Mineralogical and structural characterization of massive sulphide deposits in the Iberian Pyrite Belt using hyperspectral digital outcrops

In this contribution, we present integrated hyperspectral and photogrammetric models from three abandoned open pit mines in the Iberian Pyrite Belt: Corta Atalaya, Tharsis, and Peña de Hierro. On those three examples, we showcase the usefulness of these data for the characterization of volcanogenic massive sulphide (VMS) mineral deposits. The digital outcrop models are generated by co-registering Structure-from-Motion photogrammetric point clouds of the mine faces with radiometrically corrected hyperspectral images in the visible–near and short-wave infrared range. We then use advanced unmixing and supervised classification techniques to distinguish and map the massive sulphide and stockwork mineralization, their sedimentary, volcanic and volcaniclastic host rocks, and domains of hydrothermal and supergene alteration. The enhanced outcrop models also enable a semi-automatic delineation of discontinuities on the point clouds guided by changes in the hyperspectral attributes, and an estimation of structure orientations from their intersection with the surface to derive simple 3D geological models.