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

Journal of Earth system science

K S Krishna1¹  D Gopala Rao1¹ 

[1] National Institute of Oceanography, Dona Paula, Goa 403 004, India.$$

关键词: Southwest Indian Ridge;    Atlantis Bank;    ODP Drill Hole 1105 A;    gabbros;    serpentinites.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Laboratory studies of 30 samples from 158m long drill core of the Hole 1105A (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 5.8A/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.

【 授权许可】

Unknown