Chronology of the transition from a spreading ridge to an accretional seamount in the Marsili backarc basin (Tyrrhenian Sea) |
| |
| Authors: | L Cocchi F Caratori Tontini F Muccini M P Marani G Bortoluzzi C Carmisciano |
| |
| Institution: | Istituto Nazionale di Geofisica e Vulcanologia, Via Pezzino Basso 2, 19025, Fezzano, Italy;;Universitàdi Bologna, Dipartimento di Scienze della Terra e Geologico –Ambientali, Piazza Porta S. Donato 1, 40125 Bologna, Italy;;ISMAR-CNR, Sezione di Geologia Marina, Via Gobetti 101, 40129 Bologna, Italy |
| |
| Abstract: | Inversion of new high-resolution magnetic data from the Marsili seamount and the surrounding basin in the Tyrrhenian Sea reveals NNE–SSW magnetization stripes ranging from the Matuyama chron to the Brunhes chron, including the short positive Jaramillo subchron. The detailed magnetic chronology shows that from the late Matuyama (1.77 Ma), the average half spreading rate was about 1.5 cm yr?1, with a slight decrease between the Jaramillo and the Brunhes events, when the growth of the volcanic edifice overcame lateral spreading. Analysis of spreading rate and volume of erupted lava indicates that at the beginning of the Jaramillo subchron (1.07 Ma), the Marsili basin evolved from pure horizontal spreading to a superinflated seamount as a consequence of tearing of the Ionian slab. Our data give us a snapshot of the geodynamic transition from an active backarc spreading phase to the vertical accretion of the seafloor because of a radical change in the subduction dynamics. |
| |
| Keywords: | |
|
|
