Genesis of nickel laterites and bauxites in greece during the jurassic and cretaceous, and their relation to ultrabasic parent rocks

Valeton, Ida; Biermann, M.; Reche, R.; Rosenberg, Florian von

doi:10.1016/0169-1368(87)90011-4

Cited by 115 publications

(116 citation statements)

References 24 publications

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“…During the lower Cretaceous they were deeply eroded, subsequently lateritized and transgressively overlain by shallow-water limestones of upper Cretaceous age. The Fe-Ni laterite deposits of central Euboea are resting as in-situ deposits on ophiolites or as mechanical reworked laterite detritus, either on serpentinites or karstified Triassic-Jurassic carbonates and are overlain by Upper Cretaceous limestones [8].…”

Section: Geology -Hydrogeologymentioning

confidence: 99%

“…The region of central Euboea covers part of the Pelagonian zone and apart from the Quaternary alluvial deposits, which cover the lowland areas, consists of a lower sequence of Triassic-Jurassic limestones which pass upwards into silicified limestones and radiolarian mudstones of the schist-chert formation, dated by radiolarian fauna as latest Jurassic to earliest Cretaceous [8,28]. The members of this schist-chert formation are mainly schists, sandstones, red cherts and, in its uppermost parts, olistholiths of ophiolitic rocks.…”

Section: Geology -Hydrogeologymentioning

confidence: 99%

“…Numerous studies have been carried out throughout the world on the geology, geochemistry and genesis of ironnickel deposits [7,8], the specific vegetation linked to ultramafic or serpentine soils and the potential heavy metals availability in these soils [9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

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Distribution and bioavailability of Cr in central Euboea, Greece

Megremi

2010

Open Geosciences

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Plants and soils from central Euboea, were analyzed for Cr (total) , Cr(VI), Ni, Mn, Fe and Zn. The range of metal concentrations in soils is typical to those developed on Fe-Ni laterites and ultramafic rocks. Their bioavailability was expressed in terms of concentrations extractable with EDTA and 1 M HNO 3 , with EDTA having a limited effect on metal recovery. Cr(VI) concentrations in soils evaluated by alkaline digestion solution were lower than phytotoxic levels. Chromium and Ni -and occasionally Zn -in the majority of plants were near or above toxicity levels. Cr(VI) concentrations in plants were extremely low compared to total chromium concentrations. Cr (total) in ground waters ranged from <1 μg.L −1 to 130 μg.L −1 , with almost all chromium present as Cr(VI). With the exception of Cr (total) and in some cases Zn, all elements were below regulatory limits for drinking water. On the basis of Ca, Mg, Cr (total) and Si ground waters were classified into three groups: Group(I) with Cr concentrations less than 1 μg.L −1 from a karstic aquifer; Group(II) with average concentrations of 24 μg.L −1 of Cr and relatively high Si associated with ophiolites; and Group(III) with Cr concentrations of up to 130 μg.L −1 , likely due to anthropogenic activity. Group(III) is comparable to ground waters from Assopos basin, characterized by high Cr(VI) concentrations, probably due to industrial actrivities.

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Section: Geology -Hydrogeologymentioning

confidence: 99%

Section: Geology -Hydrogeologymentioning

confidence: 99%

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Distribution and bioavailability of Cr in central Euboea, Greece

Megremi

2010

Open Geosciences

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“…All of these deposits are allochthonous, lie on karstified Triassic-Jurassic limestones, are conformably overlain by Upper Cretaceous limestones and have been affected by faulting [4][5][6][7][8][9][10][11][12][13][14]16]. The contacts between ore and the overlain Cretaceous and underlain Triassic-Jurassic limestones are irregular, whereas irregular bodies of Cretaceous limestones are enclosed within Fe-Ni-laterite ore.…”

