Latest Miocene to Quaternary horizontal and vertical displacement rates during simultaneous contraction and extension in the Southern Apennines orogen, Italy Luigi Ferranti 1 and John S. Oldow 2 1 Dipartimento di Scienze della Terra, Universita ` Federico II, 80138 Napoli, Italy; 2 Department of Geological Sciences, University of Idaho, Moscow, ID 83844, USA Introduction Since conceptualization of episodic mountain building (Stille, 1924) and revision to a more steady-state view engendered by plate tectonics (Gilluly, 1973), documentation of orogenic dis- placement rates and how they vary over geological time have proven dif- ficult to evaluate. In Italy, the South- ern Apennines orogen provides an unusual opportunity to compare hori- zontal and vertical displacement rates over a period of 6 Myr. The South- ern Apennines experienced late Ceno- zoic foreland contraction and hinterland extension (Patacca et al., 1990; Doglioni, 1991) recorded by the surface and subsurface distribution of well-dated latest Miocene to Pleisto- cene synorogenic rocks. Together with the differential uplift of ancient base- level markers, a regional pattern of horizontal and vertical displacement emerges and points to an intricate interplay between lithospheric delam- ination and crustal structure. Regional tectonic setting In southern Italy, Neogene deforma- tion evolved during collision between ABSTRACT Foreland contraction and hinterland extension in the Southern Apennines orogen of Italy produced a complex spatial and temporal pattern of vertical and horizontal displacement. Remarkably, Late Miocene to mid-Pleistocene foreland migra- tion of the contractional front at 16 mm yr -1 was not accompanied by uplift and the frontal thrust belt remained at or below sea level. Only following a mid-Pleistocene reduction in horizontal displacement did the frontal thrust belt and foreland begin uplift at 0.5 mm yr -1 , a rate that increased to 1 mm yr -1 after 125 ka. Although the extensional hinterland experienced net subsidence during formation of the Tyrrhenian basin, an extensional transition zone adjacent to the frontal thrust belt records sustained uplift at 0.3 mm yr -1 . The interaction of preexisting crustal structure and deep tectonic processes resulted in time-integrated displacement rates sug- gesting steady-state deformation for periods of 10 6 years. Displacement rate changes were abrupt and occurred over intervals of 10 5 years or less. Terra Nova, 17, 209–214, 2005 Fig. 1 Map of the Southern Apennines showing tectonic belts, distribution of piggy- back basins in the frontal belt (OB, Ofanto basin), vertical markers of displacement, location of the thrust front, and the Quaternary (and mainly active) normal faults. Wells: Ac, Acerno; Sg, San Gregorio; Cc, Ciccone; Ma, Maschito; Rn, Rendina. Correspondence: Luigi Ferranti, Diparti- mento di Scienze della Terra, Universita` Federico II, 80138 Napoli, Italy. Tel.: +39-81-2538100; fax: +39-81-5525611; e-mail: luigi.ferranti@unina.it Ó 2005 Blackwell Publishing Ltd 209 doi: 10.1111/j.1365-3121.2005.00593.x