@article {043_Tzifas,
	title = {Uranium-bearing phosphatized limestones of \{NW\} Greece},
	journal = {J. Geochem. Explor.},
	volume = {143},
	year = {2014},
	pages = {62 {\textendash} 73},
	abstract = {Abstract Sedimentary Mesozoic rocks from \{NW\} Greece (Epirus region), and particularly laminated phosphatized limestones, bedded chert-rich limestones and brecciated phosphatized limestones, were examined for their actinide content. Gamma-ray measurements using a \{HPGe\} detector showed that the above geological materials exhibit high radioactivity, mainly attributed to the 238U-series. The 238U content (up to 7700\&$\#$xa0;Bq/kg) was determined by the 1001\&$\#$xa0;keV photopeak of 234mPa, the 238U daughter. Bulk geochemical analyses using ICP-OES/MS showed variable U concentrations with a notable value of 648\&$\#$xa0;ppm in the case of dark organic-rich material hosted into the brecciated phosphatized limestones. Relatively high concentrations of Cd, probably related to apatite, were also revealed. On the other hand, the rock is geochemically depleted in \{LILE\} (e.g. Cs, Rb, K), as well as in As, Sb and Se in contrast to {\textquotedblleft}average phosphorite{\textquotedblright}. Powder-XRD combined with optical microscopy, SEM{\textendash}EDS and \{FTIR\} confirmed abundant apatite, besides calcite, as well as organic compounds (organic matter/O.M.) which should be associated to the high U content. According to Th/Sc vs. Zr/Sc discrimination diagrams the organic-rich part of the U-bearing phosphatised limestones exhibits a mafic trend, in contrast to the rest of the studied rocks lying close to typical pelagic sediments. However, Eu/Eu* vs. Ce/Ce* diagrams, in combination with SEM{\textendash}EDS, indicated that the organic-rich part is a typical sedimentary material whereas the organic-poor (and also U-poor) part of the rock is secondary calcite related to surface waters. As far as we know, the studied rocks from \{NW\} Greece are classified as among the richest U-bearing phosphatized limestones and/or sedimentary phosphorites in the world.},
	keywords = {Uranium},
	issn = {0375-6742},
	doi = {10.1016/j.gexplo.2014.03.009},
	author = {I.Tr. Tzifas and Godelitsas, A. and A. Magganas and E. Androulakaki and G. Eleftheriou and Mertzimekis, T. J. and M. Perraki}
}