Section: Geological Settingmentioning

confidence: 99%

“…Geochemical characteristics of the Ni-laterite deposits in Lokris have been studied for major and trace elements, including rare earth elements and chemistry of minerals in those deposits [1,[3][4][5][6][7][8][9]. At the Nissi deposits, a strong enrichment of light rare-earth elements (LREE) relative to heavy rare-earth elements (HREE), due to the presence of the authigenic hydroxylbastnaesite-(Nd) minerals, has already been described [8,10].…”

Section: Geological Settingmentioning

confidence: 99%

On the Origin of Bastnaesite-(La,Nd,Y) in the Nissi (Patitira) Bauxite Laterite Deposit, Lokris, Greece

et al. 2017

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A detailed geochemical study and a thorough mineralogical description of the rare-earth elements (REE)-minerals and associated minerals were carried out in two vertical profiles of approximately 4 m length, from the Nissi (Patitira) bauxite laterite deposit, Lokris, Greece, characterized by the presence of goethite in small sizes resembling bacterial cell coated by goethite and a significant REE enrichment. The enrichment of the REE concentrated in bastnaesite-group minerals, the intergrowths between REE-minerals and Al-Ni-silicates with significant sulfur contents and their association with goethite microtextures interpreted as bacteriomorphic, indicate REE remobilization along with iron bio-leaching and re-precipitation on karstified limestone. In addition to the previous-reported hydroxylbastnaesites, a (La,Nd,Y)(CO 3 )F member of the bastnaesite-group associated with Al-Ni-silicates were identified, the stability of which may reflect the dependence on the source rocks and the local variations of pH-Eh. Interaction between downward percolating water and carbonate rocks seems to be a very effective mechanism for REE fluorocarbonates deposition under alkaline and reducing conditions.

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Genesis and mineral transformations in Lower Cretaceous karst bauxites (NE Spain): climatic influence and superimposed processes

2014

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Four outcrops of Lower Cretaceous (Barremian) karst bauxites located in Teruel (NE Spain) were analysed to determine their mineral associations and genesis related to climatic palaeoweathering events and late superimposed kaolinization processes. The materials comprise metric‐sized pisolitic blocks embedded in a clay‐rich red groundmass. Fourteen samples were examined by X‐ray diffraction, optical microscopy, scanning and transmission electron microscopy and the major elements were analysed by inductively‐coupled plasma mass spectroscopy (ICPMS). The samples are composed of kaolinite, gibbsite, goethite, and hematite as the main phases, with diaspore, boehmite, anatase, and rutile as accessory minerals. The results show a complex sequence of mineralogical and geochemical processes that transformed the parent rock into the current bauxite materials. The clay‐rich groundmass constitutes the lateritic parent material of the pisolitic bauxites. In the parent material authigenic kaolinite (e.g. vermicular kaolinite and kaolinite between cleavage sheets of pre‐existing mica) has been observed; Fe oxides formed subsequent to kaolinite. In the pisolitic bauxites, mineralogical and textural evidence indicates that bauxitization took place at the expense of previous kaolinite, with gibbsite post‐dating the other Al hydroxides. The pisolitic bauxites also show a more homogeneous chemical composition and a relative Ti, Al and Zr enrichment. The data are consistent with an intense palaeoweathering event during the Lower Cretaceous (Barremian) under tropical climatic conditions (warm and humid). Several stages probably took place during the bauxitization process, suggesting variations in water saturation conditions. Subsequent karst reactivation stages and related collapses were responsible for the present lithostructure of the deposits and allowed late kaolinization not related to climate to take place. Copyright © 2014 John Wiley & Sons, Ltd.

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Genesis of nickel laterites and bauxites in greece during the jurassic and cretaceous, and their relation to ultrabasic parent rocks

Cited by 115 publications

References 24 publications

Distribution and bioavailability of Cr in central Euboea, Greece

Distribution and bioavailability of Cr in central Euboea, Greece

On the Origin of Bastnaesite-(La,Nd,Y) in the Nissi (Patitira) Bauxite Laterite Deposit, Lokris, Greece

Genesis and mineral transformations in Lower Cretaceous karst bauxites (NE Spain): climatic influence and superimposed processes

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