scholarly journals Genesis of a florencite-bearing kaolin deposit on ordovician schists at Saint-Aubin-des-Châteaux, Armorican Massif, France

2020 ◽  
Vol 120 ◽  
pp. 103445
Author(s):  
Anne Gaudin ◽  
Véronique Ansan ◽  
Jean-Pierre Lorand ◽  
Sylvain Pont
Keyword(s):  
Armorican Massif ◽  
Kaolin Deposit

scholarly journals Microbial nitrification and acidification of lacustrine sediments deduced from the nature of a sedimentary kaolin deposit in central Japan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tetsuichi Takagi ◽  
Ki-Cheol Shin ◽  
Mayumi Jige ◽  
Mihoko Hoshino ◽  
Katsuhiro Tsukimura
Keyword(s):  
Nitric Acid ◽  
Lacustrine Sediments ◽  
Kaolin Clay ◽  
Central Japan ◽  
Inland Lakes ◽  
Fe Oxidation ◽  
Stable Isotopic ◽  
Fe Hydroxide ◽  
Kaolin Deposit ◽  
Dilute Nitric Acid

AbstractKaolin deposits in the Seto-Tono district, central Japan, were formed by intense kaolinization of lacustrine arkose sediments deposited in small and shallow inland lakes in the late Miocene. Based on mineralogical and stable isotopic (Fe, C, N) studies of Motoyama kaolin deposit in the Seto area, we concluded that it was formed by microbial nitrification and acidification of lacustrine sediments underneath an inland lake. Small amounts of Fe–Ti oxides and Fe-hydroxide in the kaolin clay indicated that iron was oxidized and leached during the kaolinization. The field occurrences indicate that leached ferric iron precipitated on the bottom of the kaolin deposit as limonite crusts, and their significantly fractionated Fe isotope compositions suggest the involvement of microbial activity. The C/N ratios of most of the kaolin clay are distinctly higher than those of modern lacustrine sediment. Although, the possibility of a low-temperature hydrothermal origin of the kaolin deposit cannot be completely ruled out, it is more likely that acidification by dilute nitric acid formed from plant-derived ammonia could have caused the kaolinization, Fe oxidation and leaching. The nitrate-dependent microbial Fe oxidation is consistent with dilute nitric acid being the predominant oxidant.

scholarly journals Large-scale relief development related to Quaternary tectonic uplift of a Proterozoic-Paleozoic basement: The Armorican Massif, NW France

2000 ◽  
Vol 105 (B8) ◽  
pp. 19273-19288 ◽  
Author(s):  
Stéphane Bonnet ◽  
François Guillocheau ◽  
Jean-Pierre Brun ◽  
Jean Van Den Driessche
Keyword(s):  
Large Scale ◽  
Tectonic Uplift ◽  
Paleozoic Basement ◽  
Armorican Massif

Rb–Sr and 40Ar/39Ar ages in blueschists from the Ile de Groix (Armorican Massif, France): Implications for closure mechanisms in isotopic systems

2005 ◽  
Vol 220 (1-2) ◽  
pp. 21-45 ◽  
Author(s):  
Valérie Bosse ◽  
Gilbert Féraud ◽  
Michel Ballèvre ◽  
Jean-Jacques Peucat ◽  
Michel Corsini
Keyword(s):  
Armorican Massif

Planalvus (Brachiopoda, Athyridida) from the Lower Devonian of the Armorican Massif, northwest France

1994 ◽  
Vol 68 (3) ◽  
pp. 451-460 ◽  
Author(s):  
Patrick R. Racheboeuf ◽  
Paul Copper ◽  
Fernando Alvarez
Keyword(s):  
New Species ◽  
North America ◽  
Lower Devonian ◽  
Eastern North America ◽  
Lower Carboniferous ◽  
Armorican Massif ◽  
A New Species

Cryptonella? cailliaudi Barrois, 1889, from the Lower Devonian of the Armorican Massif, is tentatively assigned to the athyridid brachiopod genus Planalvus Carter, thus far known only from the Lower Carboniferous of eastern North America. In addition, a new species, Planalvus rufus, is described from the Bois-Roux Formation (Pragian) of Brittany, France. These French species are small brachiopods with complex spiralial and jugal structures, which permit assignment to the order Athyridida.

