V-RICH MINERALS IN CONTACT-METAMORPHOSED SILURIAN SEDEX DEPOSITS IN THE POBLET AREA, SOUTHWESTERN CATALONIA, SPAIN
The Lower Llandoverian metasedimentary rocks of the Prades Mountains, southwestern Catalonia, Spain, consist of interstratified anorthite-rich beds, chert beds, phosphate beds, sulfide-rich black shale (with mainly pyrrhotite and minor chalcopyrite), massive sulfide lenses and calc-silicate beds. These metasedimentary rocks are anomalously enriched in V and Cr, and have disseminated minerals of precious metals: mainly sperrylite and palladian lollingite. The V- and Cr-rich associations are the result of an isochemical metamorphism of V- and Cr-rich protoliths. The contact metamorphism of V-rich shale produced metapelitic hornfels with V-rich aluminosilicates and V–Cr oxides. The occurrence of V oxides in apparent equilibrium with V-rich silicates suggests a limit for the V and Cr contents in these aluminosilicates at the conditions of thermal metamorphism. On the other hand, metamorphism of anorthite- and V-,Cr-rich sedimentary rocks produced V- and Cr-rich silicates, such as goldmanite, V-rich amphiboles, V-rich titanite and V-rich allanite.
Geochemical evidences of sedimentary-exhalative origin of the shale-hosted PGE–Ag–Au–Zn–Cu occurrences of the Prades Mountains (Catalonia, Spain): trace-element abundances and Sm–Nd isotopes
Abstract The Llandoverian black shales of the Prades Mountains, SW Catalonian Coastal Ranges, contain several metamorphosed stratiform sulfide deposits. The mineralized interval, up to 30 m in thickness, consists of interbedded sulfide-rich (mostly pyrrhotite) shales, feldspar-rich layers and apatite beds. The ore contains Zn, Cu, Pb, Au, Ag and PGE. Whole-rock trace-element analyses were performed by ICP-MS, and the results were normalized to NASC reference standard. The REE patterns show enrichment in Eu (La) and a strong depletion in Ce. This distribution is compatible with REE mostly inherited from seawater, but a significant hydrothermal component is inferred for Eu. Profiles of redox-sensitive trace elements show great V, Cr, Ni, Co, Mo and U enrichments with respect to NASC standard. Part of this enrichment could derive from a direct precipitation from seawater, favoured by the euxinic conditions of the Silurian basin. Nevertheless, V (up to 5444 ppm) and Cr (up to 640 ppm) contents would require additional sources. These elements could be scavenged from seawater by exhalative particles in a hydrothermal derived plume that finally accumulated on the seafloor. In contrast, high Ni, Co and Mo values could be of hydrothermal origin. Sm–Nd isotopic analyses of feldspar-rich layers yielded an isochron age of 437±57 Ma (Llandoverian). These results, as well as the fine-grained textures, the lack of evidences of replacement and the pre-deformational and pre-metamorphic character support the syngenetic origin of the mineralization. Trace-element geochemistry and Sm–Nd isotopes are consistent with a submarine-exhalative origin of the mineralization processes, and suggest that the feldspar-rich levels are metaexhalites.
Adsorption of immunoglobulin Y in supermacroporous continuous cryogel with immobilized Cu(2+) ions.
The influence of temperature, pH and ionic strength on the adsorption of Immunoglobulin Y (IgY) in IDA-Cu(2+) cryogel system was studied by batch equilibrium measurements. The adsorptive equilibrium data were obtained at 17 and 27°C, pH 5.0 and 6.5, and at ionic strength of 50 and 200mmolL(-1) NaCl. Langmuir, Freundlich and Langmuir-Freundlich models were fitted to equilibrium data, while the enthalpy of adsorption of IgY in IDA-Cu(2+) cryogel system was calculated through Van't Hoff analysis. The binding of IgY on cryogel was stronger at 27°C and lowest pH and ionic strength values, with apparent maximum adsorption capacity of 27mgg(-1). The adsorption of protein in the resin was spontaneous in all analyzed cases. The results provide valuable information to enable the improvement of IgY purification processes.