IMPROVEMENTS IN LONG-CORE MEASUREMENT TECHNIQUES - APPLICATIONS IN PALEOMAGNETISM AND PALEOCEANOGRAPHY

We report on new developments in the long-core measurement techniques using u channels in connection with new small-access cryogenic magneto meters. With these new instruments, u-channel samples allow us to meas ure a wide range of magnetic parameters along entire-core length with a spatial resolution and accuracy virtually equivalent to that obtaine d using discrete cubic samples. An additional advantage is that the se diment disturbance when sampling is significantly less when using u ch annels. We present comparisons of results from both continuous and dis crete measurements and examine the effectiveness of minimal deconvolut ion using various techniques. Examples of continuous measurements of l ow-field susceptibility, NRM, ARM, IRM, Hrc from North Atlantic deep-s ea cores show that it is possible to generate logs of combination of p arameters related to rock-magnetic characteristics of the sediments us eful in palaeoceanography. In particular, the continuous method allows us to rapidly detect core regions with fast changing magnetic paramet ers useful for correlation between cores and also for understanding ch anges in palaeo-environmental conditions. The fast scan also allows us to detect regions of the core where the rock magnetic parameters are suitable (or not suitable) for palaeomagnetic studies related to chang es in the geomagnetic field such as the relative changes in palaeointe nsity.