Uranium oxidation state and related variations in geochemistry of phosphorites from the Negev (southern Israel)

Soudry, David; Ehrlich, Sarah; Yoffe, Olga; Nathan, Y.

doi:10.1016/s0009-2541(02)00144-4

Cited by 42 publications

(25 citation statements)

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“…Re-incorporation in the crandallite lattice by isomorphic substitution of Ca 2þ is one of the mechanism of this enrichment (Bonnot-Courtois and Flicoteaux, 1989). The main uranium compounds in phosphorites are U 4þ and U 6þ (Altschuler et al, 1958;Soudry et al, 2002). The tetravalent form replaces partially Ca 2þ in apatite because of their similar ionic radius of 0.97 and 0.99 A A.…”

Section: Discussionmentioning

confidence: 99%

Distribution patterns of rare-earth elements and uranium in tertiary sedimentary phosphorites of Hahotoé–Kpogamé, Togo

Gnandi

Tobschall

2003

Journal of African Earth Sciences

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Section: Discussionmentioning

confidence: 99%

Distribution patterns of rare-earth elements and uranium in tertiary sedimentary phosphorites of Hahotoé–Kpogamé, Togo

Gnandi

Tobschall

2003

Journal of African Earth Sciences

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“…REE concentration in the Turkish samples (27.4 lg/g) is even much lower than that of the recycled Israeli phosphorites (126 lg/g; Soudry et al 2002) which are themselves quite REE-depleted by comparison to ''average'' phosphorite (461 lg/g;Altschuler 1980). The mean REE/P 2 O 5 ratio in the Israeli phosphorites is 5.3 whereas it is only 1.1 in the Turkish samples.…”

Section: Discussionmentioning

confidence: 75%

“…The chemistry of all these recycled phosphorites therefore reflects the superimposed effect of multistage phosphatization in diagenetic bottom sediments (e.g., Jarvis 1992; Hiatt and Budd 2003;Soudry et al (2008). As in the Negev (e.g., Soudry et al 2002), the recycled Semikan West Kasrık phosphorites typically occur in highly condensed sediment sections found in high structures (Mardin-Derik anticline). Similarly to the Negev also, the fully developed basinward sections of the Kasrik section are represented by bituminous, marly phosphorites of less economic interest.…”

Section: Discussionmentioning

confidence: 99%

“…On the basis of sediment characteristics, and chemical and mineralogical compositions Soudry and Nathan (2001) and Soudry et al (2002) recognized two phosphorite facies in the Negev phosphorites featuring two distinct stages in phosphogenesis: (1) a pristine, laminated, (microbially generated) phosphorite facies, more preserved in basinal sections; and (2) a recycled (reworked) phosphorite facies, predominant in condensed sections near the Negev structural highs and composing most of the economic phosphate rocks. The occurrence of these facies is not limited to Israel; the economic Semikan West Kasrık phosphorites are a good example of economic phosphorites which clearly belong to the recycled facies.…”

Section: Discussionmentioning

confidence: 99%

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Geochemical, mineralogical and isotopic signatures of the Semikan, West Kasrık “Turkish” phosphorites from the Derik–Mazıdağı–Mardin area, SE Anatolia

Imamoglu

Nathan

Çoban

et al. 2008

Int J Earth Sci (Geol Rundsch)

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The geochemistry and mineralogy of a condensed section, *6 m thick of the West Kasrik member (Coniacian-Santonian) near the uplifted northern flank of the Mardin-Derik anticline (south-eastern Turkey) was studied. The only deposit exploited in Turkey is found in this area. The sediment textures as well as the mineralogical and the geochemical results collectively suggest that these recycled phosphorites accumulated in areas of intensive very early diagenesis of the sediments in highly oxic bottom waters, and almost no detrital apport. The total concentration of redox-sensitive trace metals is very low (\600 lg/g); in addition the structural CO 2 and F/P 2 O 5 are unusually high (*5 wt % and 0.14, respectively). REE distribution shows a clear ''seawater'' pattern with a strongly negative Ce-anomaly (0.20 ± 0.02) and heavy REE enrichment (Lu N /La N = 1.50 ± 0.12), however their total concentration is very low. The low REE contents, quite unexpected in recycled phosphorites, are explained by the scarcity of terrigenous components which leads to minimal incorporation of REEs from detrital clastic phases in the CFA fraction. Weathering previously suggested as responsible for the high P enrichment of the Mazidagi phosphorites is rather improbable in the samples we studied, in view of their high structural CO 2 , high F/P 2 O 5 , high (La/Nd) N and (La/Sm) N ratios, and high Sr/P and Ca/P of separated CFA fractions that all negate post-depositional weathering. More likely, the high P enrichment of some rocks (P 2 O 5 content reaches 34%) was produced by sedimentary and early diagenetic processes acting in oxygenated areas of starved sedimentation on and around tectonic highs.

