georefid:2003-029418SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2003-0294182002-01-01publicationgeorefid:2003-029418Gopala Rao, D.National Institute of Oceanography, Goa, IndiaauthorKrishna, K. S.authorIndian Academy of Sciences, Bangalore, IndiapublisherdocumentHardcopyProceedings of the Indian Academy of Sciences: Earth and Planetary Sciences111 (4)467-481Laboratory 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.completedGeneral geophysicscoresgabbrosigneous rocksIndian OceanLeg 118Leg 176Leg 179magnetic inclinationmagnetic propertiesmagnetizationmetaigneous rocksmetamorphic rocksmetasomatic rocksnatural remanent magnetizationOcean Drilling ProgramODP Site 1105ODP Site 735paleomagnetismplutonic rocksremanent magnetizationserpentiniteSouthwest Indian Ridgeurn:org.iodp:exp:118urnlargerWorkCitationcampaignurn:org.iodp:exp:176urnlargerWorkCitationcampaignurn:org.iodp:exp:179urnlargerWorkCitationcampaignurn:org.iodp:exp:179:site:1105urnlargerWorkCitationstudyurn:org.iodp:exp:179urnlargerWorkCitationcampaignurn:org.iodp:exp:118:site:735urnlargerWorkCitationstudyurn:org.iodp:exp:118urnlargerWorkCitationcampaignurn:org.iodp:exp:176:site:735urnlargerWorkCitationstudyurn:org.iodp:exp:176urnlargerWorkCitationcampaignEnglishgeoscientificInformation57.163957.1639-32.4308-32.4308