Alluvial xenotime and heavy minerals assemblage from the northern edge of Nisa-Albuquerque Batholith, eastern Portugal: Provenance and geochemical implications

摘要: Abstract The xenotime-bearing heavy mineral assemblages present in the alluvial samples from Vila Velha de Rodao, Nisa, Povoa e Meadas and Sto. Antonio das Areias, localized northern edge of Nisa-Albuquerque Batholith, Eastern Portugal, were studied detail. insights for provenance came analysis drainage network composition regional outcropping lithologies. Since xenotime is a with economic interest, motivation current work its contribution exploration studies, considering potential information contained samples. In study region, minerals their morphology reflect clearly mineralogy relative distance to source, respectively. direct Nisa granite (late Carboniferous), increase concentration decrease monazite, apatite, zircon, ilmenite iron oxide concentration, W (Nisa) E (Sto. Areias), matches P2O5 REE, CaO, Zr, TiO2, Fe2O3 contents rocks. geochemical signature reveals an igneous characterized by characteristic strong Eu negative anomaly REE patterns. Their YPO4 values (72–78 mol%) are similar Erzgebirge (Germany) granites. high Y/Ho (50–71) and, some cases, downward kinks at Ho plots, suggest generation late stages crystallization association siliceous evolved magmatic system. slight HREE xenotime, E, anomalies normalized pattern those identified granite, which supports sourcing these granitic genetic development batholith chemical zonation (more E) seems have favoured instead monazite eastern end area Areias). Supporting signature, zircons also display morphological typologies that compatible peraluminous granites formed temperatures 600–700 °C, possibly granite. all grains show same affinity, this leads hypothesis Rodao sample, Cenozoic sedimentary rocks, has been transported area, after disaggregated granites, most probably braided anastomosing erratically sandy channels, explains actual position opposite bank Tagus river. This phosphate deposited other sediments tectonic depressions subsequently included formation greater Ca, Th U inclusions/substitutions can be explained mobility provided during geological processes.