Mineral paragenesis in the variscan metallogeny of Spain

Abstract

The mineral paragénesis which characterize the most important Spanish ore deposits related to the Variscam metallogeny are given in this paper. In the first part, the limits of the Hercynian orogenic belt of the Iberian Peninsula are established, and summarized the main geological, tectonic and metallogenic features of the basement which makes up both the Hesperian Massif and the inner zones of the Alpine orogen. In the second part, the paragenesis are defined. This is made according to their mineralogy and host rocks, which allows to classify the mineralogical associations in three groups : Variscan, pre-Variscan, and late-Variscan. The first group is the most important as it is formed by the strictly Variscan mineral associations. It includes 32 paragenesis —(K.U-Ce), (k.Be), (na.U-Ti), (na-Li), (k.Na-Sn), (q.Sn), (q.Sn-W), (q.W), (q.W-B), (q.As-U), (q.Mo-Au), (q-P), (sk.W-Mo), (sk.Pol-Fe), (q.Co-Ni-Bi), (Co-Ni-Cu), (q.Ba-Pb-Ag), (q.-Cu), (q.Pb-Ba), (q.Pb-Zn), (f.Zn-Pb), (c.Zn), (e.Fe-Cu), (e.Fe-Pol), (e.q-Mn), (q.U-Cu), (q.U-Fe), (q.U-BG), fq.U-F), (Sb), (q.Sb), (Sb-W) and (Sb-Hg)— of pegmatitic, vein-like, metamorphic and exhalative-sedimentary origin. In the second group, 12 igneous and metamorphic paragenesis —(a.Ti-Zr), (a.Sn-Ce), (sk.W), (Fe), (v.Fe-Pol), (v.Fe-Cu), (v.Ba-Mn), (v.Hg-Fe), (m.Ti-Cr), (m.U-Ni-Co), (m.BGPC) and (m.Hg-Ba)— are included. Finally, in the third group, 2 paragenesis —(F.Ba) and (Ba-Fe)—, one sedimentary and other hydrothermal, occur in Triassic sediments, the age of which is older than 220 m.y. This age has been considered as the upper limit of the Alpine metallogenic processes.