Reaction textures in calc-silicate gneisses from the Tormes gneiss complex: implications for the retrogade P-T-XC02 path

[Abstract] Calc-silicate gneisses from the LowerUnit ofthe Tormes Gneiss Complex,NW Salamanca, exhibit a sequence of reaction textures that have been used to elucidate their retrograde P-T-XC02 path. The highest temperature recorded in the calc-silicates is represented by the wollastonite- and scapolite- (meíoniterich) bearing assemblages which yield at least 7500 C at 6 kbar based on experimental results. The calc-silicates have partially re-equilibrated at lower temperatures (down to 4500 C) as evidenced by the successive reactions: (1) . Wo + Scp + Cal ~ Grt + CO2 ; (2) Wo + CO2~ Cal + Qtz; (3) Scp ~ PI + Cal + Qtz; (4) Grt + CO2 + H20 ~ Ep/Clz + Cal + Qtz ±PI; y (5) Cpx + CO2 + H20 ~ Tr + Cal + Qtz. The cooling down to lower temperatures of4500 C (at P<3 kbar), in the andalusite stability field, is also suggested by the secondary andalusite replacement ofprevious fibrolitic sillimanite in adjacent metapelites. In this paper, mineral devolatilization equilibria are used to constrain the composition ofboth syn- and post-peak-D2 fluids in the deepest exposed levels of the metamorphic complexo The results indicate that during the transitional granulite facies metamorphism, large-scale CO2 advection did not occur

Selective and highly efficient dye scavenging by a pH-responsive molecular hydrogelator

A structurally simple low molecular weight hydrogelator derived from isophthalic acid forms robust pH-responsive hydrogels capable of highly efficient and selective dye adsorption

Tectonothermal evolution associated with crustal escale extension: an hercynian example from the Tormes gneiss dome (NW Salamanca, Iberian Massif)

[Abstract] The tectonothermal Variscan evolution ofthe Tormes Gneiss Dome is controlled by a subhorizontal ductile shear zone of crustal scale and extensional characteristics, that induced a quick exhumation ofthe deep parts ofthe metamorphic complex during crustal thinning. The shearing affected a broad band of metamorphic rocks but, as the temperature decreased, became progressively concentrated in a low-grade ductile detachment that separates two distinct units, characterized by their lithology and different tectonothermal evolution. Kinematic indicators in non-coaxial fabrics show a displacement of the hangingwall to the SE, i. e., parallel to the trend of the foldbelt. The subhorizontal shearing is related to the extensional collapse ofthe variscan crust, previously thickened during the collision tectonics

Selective and highly efficient dye scavenging by a pH-responsive molecular hydrogelator

A structurally simple low molecular weight hydrogelator derived from isophthalic acid forms robust pH-responsive hydrogels capable of highly efficient and selective dye adsorption

Trayectoria metamórfica P-T relacionada con subducción en eclogitas del Complejo de Basamento de Samaná, Cordillera Septentrional, República Dominicana

Lenses of eclogites from the Punta Balandra unit of the Samaná basement complex, Cordillera Septentrional, Dominican Republic, preserve information of the early metamorphic and tectonic history of subduction in the Greater Antilles island-arc system and their collision with the North America plate. For this reason, these rocks were investigated for reconstruction of quantitative metamorphic P-J paths based upon interpretation of meso and microfabrics, mineral assemblages and mineral chemistry, with the help of equilibrium phase diagrams calculated for specific bulk composition in the model system CKNFMASH and isopleths for selected solution end-members. The obtained subduction-related prograde evolution went from garnet-free first and garnet-bearing next lawsonite-blueschist facies to peak eclogue facies conditions at P=22-24 kbar and 7=6 1 0-625sC. The subsequent retrograde P-T path entered the epidote-blueschist (garnet-free) facies and ended within the greenschist facies, retracing the prograde evolution at low-P (i.e. indicates cooling during the exhumation of the rocks). Thus, Samaná basement complex eclogites and hydrated equivalents formed in a intraoceanic subduction zone in which WSW/W-migrating Atlantic lithosphere was subducted beneath the Caribbean plate. Thrust stacking of different tectonic slices can provide the geological framework for exhumation and cooling due to continuous cool underplating and explains the preservation of high-pressure assemblages

