TO: Tom Davies

FM: Jay Miller


JA Daily Science Report for Expedition 305, 20 January 2005.


SCIENCE UPDATE: Cores 305-U1309D-104R to -107R (515.8 to 535.0 mbsf, 82% recovery) are intercalated coarse-grained gabbro and olivine-bearing gabbro with medium-coarse grained olivine gabbro. Many contacts are sharp, but gradational transitions between lithologies are not uncommon. Modal mineralogy (generally abundance of olivine and clinopyroxene) can vary over a few centimeters, even in intervals characterized as an individual lithologic unit. Alteration is generally slight to moderate (commonly less than 20%, with some intervals as much as 50% altered). Magmatic fabric is subtle and indicators of strain are rare to nonexistent throughout this cored interval.