 More recent volcanic activity includes the formation of the Ankaratra Massif over the past 5 million years, and Montagne d'Ambre, which erupted from 50 to 2 million years ago.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.