Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/3937
Authors: Speranza, F.* 
Maniscalco, R.* 
Grasso, M.* 
Title: Pattern of orogenic rotations in central–eastern Sicily: implications for the timing of spreading in the Tyrrhenian Sea
Journal: Journal of the Geological Society, London 
Series/Report no.: 2 / 160 (2003)
Publisher: Geological Society of London
Issue Date: 2003
Keywords: Sicily
Tyrrhenian Sea
Maghrebides
paleomagnetism
plate rotation
Subject Classification04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism 
Abstract: New palaeomagnetic data from upper Triassic to Pliocene sediments reveal that in eastern Sicily a major 70° clockwise (CW) rotation took place between Oligocene and late Tortonian time, followed by a further 30° CW rotation. Results from central Sicily are less coherent. They show 44–83° post-Oligocene CW rotation, local 14° post-late Tortonian counterclockwise (CCW) rotation, and 25° post-mid-Pliocene CW rotation. We interpret the larger CW rotation observed in eastern Sicily as related to a more internal palaeogeographical position with respect to central Sicily. Our results complement pre-existing data from the northwestern Sicily carbonates, and indicate that all the internal carbonate nappes coherently rotated by c. 100° CW during tectonic emplacement, implying a west-to-east increase of shortening in the Sicilian Maghrebian belt. In Sicily, compressive deformation started during the Langhian, i.e. just after the deposition of the upper Oligocene–upper Burdigalian Numidian Flysch turbidites. Therefore the age of the older 70° palaeomagnetic rotation (synchronous to the thrusting) is constrained to occur between the Langhian and late Tortonian. Furthermore, by considering a maximum possible rotation rate of 20° Ma 1, we infer that CW rotation started in Sicily in Langhian–Serravallian times, between 15–16 and 11–12 Ma ago. The 100° CW rotation observed in pre-orogenic strata from the whole of Sicily is mirrored by 80° orogen-scale CCW rotations characterizing the internal southern Apennines. Palaeomagnetism therefore shows that during orogenesis, the southern Apennines and the Sicilian Maghrebides rotated in a 'saloon-door' fashion, synchronous to back-arc spreading of the southern Tyrrhenian Sea. Consequently, our palaeomagnetic data suggest that the southern Tyrrhenian back-arc basin started to spread during Langhian–Serravallian times (from 15–16 to 11–12 Ma), significantly earlier than the late Tortonian age (8 Ma) suggested so far by oceanic drilling data.
Appears in Collections:Article published / in press

Files in This Item:
File Description SizeFormat Existing users please Login
183.pdf604.02 kBAdobe PDF
Show full item record

Page view(s)

115
checked on Mar 27, 2024

Download(s)

26
checked on Mar 27, 2024

Google ScholarTM

Check