Alps vs. Appennines: The paradigm of a tectonically asymmetric Earth

Alps and Apennines developed along opposite subductions, which inverted the tethyan passive continental margins located along the boundaries of Europe, Africa and the Adriatic plates. The Alps have higher morphological and structural elevation, two shallow, slow subsiding foreland basins. The Apennines have rather low morphological and structural elevation, one deep and fast subsiding foreland basin. While the Alps sandwiched the whole crust of both upper and lower plates, the Apennines rather developed by the accretion of the upper crust of the lower plate alone. Alpine relics are boudinated in the hangingwall of the Apennines, stretched by the Tyrrhenian backarc rifting. Relative to the upper plate, the subduction hinge moved toward it in the Alps from Cretaceous to Present, whereas it migrated away in the Apennines from late Eocene to Present, apart in Sicily where since Pleistocene(?) it reversed. The asymmetry appears primarily controlled by the slab polarity with respect to the westward drift of the lithosphere.