HR: 09:05h
AN: GP41B-03    [Abstracts]
TI: Paleomagnetic and Rock Magnetic Results from Sediments from the Adriatic Sea
AU: * Verosub, K L
EM: verosub@geology.ucdavis.edu
AF: Dept. of Geology, University of California-Davis, Davis, CA 95616 United States
AU: Vigliotti, L
EM: luigi.vigliotti@bo.ismar.cnr.it
AF: ISMAR CNR, Via Giobetti 101, Bologna, 40129 Italy
AU: Cattaneo, A
EM: antonio.cattaneo@ifremer.fr
AF: Ifremer-Centre de Brest, Departement Geosciences Marines, Plouzane, 29280 France
AU: Trincardi, F
EM: fabio.trincardi@bo.ismar.cnr.it
AF: ISMAR CNR, Via Giobetti 101, Bologna, 40129 Italy
AB: In the framework of two EC funded project (Eurodelta and Promess-1) we present paleomagnetic and rock-magnetic results from six cores collected in the Adriatic Basin. Four of the cores were collected by using a gravity corer within sequences representing an expanded section of the HST above the maximum flooding surface (KS02-246; CSS00-23 and CSS00-07) or the entire HST extending to the late Glacial-Interglacial transition (AMC99-01). Two long cores were collected by drilling on the Central Adriatic slope and aimed at obtaining 1) a continuous record of sedimentary sequences representing the last four glacial-interglacial cycles extending back approximately 100 kyr (PRAD1-2) and 2) a muddy succession that formed during the last sea-level rise and highstand (PRAD2-4). Paleomagnetic measurements on U-channel samples were carried out at the laboratory of the University of California at Davis using an automated 2G Enterprises cryogenic magnetometer. The NRM measurements from the gravity cores mostly exhibit a declination and inclination pattern characterized by a single paleomagnetic direction whereas a significant magnetic overprint, probably induced by the drilling, has been observed in the long cores. The upward pointing secondary direction associated with the overprint was removed by 10-20 mT of AF demagnetization which allowed us to retrieve the characteristic and primary magnetization of these sediments. The mean, cleaned inclination agrees with the geocentric axial dipole direction for this site. Variations in declination and inclination reveal comparable features during the Holocene and can be compared with secular variation records from other marine and lacustrine cores as well as with lava flows of historical age. These results allow us to develop a detailed age-depth model that will be helpful to reconstruct the history of sedimentation in the time interval under study. Variations in both concentration and grain-size related magnetic parameters reflect changes in sediment supply during the glacial-interglacial stages, as well as changes in environmental conditions, including the formation of sapropel layers.
DE: 1512 Environmental magnetism
DE: 1522 Paleomagnetic secular variation
DE: 3022 Marine sediments--processes and transport
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly