• Magnetic rock properties of the gabbros from the ODP Drill Hole 1105 A of the Atlantis Bank, Southwest Indian Ridge

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    • Keywords


      Southwest Indian Ridge; Atlantis Bank; ODP Drill Hole 1105 A; gabbros; serpentinites

    • Abstract


      Laboratory studies of 30 samples from 158 m long drill core of the Hole 1105 A (ODP Leg 179) of the Atlantis Bank, Southwest Indian Ridge have revealed magnetic properties of the gabbros, olivine gabbros, oxide gabbros and olivine oxide gabbros down the core. Comparison of modal proportions of the oxides, grain sizes and magnetization parameters of the rocks has confirmed that most coarse-grained oxide mineral bearing rocks record low Koenigsberger ratio (2 to 5) and median destructive fields (5 to 7 mT). Average natural remanent magnetization (Jnrm) and stable remanent magnetization (Jst) of the core samples are 5.8 A/m and 1.9 A/m, respectively. Their mean stable magnetic inclination is 66‡ ± 4‡, about 14‡ steeper than the expected dipole inclination of the area similar to the one reported at Hole 735 B. The excess inclination perhaps marks a tectonic block rotation of the reversely magnetized rocks of the bank. We interpret that gabbros and serpentinites devoid of basaltic carapace significantly contribute to seafloor spreading anomalies of the bank.

    • Author Affiliations


      D Gopala Rao1 K S Krishna1

      1. National Institute of Oceanography, Dona Paula, Goa - 403 004, India
    • Dates

  • Journal of Earth System Science | News

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      Posted on July 25, 2019

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