Las turmalinitas estratiformes ordovicicas de Latedo en el flanco S del sinforme de Alcañices (Zamora)

Abstract

The interstratified tourmalinites found within the volcanosedimentary levels of the «Cabeza de las Viñas» Formation (Lower Ordovician, Southern limb of the Alcañices Synform, Zamora) have been studied from the geological mineralogical and chemical points of view. The turmalinites, that add up to 70 % of the whole rock, have been studied under the petrographic microscope and analized by means of the microprobe and wet chemistry. Results obtained indicate that the tourmalines belong to the schorlite-dravite series. Also texto-structural analysis of this nearly monomineralic rocks suggest that the tourmline resulted of the metamorphism of pelitic sediment enriched in boron during o post the first main phade of Hercynian deformation. The origin of the Boron is attributed to exhalative-hidrothermal processes, associated to the volcanism of the region.