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IODP Expedition 330 Louisville Seamount Trail

Daily Science Report 50 -- Sunday, 30 January 2011


Site U1376 on Guyot 32.3°S 32° 12' 59.4" S, 171° 52' 50.4012" W
Louisville Seamount Trail
0 m above sea level

Cores U1376A-8R to -10R (67.0 to 86.8 mbsf) were received with 90% recovery. The high recovery is particularly incredible since most of the cored interval is composed of massive fresh igneous rock. Core U1376A-8R recovered more of the fragmented moderately olivine- and pyroxene-phyric lava breccia within a hyaloclastite matrix. The breccia transitions downhole into a massive (>14 m thick) lava flow comprising the lower half of Core U1376A-8R and continuing throughout Core -10R. The rock is highly olivine-augite phyric and the olivine crystals are very well presevered which makes them well suitable for all kinds of geochemical studies. The ongoing investigation of macrofossil fragments found in the algae reef carbonates above the breccia indicates a Cretaceous age for the igneous succession drilled at this site. Since the drill bit had accumulated 72.4 hours of rotation it was decided to exchange the bit, although the hard rock nature of the seafloor would not support the deployment of a free fall funnel (which usually guides re-entry). After a camera survey it was concluded that direct re-entry might be feasible and preparations started in the late afternoon.