 A NW-SE trending sinistral shear belt separates northern and southern crustal terranes.The Ampanihy ductile shear zone was created by flattening events associated with granulite metamorphism, isoclinal folding, flattened sheaths, steep to vertical foliations and sheath-like geometry of massif-type anorthosite bodies.The Maevarano Formation, dated to late Maastrichtian age, has provided a diverse faunal assemblage, including the giant frog "Beelzebufo", gondwanathere mammals, dinosaurs, crocodylians and other groups.