Palaeomagnetic Secular Variation Time Constraints on Late Neogene Geological Events in Slope Sediment from the Eastern Tyrrhenian Sea

Cored slope sediment from the Salerno Gulf in the eastern Tyrrhenian Sea ca. 20 km from the Italian coast preserves small-scale changes of Earth's magnetic field behavior (paleomagnetic secular variation; PSV) between 25,000 years B.P. to the present. The age of the cored sediment is calculated from tephrochronology, 14C dates, and correlation to European PSV curves (Turner and Thompson, 1981, 1982; Thouveny et al., 1990) and relative intensity in sediment cored from the Mediterranean Sea (Tric et al., 1992). The analyzed sediments span for the first time the full Holocene and late Pleistocene PSV record in the eastern Tyrrhenian Sea, and results compare well with PSV records for Lac du Bouchet, France (Thouveny et al., 1990). Sedimentation rates, established by PSV dating, are in good overall agreement with sedimentation rates calculated in a second core recovered about 300 m away that was dated by 14C and used for paleoclimate research (Buccheri et al., 2002). However, there are variations in the precision of the dating that depend on the chronologic method used. Moreover, it was found that in the late Pleistocene and to the Pleistocene-Holocene boundary, the sedimentation rate on the continental slope was controlled by global rapid sea-level pulses and cold climatic phases that induced reduction and/or rapid increments in the sediment deposition rate. However, in the middle Holocene during phases of continuous relative sea-level increase, the sedimentation rate on the slope was less sensitive to climatic control than on the continental shelf, whereas from the late Holocene to the present it seems that on both the continental shelf and slope local factors such as volcanic supply and human deforestation could have caused an increase in the sedimentation rate.