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Geological and Mineralogical Analysis of Phosphorites in the Jebel Dhyr Syncline, Eastern Algerian Atlas

Boulemia Salim, Hadji Riheb, Bouhlal Salah, Hamed Younes, Besser Houda, Ncibi Kaouther

Mineralogia

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2023

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Vol. 54, iss. 1

89--104

EN

The characterization of phosphorite features within specific North African sedimentary series remains incomplete. Hence, the primary aim of this research is to determine the composition of powder patterns and phosphatic allochem fragments within the Jebel Dhyr syncline, situated in northeastern Algeria. By focusing on this region, the study endeavors to investigate the mineralogical properties and geochemical aspects of Paleocene-Eocene phosphorites in the broader context of North Africa. The methodology employed encompasses geological, petrographic, geochemical, and mineralogical analyses of the rocks. To achieve this objective, we have employed various techniques including thin section analysis, atomic absorption spectrometry, and X-ray diffraction (XRD). The geological section across the Jebel Dhyr area has revealed a succession of horizontally layered rocks. These rocks consist of eight prominent phosphorite layers interspersed with carbonate formations. Additionally, occasional thin layers of flint can be observed within these carbonate layers. XRD analysis of the whole rock established the presence of apatite group minerals such as hydroxylapatite, fluroapatite, francolite, and dahllite. Other minerals identified include carbonates, quartz, zeolites, feldspar, clays, sulphides, and gypsum. XRD recordings on the phosphatic allochem grains (pellets, coprolites, intraclasts, and shark teeth) identified different mineral phases, with coprolites and pellets showing hydroxylapatite and fluorapatite, sometimes associated with dahllite, while granules of different forms revealed hydroxylapatite associated with fluorapatite or francolite. Teeth from the Jebel Dhyr phosphate beam showed the systematic presence of fluorapatite. This study provides valuable information for the comprehensive utilization of phosphorus resources in the Algeria-Tunisia border.

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Foraminiferal stratigraphy and palaeobathymetry of Paleocene-lowermost Oligocene deposits (Vezhany and Monastyrets nappes, Ukrainian Carpathians)

Hnylko S., Hnylko O.

Geological Quarterly

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2016

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Vol. 60, No. 1

77--105

EN

Mainly pelagic/hemipelagic deposits of the Vezhany Nappe (Paleocene-Lowermost Oligocene Metova Formation with a high content of planktonic foraminifera) and typical flysch deposits of the Monastyrets Nappe (Paleocene-Eocene Sushmanets Formation with common agglutinated foraminifera as well as the Eocene Drahovo Formation), of the southwestern inner part of the Ukrainian Carpathians have been studied. The Parvularugoglobigerina eugubina Zone (Lower Danian), Acarinina acarinata Zone (Upper Thanetian), Morozovella subbotinae Zone and Morozovella aragonensis Zone (Ypresian), Acarinina bullbrooki Zone and Acarinina rotundimarginata Zone (Lutetian), Subbotina corpulenta Zone and Subbotina vialovi Zone (Upper Priabonian – Lower Rupelian) based on planktonic foraminifera as well as the Rzehakina fissistomata sensu lato Zone (Paleocene), Glomospira charoides–Recurvoides smugarensis Zone (Ypresian), and an assemblage with Haplophragmoides parvulus (latest Mid Eocene-early Late Eocene) based on agglutinated foraminifera have been identified in these deposits. The deep-water agglutinated foraminifera of the “Rzehakina”, “Rhabdammina” and “Paratrochamminoides” assemblages found in the typical flysch deposits of the Sushmanets Formation indicate lower slope to abyssal environments below the CCD. The generic composition and morphological features of planktonic and benthic foraminifera recovered from marls of the Metova Formation suggest pelagic/hemipelagic conditions at bathyal depths above the foraminiferal lysocline.

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Paleogene of the Magura Nappe adjacent to the Pieniny Klippen Belt between Szczawnica and Krościenko (Outer Carpathians, Poland)

Golonka J., Waśkowska A.

Geology, Geophysics and Environment

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2014

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Vol. 40, no. 4

359--376

EN

The present authors investigated the Paleogene deposits of the internal zone of the Magura Basin known as the Krynica Subunit or Krynica zone in Poland. These deposits crop out in the peri-Pieniny zone, in the area between Szczawnica and Krościenko. The oldest flysch deposits belong to the Paleocene - Lower Eocene Szczawnica Formation. This formation is covered by thin-bedded turbidites of the Eocene Zarzecze Formation locally with intercalations of the thick-bedded sandstones of the Krynica Member and Łęcko-type marls. The youngest rocks in this area belong to the Eocene-Oligocene Magura Formation. The Zarzecze Formation occupies a large part of the Krynica zone of the Magura Nappe border structure. Some deposits previously distinguished as the Szczawnica Formation were transferred to the Zarzecze Formation. The foraminiferal assemblages confirm the Eocene age of these deposits.

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Structural inversion of the Pomeranian and Kuiavian segments of the Mid-Polish Trough-lateral variations in timing and structural style

Krzywiec P.

Geological Quarterly

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2006

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Vol. 50, No. 1

151-168

EN

Seven high-quality reflection-seismic lines, calibrated by wells, were interpreted in an effort to assess the timing of inversion and the structural configuration of the Pomeranian and Kuiavian segments of theMid-Polish Trough. Seismostratigraphic analyses of the Upper Cretaceous successions imaged by these seismic lines in the NE and SW marginal troughs of the Mid-Polish Swell document important along-strike stratigraphic and structural changes. Thickness variations of the Upper Cretaceous series, combined with the development of erosional unconformities and associated tectonic deformations indicate that inversion movements commenced during the late Turonian and intermittently persisted into the Maastrichtian and Paleocene. Earliest inversion movements were focused on the margins of the Mid-Polish Trough where Mesozoic sequences are decoupled from the sub-Zechstein series by Zechstein salts. Whereas the NE margin of theMid-Polish Trough is devoid of compressionally reactivated salt structures, its SWmargin is characterized by strong inversion- related salt tectonics. Progressive inversion of the axial parts of the Mid-Polish Trough was accompanied by uplift of its pre-Zechstein floor to and above the level of flanking, non-inverted areas, and by deep truncation ofMesozoic series across the culmination of the evolving Mid-Polish Swell. Inversion movements ceased towards the end of the Paleocene, as evidenced by the burial of the Mid-Polish Swell beneath essentially flat lying Eocene and younger series. Turonian-Paleocene inversion of the Mid-Polish Trough is coeval with the inversion of the Bohemian Massif, the North German Basin and the Sorgenfrei-Tornquist Zone. Inversion of the Mid-Polish Trough is considered to have been controlled mainly by compressional intraplate stresses that built up in the Carpathian foreland during the collision of the Inner Carpathian orogenic wedge with the European passivemargin, attesting to their increasing mechanical coupling, commencing during the Turonian. These stresses relaxed, however, with the end-Paleocene onset of imbrication of the Outer Carpathian domain, reflecting decoupling of the Carpathian orogenic wedge from its foreland.