Re: Radioactive Fossils

[DWMCCARN@aol.com]

Hello:
Just a few notes about U concentration mechanisms (and localities) in 
fossils. Hope it helps.
D. McCarn


Summary of Uranium Enrichment in Fossils
Marine (Uptake from Seawater)
1) Phosphorite - Near Shore Marine - Fish bone detritus - Uptake of U from 
sea water into phosphate / apatite, Florida, Morocco,  Kazakhstan - Byproduct 
U from Phosphoric acid for fertilizers; 75-150 PPM U3O8

2) Phosphate nodule - Off Shore marine - Uptake of U from seawater, 
Frequently occurs in black shales - 100 PPM U3O8 

3) Black Shales - Marine shales (Chattanooga Shale, SE USA; Pierre Shale, 
Mid-Continental USA; Kolm Shale, Sweden) 100 PPM U3O8 - Uptake of U in sea 
water - Microfossils

Terrestrial
1) Vertebrate fossils - U replacement of Ca in Apatite; Jurassic Morrison Fm, 
Western USA; 0.25% U3O8 up to low percent range - Also enriched are Rare 
Earths. Apatite	Ca5 (PO4)3 (F,OH,Cl); (U, RE replaces Ca).

2) Uraniferous Lignites - Low grade lignites sometimes associated with U 
deposits (Red Desert, Wyoming) - 100-150 PPM U3O8

3) Highland Moor (Peat Bog) - Small bogs in catchments draining granitic 
highlands (Sangre de Cristo Mountains, Colorado & New Mexico 50-100 PPM U3O8)

4) Organic Fossil - Terrestrial carboniferous material (trees, woody 
material) in spatial association with sandstone U deposits. Mineralized with 
uraninite (reducing) or carnotite (oxidizing - uranyl vanadates) 0.25% U3O8 
up to low percent range. Colorado Plateau, Grant's Mineral Belt, Wyoming, 
Kazakhstan, etc.

Potassium Enrichment
1) Almost all Shales (clays frequently have K in structure)
2) Evaporites - KCl (sylvite in bedded salts) (no fossils, though)

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