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IODP Expedition 330 Louisville Seamount Trail

Daily Science Report 13 -- Friday, 24 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-9R (51.7-61.3 mbsf), -10R (61.3-70.9 mbsf), -11R (70.9-80.5 mbsf) and -12R (80.5-90.1 mbsf) were retrieved with an exceptional high average recovery rate of 76%. With the identification of the first “in situ” lava flow in Core U1372-8R, the top of the igneous basement is defined at 45.6 mbsf (just about 10 m shallower then expected based on seismic data). All subsequent cores U1372A-9R to -12R returned more lava flows and hence confirmed this interpretation. However, Core U1372A-9R shows evidence for mixture or shallow intrusion of lava into unconsolidated sediment and is therefore interpreted as peperite. Subsequent cores (beginning in Section U1372A-10R-2 and below) show almost textbook-like examples of lava flow successions with rubbly, autobrecciated, vesicle-rich, and highly altered top and bottom zones and massive, less altered to fresh interior parts. Some of these flows contain abundant olivine phenocrystals that show nice transitions from completely altered (exterior flow parts) to very fresh (interior flow parts) sometimes within a single piece of core material over intervals of just a few centimeters. Everyone on board is awaiting the arrival of Santa Claus in the coming morning and is hoping for many presents in the form of continued recovery of many, well-preserved lava flows.