The Grosina Nappe forms a series of tectonic klippes on the southwestern parts of the Campo Nappe along a distinct mylonitic zone associated with top-NW to top-N senses of shear of Cretaceous age that possibly reworked a Jurassic décollement zone. The amphibolite-facies Variscan basement of the Grosina Nappe is in parts similar to that of the underlying Campo Nappe. However, the basement of the Grosina Nappe differs in that orthogneisses are much more frequent, and, additionally, in that there is often a pervasive greenschist-facies metamorphic overprint of the older high-grade fabrics. The root zone of the Grosina Nappe most probably occurs at the southern margin of the Campo Nappe Complex and in the immediate footwall of the tectonically higher Tonale Nappe.