Rock magnetic studies of serpentinite seamounts in the Mariana and Izu-Bonin regions

Abstract

Grain densities of the serpentinized peridotites range from 2.44 to 3.02 g/cm3. The NRM intensity of the serpentinized peridotites ranges from 0.01 to 0.59 A/m and that of serpentine sediments ranges from 0.01 to 0.43 A/m. Volume susceptibilities of serpentinized peridotites range from 0.05 × 10-3 SI to 9.78 × 10 -3 SI and from 0.12 × 10-3 to 4.34 × 10-3 SI in the sediments. Koenigsberger ratios vary from 0.09 to 80.93 in the serpentinites and from 0.06 to 4.74 in the sediments. The AF demagnetization behavior of the serpentinized peridotites shows that a single component of remanence can be isolated in many samples that have a median destructive field less than 9.5 mT. Comparison of the AF demagnetization of saturation isothermal remanence and NRM suggests that the serpentinized peridotites contain both single-domain and multidomain magnetite particles. The variability of the magnetic properties of serpentinized peridotites reflects the complexity of magnetization acquired during serpentinization. -from Authors