Fe-Mn oxide indications in the feeder and mound zone of the Jurassic Mn-carbonate ore deposit, Úrkút, Hungary

Abstract The Úrkút manganese deposit, one of the World's largest, is located in the central part of the Transdanubian Range, western Hungary. The deposit is interbedded with Mesozoic limemarlstone. The Fe-Mn-oxide indications of a feeder and mound zone embedded in limemarlstone at the footwall of the Mn-carbonate ore deposit were studied using 45 samples (Úrkút Mine, Shaft III, deep level). Microstructural and textural (optical microscopy, SEM-EDS) observations, mineralogy (XRD-μXRD), and geochemistry (ICP, C and O by IR-MS) were used to characterize the host marlstone and the Fe-Mn oxides of the feeder and mound zone. High-resolution in situ and bulk organic matter analyses were performed for the first time using GC–MS, FTIR-ATR, and Raman spectroscopy. Stromatolite-like, filamentous and coccoid microstuctures built up of Fe-Mn-oxides (ferrihydrite, goethite, manganite, pyrolusite, hollandite, birnessite, hausmannite) and silica occur in the micritic marlstone host rock among common calcite biodebris (microfossils and Echinozoa fragments) and rare detrital clasts (quartz, feldspar). The clay minerals occur as greenish patches in the limemarlstone and show boring traces. The calcite matrix of the limemarlstone and idiomorphic dolomite are authigenic. δ13CPDB values of the carbonate in the host limemarlstone reflect greater organic matter contributions approaching the mineralized areas (0.64 to − 21.35‰). Temperature calculation based on δ18OSMOW values of the carbonate, assuming equilibrium conditions, show elevated temperatures toward the mineralized areas (9.93 to 29.87‰). In places, the Mn oxides appear with Fe oxides in laminated, micro-stromatolite-like structures. In these oxide zones, variable kinds of organic compounds occur as intercalated microlaminae identified by FTIR and Raman line-profile analyses as aromatic hydrocarbons. Results indicate that metal-bearing fluids infiltered the unconsolidated micritic limemarl. Fe-oxide enrichment occurred most probably through iron oxidizing microbes under suboxic, neutrophilic conditions, while Mn oxide formed most probably by active surface catalyses. At the sediment/water interface, Fe-Mn-oxide stromatolite mounds (chimneys) formed in rift zones from the discharge of fluids of elevated temperature. The host marl itself may have originated by microbially mediated reactions (clay minerals and calcite micrite)

Synthesis of novel crown ether-squaramides and their application as phase-transfer catalysts

t: This work presents the synthesis of six new phase-transfer organocatalysts where the 15 squaramide unit is directly linked to the nitrogen atom of an aza-crown ether. Four chiral skeletons, 16 namely hydroquinine, quinine, cinchonine (cinchonas), and α-D-glucopyranoside were responsible 17 for the asymmetric construction of an all-carbon quaternary stereogenic center in α-alkylation and 18 Michael addition reactions of malonic esters. We intended to investigate the effects of different chi- 19 ral units and that of crown ethers with different sizes on catalytic activity and enantioselectivity. 20 During extensive parameter investigations, both conventional and emerging green solvents were 21 screened, providing valuable α,α-disubstituted malonic ester derivatives with excellent yields (up 22 to 98%). Furthermore, the products are amenable to chemoselective transformation and could be 23 successfully converted to the corresponding α,α-disubstituted amino acid derivatives through Cur- 24 tius rearrangement

Increased micronutrient content (Zn, Mn) in the 3Mb(4B) wheat- Aegilops biuncialis substitution and 3Mb.4BS translocation identified by GISH and FISH

3Mb Triticum aestivum L. (Mv9kr1)-Aegilops biuncialis Vis. (MvGB642) addition lines were crossed with the Chinese Spring ph1b mutant genotype (CSph1b) to produce 3Mb-wheat chromosome rearrangements. In the F3 generation, 3Mb(4B) substitution lines and 3M b.4BS centric fusions were identified with in situ hybridization using repetitive and genomic DNA probes, and with SSR markers. Grain micronutrient analysis showed that the investigated Ae. biuncialis accession MvGB382 and the parental line MvGB642 are suitable gene sources for improving the grain micronutrient content of wheat, as they have higher K, Zn, Fe, and Mn contents. The results suggested that the Ae. biuncialis chromosome 3M b carries genes determining the grain micronutrient content, as the 3Mb.4BS centric fusion had significantly higher Zn and Mn contents compared with the recipient wheat cultivar. As yield-related traits, such as the number of tillers, the length of main spike, and spikelets per main spike, were similar in the 3Mb.4BS centric fusion and the parental wheat genotype, it can be concluded that this line could be used in pre-breeding programs aimed at enriching elite wheat cultivars with essential micronutrients. | Des lignées d'addition 3Mb Triticum aestivum L. (Mv9kr1) – Aegilops biuncialis Vis. (MvGB642) ont été croisées avec le mutant Chinese Spring ph1b (CSph1b) afin de produire des réarrangements chromosomiques 3Mb–blé. Au sein de la génération F3, des lignées de substitution 3Mb(4B) et des fusions centriques 3Mb.4BS ont été identifiées par hybridation in situ au moyen de sondes d'ADN répété ou génomique ainsi qu'avec des marqueurs SSR. Une analyse de la composition du grain en matière de micronutriments a montré que l'accession étudiée de l'Ae. biuncialis (MvGB382) et la lignée parentale MvGB642 constituent des sources valables pour améliorer le contenu en micronutriments chez le blé, du fait qu'elles ont une teneur accrue en K, Zn, Fe et Mn. Ces résultats suggèrent que le chromosome 3Mb de l'Ae. biuncialis porte des gènes contribuant a` déterminer le contenu en micronutriments puisque la fusion centrique 3Mb.4BS présentait un contenu en Zn et en Mn significativement supérieur a` la variété de blé réceptrice. Puisque les composantes de rendement comme le nombre de talles, la longueur de la tige principale et le nombre d'épillets par épi étaient semblables chez la fusion centrique 3Mb.4BS et chez le génotype de blé parental, les auteurs en concluent que cette lignée pourrait s'avérer utile dans des programmes de pré-sélection visant a` accroître la teneur en micronutriments essentiels chez les cultivars élites de blé. [Traduit par la Rédaction