Magnetic properties of gabbros from Hole 735B, Southwest Indian Ridge

Abstract

Many of these gabbros, which are mainly Fe-Ti oxide gabbros, have strong and unstable secondary magnetic components that were acquired during drilling. Stable inclinations which are probably in-situ magnetic directions, show a single polarity, with an average value of 66°(±5°), meaning that the studied 501-m oceanic gabbroic block may be a candidate for the source of the marine magnetic anomaly. The oceanic gabbros probably record the so-called Vine-Matthews-Morley type of initial magnetization at the ridge. If magnetic properties of the samples obtained from Hole 735B are common to oceanic gabbros, layer 3 may contribute more significantly to seafloor spreading magnetic anomalies than previously thought. -from Authors