments come with? Some of the stuff down here when they are mining phosphate has similar mineral/minor radioactive content. 

A report about uranium favorable areas in Arizona said that the chalcedony was up to four times more radioactive than normal rocks. In other words, no worries. Yellow green fluorescing chalcedony is common in Arizona: better pieces like mine, less so. It takes only a little bit of uranyl molecules to make chalcedony fluoresce.

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My goal is to leave no stone or fossil unturned.   

See my Arizona Paleontology Guide    link  The best single resource for Arizona paleontology anywhere.       

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1 hour ago, Harry Pristis said:

On the other hand,

 

radiation_EPA.JPG.e08794ef1eff02641368b218902b0b2a.JPG

Thanks Harry. Yep its very serious stuff and I forgot completely/failed to mention that dangerous aspect. 

Regards, Chris 

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