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Almaty, Kazakhstan

Erkul F.,Akdeniz University | Erkul S.T.,Akdeniz University | Ersoy Y.,Dokuz Eylul University | Uysal I.,Karadeniz Technical University | Klotzli U.,Center for Earth science

Plutonic associations in the central Menderes metamorphic core complex are suitable rocks in order to understand the magma forming processes in extended terrains. Syn-extensional Salihli and Turgutlu granitoids have granodioritic composition and contain monzonitic and monzodioritic microgranular enclaves. They are transitional metaluminous/peraluminous and high-K calc-alkaline in character and are located on I- and S-type transition. Salihli and Turgutlu granodiorites are geochemically similar to each other while their microgranular enclave chemistry is in contrast with low SiO2 and high Mg#values. Mineral chemistry data from granodiorites and mafic microgranular enclaves confirm their shallow emplacement at about 7km. Geochemical modelling suggests that syn-extensional granitoids were derived from the mixing of mantle and lower crustal components, which were finally modified by a significant amount of upper crustal contamination and fractional crystallization processes at shallow crustal levels. Early-Middle Miocene syn-extensional granitoids across the Aegean region form a magmatic belt associated with roll-back of the Aegean lithosphere slab. Roll-back induced magmatism together with ductile deformation in western Turkey ceased after cooling of the Salihli granodiorites at 12.2Ma. But core-complex related magmatism was continuous in the Cycladic metamorphic core complex during Late Miocene and was followed by an active arc volcanism in the southern Aegean. Such abrupt change from ductile to brittle mode of extension in western Turkey can be explained by opening of a slab window on the Aegean lithosphere slab, which would lead to upwelling of fertile subslab asthenospheric mantle, forming transitional and finally OIB-type basalts. © 2013 Elsevier B.V. Source

Schenkeveld W.D.C.,Wageningen University | Schenkeveld W.D.C.,Center for Earth science | Reichwein A.M.,Akzo Nobel | Temminghoff E.J.M.,Wageningen University | van Riemsdijk W.H.,Wageningen University
Plant and Soil

Aim: A mechanism of action for the performance of Fe chelates as soil-applied fertilizer has been hypothesized by Lindsay and Schwab (J Plant Nutr 5:821-840, 1982), in which the ligand participates in a cyclic process of delivering Fe at the root surface and mobilizing Fe from the soil. This "shuttle mechanism" seems appealing in view of fertilizer efficiency, but little is known about its performance. The chelate FeEDDHA is a commonly used Fe fertilizer on calcareous soils.Methods: In this study, the performance of the shuttle mechanism has been examined for FeEDDHA chelates in soil interaction and pot trial experiments.Results: The specificity of EDDHA ligands for chelating Fe from soils of low Fe availability is limited. Experimental support for a shuttle mechanism in soil-plant systems with FeEDDHA was found: specific metal mobilization only occurred upon FeEDDHA-facilitated Fe uptake. The mobilized metals originated at least in part from the root surface instead of the soil.Conclusion: The results from this study support the existence of a shuttle mechanism with FeEDDHA in soil application. If the efficiency of the shuttle mechanism is however largely controlled by metal availability in the bulk soil, it is heavily compromised by complexation of competing cations: Al, Mn and particularly Cu. © 2014 Springer International Publishing Switzerland. Source

Adhikari B.R.,Tribhuvan University | Wagreich M.,Center for Earth science
Austrian Journal of Earth Sciences

