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

Autor: D. Gopala Rao, K. S. Krishna
Rok vydání: 2002
Předmět:
Zdroj: Journal of Earth System Science. 111:467-481
ISSN: 0973-774X
0253-4126
Popis: 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 conrmed that most coarse-grained oxide mineral bearing rocks record low Koenigsberger ratio (2 to 5) and median destructive elds (5 to 7mT). Average natural remanent magnetization (Jnrm) and stable remanent magnetization (Jst) of the core samples are 5.8A/m and 1.9A/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 signicantly contribute to seafloor spreading anomalies of the bank.
Databáze: OpenAIRE
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