Modelling the enantioresolution capability of cellulose tris(3,5-dichlorophenylcarbamate) stationary phase in reversed phase conditions for neutral and basic chiral compounds

[EN] To the best of our knowledge, the prediction of the enantioresolution ability of polysaccharides-based stationary phases in liquid chromatography for structurally unrelated compounds has not been previously reported. In this study, structural information of neutral and basic compounds is used to model their enantioresolution levels obtained from an immobilised cellulose tris(3,5-dichlorophenylcarbamate) stationary phase in reversed phase conditions. Thirty-four structurally unrelated chiral drugs and pesticides, from seven families, are studied. Categorical enantioresolution levels (RsC, 0 = no baseline enantioresolution and 1 = baseline enantioresolution) are established from the experimental enantioresolution values obtained at a fixed experimental conditions. From 58 initial structural variables, three topological parameters (two of them connected to the chiral carbon), and six molecular descriptors (one of them also related with the chiral carbon), are selected after a discriminant partial least squares refinement process. The molar total charge of the molecule at the working pH is the most important variable. The relationships between RsC and the most important structural variables and the drug/pesticide family are evaluated. An explicit model is proposed to anticipate the RsC levels, which provides 100% of correct anticipations. A criterion is introduced to alert about the compounds that should not be anticipated.The authors acknowledge the Spanish Ministerio de Economia y Competitividad (MINECO) and the European Regional Development Fund (ERDF) for the financial support (Project CTQ2015-70904-R, MINECO/FEDER, UE).Martin-Biosca, Y.; Escuder-Gilabert, L.; Medina-Hernandez, MJ.; Sagrado Vives, S. (2018). Modelling the enantioresolution capability of cellulose tris(3,5-dichlorophenylcarbamate) stationary phase in reversed phase conditions for neutral and basic chiral compounds. Journal of Chromatography A. 1567:111-118. https://doi.org/10.1016/j.chroma.2018.06.061S111118156

Paleostress evolution during the exhumation of high-p marbles, Samaná Complex, northern Hispaniola.

The marble of the Samaná complex presents a widespread foliation formed during its exhumation following a general decompressive strain path from high pressure (2.0>P>0.7 GPa) and low temperature (350 MPa during deformation. In contrast, mean flow stress during grain-boundary migration is estimated in |σ1-σ3| 110 MPa Ma-1). All of these data suggest that exhumation always occurred near the brittle-ductile regime of deformation. © 2017, Instituto Geologico y Minero de Espana. All rights reserved.El trabajo ha sido financiado por los proyectos de investigación CGL2010-14890 y CGL2011-23628, auspiciados por el plan nacional I+D+i del Ministerio de Economía y Competitividad del Gobierno de España.Peer reviewe

Effect of alloying elements on laser surface modification of powder metallurgy to improve surface mechanical properties of beta titanium alloys for biomedical application

[EN] Beta-type titanium alloy surfaces (Tie35Nbe10Ta (TNT) and Tie30Nbe4Sn (TNS)) were modified by laser using a power of 1000Wand speed of 6.7 mm/s (Condition A) and a power of 1500 W with speed of 10 mm/s (Condition B). Increasing laser conditions, the thickness of the molten layer was also increased. The initial equiaxed grains changes to quite elongated grains shape. The surfaces were structured under alfa" martensite, alfa and matrix beta. The beta phase content decreased slightly and the alfa" phase increased for both alloys increasing the laser conditions. The condition A increased the elastic modulus (E) and decreased the hardness while condition B did not affect the mechanical properties surface for the TNT system compared to base metal (BM). In TNS system the laser condition A decreased the E and increased the hardness while increasing the laser parameters (Condition B) both E and hardness decreased compared to BM. The laser surface treatment was influenced by the levels of alloying elements present promoting most significant changes in the microstructure and mechanical properties in the TNS system.This work was supported by the Ministerio Espan~ol de Ciencia, Innovaci?on y Universidades, Spain with Grant RTI2018-097810-B-I00, RTI2018-096472-B-I00 and the European Union (EU) through Fondo Europeo de Desarrollo Regional (FEDER) , Spain.Rossi, MC.; Amado, JM.; Tobar, MJ.; Vicente-Escuder, Á.; Yáñez, A.; Amigó, V. (2021). Effect of alloying elements on laser surface modification of powder metallurgy to improve surface mechanical properties of beta titanium alloys for biomedical application. Journal of Materials Research and Technology. 14:1222-1234. https://doi.org/10.1016/j.jmrt.2021.07.037122212341