Palaeozoic history of the Armorican Massif: Models for the tectonic evolution of the suture zones

2009 ◽  
Vol 341 (2-3) ◽  
pp. 174-201 ◽  
Author(s):  
Michel Ballèvre ◽  
Valérie Bosse ◽  
Céline Ducassou ◽  
Pavel Pitra
Keyword(s):  
Tectonic Evolution ◽  
History Of ◽  
Armorican Massif

Fingerprinting the provenance of building stones: a case study on the Louvigné and Lanhélin granitic rocks (Armorican massif, France)

2014 ◽  
Vol 185 (1) ◽  
pp. 13-31 ◽  
Author(s):  
Claudine Malfilatre ◽  
Erwan Hallot ◽  
Philippe Boulvais ◽  
Marc Poujol ◽  
Annick Chauvin ◽  
...  
Keyword(s):  
Building Stone ◽  
Granitic Rocks ◽  
Magnetic Characteristics ◽  
Building Stones ◽  
Intrinsic Variability ◽  
Geological Unit ◽  
Qualitative Variables ◽  
Identity Cards ◽  
Armorican Massif

Abstract Two examples of granitic stones from Brittany (western France) commercialized under the names of “gris-bleu de Louvigné” and “bleu de Lanhélin” were characterized in order to explore how the provenance of a building stone can be traced back with a maximum of confidence. For this purpose, petrographical, geochemical and magnetic characteristics, representing more than 70 quantitative and qualitative variables, were compiled for a total of 32 samples. We have defined two reference populations for these building stones and have extracted their discriminative characteristics. We have then compared four randomly selected samples and two foreign commercial counterparts of these stones to the reference populations. Discriminative variables differ from one case of comparison to the other, which indicates that a combination of various tools and variables will be generally required to unequivocally fingerprint the origin of a given granitic stone. Where several quarries are mining a single geological unit within a composite intrusion, the provenance of a granitic rock can be defined at the scale of the intrusion. In addition, stones coming from two different intrusions from the same batholith can be distinguished. We conclude that the provenance of any granitic building stone is identifiable, especially if the intrinsic variability of a population of samples representative of that stone has been previously circumscribed. This study underlines that the compilation of databases for building stone identity cards is an essential first step toward the creation of official labels guaranteeing stone provenances.

scholarly journals Characterization and Comparison of Geopolymer Synthesized Using Metakaolin Bangka and Metastar as Precursors

2018 ◽  
Vol 67 ◽  
pp. 03022
Author(s):  
Sotya Astutiningsih ◽  
Dicky Tambun ◽  
Ahmad Zakiyuddin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Mechanical Test ◽  
Strength Test ◽  
Thermal Activity ◽  
Metallurgical Properties ◽  
Metakaolin Geopolymer ◽  
Kaolin Deposit

Various aluminosilicate material have been used as precursor for geopolymer. Geopolymer gets its strength from the polycondensation of silicate and alumina. Metakaolin, calcinated kaolin, is pozzolan with the highest alumina and silicate purity. Indonesia, especially Bangka Island, has a large amount of kaolin deposit that being sold at low price. This price could be increased ten times when being sold as metakaolin. This study aimed to compare mechanical and metallurgical properties of commercial metakaolin and Bangka kaolin which calcinated at 700°C. Both metakaolins reacted with NaOH and waterglass as the activator followed by curing at room temperature for 7, 14 and 28 days and elevated temperature of 60°C for 4, 12 and 24 hours. Mechanical properties will be examined by compressive strength and flexural strength test, while the metallurgical properties will be evaluated with SEM, and TAM. The results of the mechanical test will be used to determine which geopolymer will perform well with the microstructure and thermal activity to support the finding. These attempts will be done in order to improve the properties of Bangka metakaolin geopolymer superior to commercial metakaolin.

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