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Showing 1 to 17 of 17 for “"phosphorite"”.
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The petrography and major element geochemistry of the phosphorite nodule deposits on the Agulhas Bank, South Africa
… Bank have proved the existence of a widespread phosphorite nodule deposit, considered to be essentially in situ. The pebble to boulder sized nodules recovered have been classified into two conglomeratic and three non-conglomeratic classes. The latter classes comprise (i) phosphatized …
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Sedimentological study of the western zone of the Lady Annie phosphate deposit, Queensland, Australia
… determine the sedimentary parameters controlling phosphorite deposition and to identify the factors influencing phosphate grade. The study was concentrated on the Western Zone of the Lady Annie deposit which, together with the Lady Jane deposit, occurs in an elongate north-south outlier surrounded …
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Sedimentological study of the western zone of the Lady Annie phosphate deposit, Queensland, Australia
… determine the sedimentary parameters controlling phosphorite deposition and to identify the factors influencing phosphate grade. The study was concentrated on the Western Zone of the Lady Annie deposit which, together with the Lady Jane deposit, occurs in an elongate north-south outlier surrounded …
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The sedimentology and palaeoecology of the Coralline Crag (Pliocene) of Suffolk
… The stratigraphically lowest facies is a nodular phosphorite horizon resting on an eroded surface of London Clay (Eocene). The components of the phosphorite deposit include phosphatic pebbles and cobbles and assorted phosphatised fossils which were derived from a variety of sources including a …
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Petrographic and geochemical evidence for the origin of phosphorites and phosphate rocks from the West Coast of South Africa
The onshore marine phosphorite and aluminium phosphate deposits of Varswater Quarry (near Langebaanweg), Bomgat (near Hoedjiespunt), Kreefte Bay and Konstabelkop were studied to determine the origin of the various deposits.
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The oligo-miocene sediments of the Maltese Islands
… water deposits, the analysis of the associated phosphorite conglomerate beds of the former indicating that dominant transport of clasts was from the west, in an area of primary phosphorite and glauconite development. The Greensand Formation is re-defined on the basis of sedimentology, and the …
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Constraining the Ediacaran-Cambrian boundary in South China using acanthomorphic acritarchs and Palaeopascichnus fossils
… because of their wide distribution in chert-phosphorite layers intercalated with carbonates and shales, thus allowing their biostratigraphic occurrences to be calibrated with small shelly fossil (SSF) biostratigraphy and carbon isotope chemostratigraphy. Acanthomorphic acritarchs of the …
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Benthic foraminifera from the Orange-Luderitz shelf, southern African continental margin
… were distinguished on the basis of glauconite or phosphorite infillings, anomalous, distributions, and tests which are worn, battered, and partially dissolved. Bibliography: p. 62-65.
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Iron minerals in sedimentary phosphorites of the southeastern United States
… Florida, North Carolina, and central Tennessee phosphorite deposits account for 90% of the marketable phosphate produced in the United States. Scanning electrons and reflected light microscopy reveals that the iron-bearing minerals associated with these sedimentary phosphorites are related to …
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Microbial Communities Associated with Phosphoclast-bearing Sediments of the Benguela Upwelling Zone
… Calcium phosphate mineral deposits, known as phosphorites, are also the primary source of P for agriculture. Understanding phosphorite formation may improve management of P resources. However, the processes that mediate calcium phosphate mineral precipitation in certain marine pore waters …
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The Neoproterozoic São Francisco Basin, central Brazil: tectonic evolution, paleoclimate, and mineral systems
… 2, composed of neritic limestone, siltstone, and phosphorite, is unconformably overlain by dolostone and stromatolitic reefs of Sequence 3. A karst unconformity with sulphide deposits caps Sequence 3. Organic-rich, pyritiferous, deep-water, marine siltstones of Sequence 4 are overlain by shallow …
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Sedimentology and diagenesis of Ediacaran phosphorites from South China
Ediacaran phosphorites provide a principal record of the paleoenvironmental and paleoecological conditions of the oceans during Earth's second major oxygenation and the evolution of complex life. Although the fidelity of this record is high, diagenesis and metamorphism frequently alter or overprint …
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Neogene to quaternary foraminifera from the western margin of southern Africa
… and the overlying Plio-Pleistocene age of the phosphorite-rich unit supported by planktic indicator species Globorotalia truncatulinoides and Globorotalia (Globoconella) inflata. Middle Miocene foraminifera reflect a warmer, oligotrophic, subtropical, deeper environmental setting in contrast to …
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Sedimentation on the continental margin off the Orange River and the Namib Desert
… which are overlain by glauconitic conglomeratic phosphorites. Quartz-free algal limestones are found both on the Orange Banks and on the tip of Tripp Seamount. Authigenic pyrite and gypsum were found in two samples of semi-consolidated Neogene clay on the slope off Lüderitz. Pyrite is formed by …