Long-iota VRM and relative paleointensity estimates in sediments

Geomagnetic paleointensity measurements from sedimentary records can be sev erely affected by viscous remanent magnetization (VRM). We present a method for determining varying amounts of long-term VRM acquired during the prese nt polarity interval, using the typically non-linear relationship between a cquisition of artificial magnetization and demagnetization of NRM. The non- linear parts are to be avoided for paleointensity determinations, but here we focus on their use for indicators of long-relaxation time VRM. The metho d, which does not require determining paleointensity values, suggests corre lations with paleoclimate curves and age-dependent growth of VRM. Furthermo re, it appears that the long-tau VRM acquired during the Pleistocene is acc ompanied by short-tau effects detected in the laboratory environment. (C) 1 999 Elsevier Science B.V. All rights reserved.