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IODP Expedition 330 Louisville Seamount Trail

Daily Science Report 12 -- Thursday, 23 December 2010


Site U1372 on 26.5°S Guyot 26° 29' 35.9988" S, 174° 43' 45.0012" W
Louisville Seamount Trail
0 m above sea level

Cores U1372A-6R (23.5-32.8 mbsf), U1372A-7R (32.8-42.1 mbsf), and U1372A-8R (42.1-51.7 mbsf) recovered more of the colorful volcaniclastic, carbonate-cemented breccia with exceptional recovery rates of 50%, 79% and 89% respectively. The breccias include large intervals (boulder-size) of surprisingly well-preserved volcanic rock some of which contain abundant fresh olivine crystals. This discovery was greeted with great delight, as fresh olivine can be used for a range of petrological and geochemical investigations. These include assessments of temperature and He isotopic composition of the magma source (which were never done for Louisville before due to a lack of suitable olivine in the hitherto available dredge samples). All descriptive lab groups are busy describing the recovered rocks. The paleomagnetism group is applying the “conglomerate test” to all vertically oriented pieces by measuring their magnetic orientation to identify the relative timing of magnetization and deposition of the clastic succession. At noon, the first 12:00 sampling meeting was held, were the recovered rocks where briefly discussed and the exact location of samples taken for ship-board studies (e.g. thin sections, geochemistry, physical properties etc.) were identified.