The Thakkhola-Mustang Graben of central Nepal Himalaya represents the Cenozoic extensional tectonic phase of the Tibetan Plateau and the whole Himalaya. The graben is an asymmetrical basin containing a more than 850 m thick pile of Neogene to Quaternary sediments. These sediments have been divided into five formations: the Tetang Formation, the Thakkhola Formation, the Sammargaon Formation, the Marpha Formation and the Kaligandaki Formation. Younger Sammargaon and Marpha formations (Plio-Pleistocene) are lying disconformably above the older Tetang and Thakkhola formations (Miocene/Pliocene). The Thakkhola and Tetang formations are separated by an angular unconformity. The Kaligandaki Formation of Holocene age is in cut and fills relation with Marpha Formation. Six architectural elements and twelve lithofacies from 18 outcrop locations representing Neogene sediments of the Thakkhola- Mustang Graben have been defined and described. The associations are: (I) matrix-rich conglomerate-gravelly sandstone association, (II) matrix-rich conglomerate with sandstone and mudstone and (III) massive siltstone with mudstone, alternating with carbonate layers. Lithofacies I includes matrix-supported, moderately sorted massive gravel (Gmm), poorly sorted clast-supported gravel (Gci), imbricated to massive conglomerate (Gmg) and poorly sorted pebble and cobble sized conglomerate with laminated sandstone (Gh). Moderately thick matrix-rich conglomerate with sandy matrix (Gt), coarse to very coarse stratified sandstone (Sp), massive grey to black mudstone (Fr) and well sorted pebbly conglomerate with laminar grey siltstone (Fl) characterized the lithofacies assemblages II. Fine sandstone with carbonate deposits of lithofacies assemblages III consists of poorly consolidated laminated to massive calcareous mud (C), silt and mud with organic layers (Fsm), structureless conglomerate streaks within mudstone and sandstone beds (Gcm) and laminated yellow colored carbonate (P) lithofacies. Sediments were deposited in alluvial fan, braided river, fluvio-lacustrine and lacustrine environments. The materials are derived mainly from the Paleozoic and Mesozoic basement highlands. Periodic appearance of carbonate layers indicate the damming of paleo Kali Gandaki River in different time intervals. The graben is interpreted as a half-graben along a western main boundary fault (Dangardzong Fault). Palynology data indicate an evolution from warm and relatively humid to more arid during the Miocene/Pliocene. Source

Schenkeveld W.D.C.,Wageningen University | Schenkeveld W.D.C.,Center for Earth science | Weng L.P.,Wageningen University | Reichwein A.M.,Akzo Nobel | And 2 more authors.
European Journal of Soil Science

Ferric ethylene diamine-N,N'-bis(hydroxy phenyl acetic acid) (FeEDDHA)-based iron (Fe) fertilizers are commonly applied to plants grown on calcareous soils and comprise a mixture of FeEDDHA components. Upon application to the soil, the pore water concentrations of the active ingredients racemic and meso o,o-FeEDDHA show a gradual decline unrelated to plant uptake or biodegradation. In the present study, the potential of soil copper (Cu) to reduce the effectiveness of FeEDDHA-based fertilizers in calcareous soils by displacing Fe from o,o-FeEDDHA has been evaluated through modelling and experiments. Predictions with mechanistic multi-surface models show that there is a thermodynamic basis for assuming that under equilibrium conditions a certain fraction of o,o-EDDHA ligands in soil solution can be chelated to Cu, in particular for meso o,o-EDDHA. The large affinity of o,o-CuEDDHA for binding to the soil solid phase, demonstrated in a batch interaction experiment, greatly increases the potential impact of Cu competition on the o,o-FeEDDHA solution concentration; for a given quantity of o,o-CuEDDHA in soil solution, a much larger quantity of o,o-CuEDDHA is adsorbed to the solid phase. Finally, evidence for the actual displacement of Fe from o,o-FeEDDHA by Cu was found in a soil incubation study. With these results, the boundary conditions are met for explaining the observed gradual decline in o,o-FeEDDHA concentration with Cu competition. © 2015 British Society of Soil Science. Source

Bissengaliyeva M.R.,Institute of Problems of Complex Development of Mineral Resources | Knyazev A.V.,Novgorod State University | Bekturganov N.S.,National Scientific and Technological Holding Parasat | Gogol D.B.,Institute of Problems of Complex Development of Mineral Resources | And 4 more authors.
Journal of the American Ceramic Society

A new sample of triple oxides - barium-thulium bismuthate Ba 2TmBiO6 with perovskite structure - has been synthesized by ceramic technology. The unit cell parameters of the sample and the coefficients of thermal expansion have been determined by the method of X-ray analysis. Thermal properties of the sample have been studied by DTA over the temperature range of 293-1473 K. The heat capacity of the compound has been measured over the range of 5-320 K by vacuum adiabatic calorimetry. Thermodynamic functions of the compound have been determined based on the heat capacity data. © 2013 The American Ceramic Society. Source

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