Journal of the Geological Society; January 2008; v. 165; no. 1;
p. 105-114; DOI: 10.1144/0016-76492007-004
© 2008 Geological Society of London
Pliocene crustal shortening on the Tyrrhenian side of the northern Apennines: evidence from the Gavorrano antiform (southern Tuscany, Italy)
Giovanni Musumeci1,
Francesco Mazzarini2 and
Marco Barsella1
1 Dipartimento di Scienze della Terra, Università di Pisa, Via S. Maria, 53, Pisa 56126, Italy (e-mail: gm{at}dst.unipi.it)
2 Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Pisa, Pisa, Italy
The northern Tyrrhenian Sea and the inner northern Apennines are classically regarded as a late Miocene–Pleistocene back-arc system developed as a consequence of slab rollback along active subduction zones. We present new geological and structural data on the Gavorrano antiform, a key sector of the inner northern Apennines. Lying close to the northern Tyrrhenian Sea, it provides clear evidence of Pliocene shortening deformation and magma emplacement. The orientation of
1 (N50°E–N80°E) derived by fault slip data inversion is consistent with a general ENE–WSW shortening direction. Furthermore, this ENE–WSW-trending orientation of
1 is compatible with the compressive deformation recorded in coeval sedimentary basins. On this basis we suggest that the inner northern Apennines were affected by crustal shortening during the Pliocene. This scenario matches well geophysical data suggesting that since the Late Messinian (6–5 Ma) subduction rollback and back-arc extension strongly decreased in the northern Tyrrhenian Sea, whereas they continued as active processes in the southern Tyrrhenian Sea.
Copyright © 2009 by Geological Society of London