32. PALEOMAGNETISM OF BASALTS AND INTERLAYERED SEDIMENTS DRILLED DURING DSDP LEG 49 (N-S TRANSECT OF THE NORTHERN MID-ATLANTIC RIDGE)

• Main Author: A. M. Faller
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Mid-Atlantic Ridge; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.601.4623; http://www.deepseadrilling.org/49/volume/dsdp49_32.pdf

We report paleomagnetic results for Leg 49 obtained onboard Glomar Challenger and subsequently in the shore laboratories. The intensity of remanent magnetization of basaltic ocean crust fluctuates with depth at all sites; within-site variation of this property exceeds between-site variation. No significant differences in the remanence intensity of the upper ocean crust occur between magnetic anomalies 13 and 2 ' or between groups of sites at latitudes 37°N, 45°N, and 63°N. An arithmetic mean intensity of 5.0 × 10~3 emu/cm3 for all Leg 49 basalt specimens is close to previous average values for samples from the North Atlantic Ocean floor. Median destructive fields, weak field susceptibilities, and Königsberger ratios are comparable with previous results from ocean floor basalts. The Königsberger ratios show that remanence dominates the magnetization of the upper ocean crust. In seven out of eight holes, the sign of the stable inclination is appropriate to the magnetic anomaly. Values of stable inclination fluctuate with depth. At two sites, abrupt changes in stable inclination together with other paleomagnetic properties make it easy to define distinct magnetic units. At the other sites, it is more difficult to locate boundaries using magnetic evidence alone. Fewer magnetic units than petrographic units are identified in all cases.