Gopala Rao, D. and Krishna, K. S. (2002): Magnetic rock properties of the gabbros from the ODP Drill Hole 1105 A of the Atlantis Bank, southwest Indian Ridge

Leg/Site/Hole:
ODP 118
ODP 176
ODP 179
ODP 179 1105
ODP 118 735
ODP 176 735
Identifier:
2003-029418
georefid

Creator:
Gopala Rao, D.
National Institute of Oceanography, Goa, India
author

Krishna, K. S.
author

Identification:
Magnetic rock properties of the gabbros from the ODP Drill Hole 1105 A of the Atlantis Bank, southwest Indian Ridge
2002
Proceedings of the Indian Academy of Sciences: Earth and Planetary Sciences
Indian Academy of Sciences, Bangalore, India
111
4
467-481
Laboratory studies of 30 samples from 158 m long drill core of the Hold 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 (J (sub nrm) ) and stable remanent magnetization (J (sub st) ) of the core samples are 5.8 A/m and 1.9 A/m, respectively. Their mean stable magnetic inclination is 66 degrees + or -4 degrees , about 14 degrees 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.
English
Serial
Coverage:Geographic coordinates:
North:-32.4308
West:57.1639East: 57.1639
South:-32.4308

General geophysics; cores; gabbros; igneous rocks; Indian Ocean; Leg 118; Leg 176; Leg 179; magnetic inclination; magnetic properties; magnetization; metaigneous rocks; metamorphic rocks; metasomatic rocks; natural remanent magnetization; Ocean Drilling Program; ODP Site 1105; ODP Site 735; paleomagnetism; plutonic rocks; remanent magnetization; serpentinite; Southwest Indian Ridge;

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