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“…Trace element contents of phosphorites, such as Sr, U, and rare earth elements (REE), vary from one deposit to another (McKelvey, 1950;Gulbdransen, 1966;Altschuler et al, 1967;Tooms and Summerhayes, 1968;Bliskovsky et al, 1969;Sassi, 1974;Altschuler, 1980;Béji Sassi, 1984;Tlig et al, 1987;Fleet et al, 1997;Soudry et al, 2002). According to these authors, the observed variations are related to: (i) the availability of trace elements in sea water and/or interstitial water in the sedimentary basins (Tooms et al, 1969); and (ii) the cationic substitution capacity of apatite (Sin'Kova et al, 1968;Tooms et al, 1969;Price and Calvert, 1978;Altschuler, Therefore, our present study focuses on the mineralogical-petrological characteristics of these phosphorites, their associated trace element and REE distribution, which provide invaluable insights to the reconstruction of phosphate genesis and paleoenvironment.…”

Section: Introductionmentioning

confidence: 99%

Geochemistry and mineralogy of Paleocene-Eocene Oum El Khecheb phosphorites (Gafsa-Metlaoui Basin) Tunisia

Galfati

Sassi²,

Zaier³

et al. 2010

Geochem. J.

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Upper Paleocene to Lower Eocene phosphates of the Jebel Oum El Khecheb profile (Gafsa-Metlaoui Basin GMB, Tunisia) are mostly composed of brown phospharenites lithified or not, granular, with pellets, coproliths, bone clasts and fish teeth. The matrix in analyzed samples is reduced and constituted of various clay minerals (dominantly smectites, palygorskite, sepiolite and rare kaolinite), opal-CT and carbonates. Clinoptilolite is recognized along the series; very few amounts of quartz and feldspar grains are sparsely present. The phosphate mineral is a carbonate-fluorapatite (CFA) sulphated, sodic enriched in strontium and rare earth elements (REE). Statistical analyses of mineralogical and geochemical data highlight the associated elements in the main mineral lattice. In the CFA, the group is composed of CaO-P 2 O 5 -Na 2 O-SO 3 -F-Sr-Th-REE-U-Ba-Zr-Cr. In the silicates, the group contains SiO 2 -Al 2 O 3 -Fe 2 O 3 -MgO-K 2 O-Na 2 O-TiO 2 -Co-Cs-Rb-Sc-Ta-Sb-Mo-As and Cu. Sulphides are represented by Zn and Cd; iron oxides by mainly Fe and Ni. Dolomite and gypsum are present; SO 3 is contained in the latter, but CFA may also have some of this radical in its structure. The Upper Continental Crust (UCC) normalized REE patterns present a variably negative Ce-anomaly, suggesting that the imprint of the marine genesis environment is very well-preserved in the main phosphatic units. Positive-Eu and negativeSm anomalies were detected in some samples. The fractionation of light-REE to heavy-REE, represented by the La/Yb ratio of untreated values varies between 8.28 and 12.94, somewhat less than UCC value (13.64). Enrichment of HREE is due to phosphates. Both ratios reflect the marine genesis environment wherein the formation of the CFA took place in a confined and oxygen poor environment. Then the CFA removed the REE and the trace elements present from the interstitial waters, as was proposed for the various phosphatic basins of Tunisia.

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Uranium oxidation state and related variations in geochemistry of phosphorites from the Negev (southern Israel)

Cited by 42 publications

References 41 publications

Distribution patterns of rare-earth elements and uranium in tertiary sedimentary phosphorites of Hahotoé–Kpogamé, Togo

Distribution patterns of rare-earth elements and uranium in tertiary sedimentary phosphorites of Hahotoé–Kpogamé, Togo

Geochemical, mineralogical and isotopic signatures of the Semikan, West Kasrık “Turkish” phosphorites from the Derik–Mazıdağı–Mardin area, SE Anatolia

Geochemistry and mineralogy of Paleocene-Eocene Oum El Khecheb phosphorites (Gafsa-Metlaoui Basin) Tunisia

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