572 resultados para ARM, Intensity after demagnetization
Resumo:
Paleomagnetic studies conducted on board JOIDES Resolution during Leg 119 indicate that the cores collected at Site 744 range from Quaternary through Eocene in age. Initial studies of the sediments completed on board the ship measured the magnetization of the archive halves of the sedimentary cores, using the pass-through cryogenic magnetometer. Stratigraphic plots of the declination and inclination derived from these measurements displayed numerous long intervals with essentially constant magnetic directions. Further study of these intervals led to a discovery that the background signal had been incorrectly computed due to faulty software on the ship. Because this background signal was not recorded in the data-processing system, corrections could not be made. Therefore, subsequent shorebased studies have been made on the individual samples collected at approximately 30-cm intervals in the cores in order to verify the initial magnetostratigraphy reported in the Initial Reports volume for Leg 119 (Barron, Larsen, et al., 1989, doi:10.2973/odp.proc.ir.119.1989). Numerous reversals were identified and correlations were suggested with the seafloor magnetic anomaly sequence of Berggren et al. (1985, doi:10.1130/0016-7606(1985)96<1407:CG>2.0.CO;2) back to anomaly number 17.