Effect of Alloying Elements on Laser Surface Modification of Powder Metallurgy to Improve Surface Mechanical Properties of Beta Titanium Alloys for Biomedical Application

[Abstract] Beta-type titanium alloy surfaces (Tie35Nbe10Ta (TNT) and Tie30Nbe4Sn (TNS)) weremodified by laser using a power of 1000 W and speed of 6.7 mm/s (Condition A) and a powerof 1500 W with speed of 10 mm/s (Condition B). Increasing laser conditions, the thicknessof the molten layer was also increased. The initial equiaxed grains changes to quiteelongated grains shape. The surfaces were structured undera00martensite,aand matrixb.Thebphase content decreased slightly and thea00phase increased for both alloysincreasing the laser conditions. The condition A increased the elastic modulus (E) anddecreased the hardness while condition B did not affect the mechanical properties surfacefor the TNT system compared to base metal (BM). In TNS system the laser condition Adecreased the E and increased the hardness while increasing the laser parameters (Con-dition B) both E and hardness decreased compared to BM. The laser surface treatment wasinfluenced by the levels of alloying elements present promoting most significant changesin the microstructure and mechanical properties in the TNS systemThis work was supported by the Ministerio Español de Ciencia, Innovación y Universidades, Spain with Grant RTI2018-097810-B-I00, RTI2018-096472-B-I00 and the European Union (EU) through Fondo Europeo de Desarrollo Regional (FEDER), Spai

Subdivisión geoquímica del Arco Isla Circum-Caribeño, Cordillera Central Dominicana: Implicaciones para la formación, acrecion y crecimineto cortical en un ambiente intraoceánico

The Upper Cretaceous-Eocene Circum-Caribbean island-arc system (AICC) is a complex collage of crustal units or terranes s.l. which have formed and accreted within an intra-oceanic environment since Late Jurassic-Early Cretaceous times. In the Cordillera Central of the Dominican Republic these terranes are represented by several tectonostratigraphic units, that define a pre-Aptian-Albian deformed and metamorphosed basement, over and into which the igneous rocks of the AICC were extruded or intruded. Basement sequences can be subdivided into: (1) a plume-related Duarte terrane (plateau I); (2) a primitive arc-related Maimón-Amina terrane, which includes intra- or back-arc N-MORB units (Río Verde Complex) with a subduction geochemical imprint; and (3) the Loma Caribe peridotite terrane of mantle provenance. Two successive stages of the arc growth are superposed: an Early Cretaceous arc tholeiite stage with boninitic affinities (arc I), and a Late Cretaceous-Eocene calc-alkaline stage (AICC; arc II). The arc I stage is not recorded in the Duarte terrane but is represented in the Maimón-Amina terrane by the Río Verde Complex, the Maimón Forma-tion and the Peralvillo Norte Formation. In the Duarte terrane, the arc II growth stage include the Siete Cabezas Formation (Cenomanian- Maastrichtian, plateau II) and the fill of an intra-arc basin by the Tireo Formation (Cenomanian-Maastrichtian). In the Maimón-Amina terrane, the arc II growth is represented by the Las Lagunas and Peralvillo Sur Formations. The former lies unconformably on rudist-bearing limestone of Albian age (Hatillo Limestone). The Jautía gabbro-norite batholith and the calc-alkaline foliated and non-foliated tonalitic plutons of Late-Cretaceous-Early Eocene age intrude the rocks of the Duarte terrane except the Siete Cabezas Formation. Deformation and metamorphism of the pre-Aptian-Albian basement is a consequence of the collision of the Duarte plateau terrane with the Caribbean primitive island arc (Maimón-Amina terrane), that caused the emplacement of the Duarte terrane with a fragment of oceanic lithosphere (ophiolite). The interpretation of the geological and geochemical data support a tectonomagmatic model, which relates the compositional evolution of the intruded and extruded magmas in this segment of the AICC, with a flip in the subduction polarity under the primitive arc after the Aptian/Albian collision