TO: Tom Davies
FM: Jay Miller
JA Daily Science Report for Expedition 305, 4 February 2005.
SCIENCE UPDATE: Cores 305-U1309D-179R to -184R (871.0 to 899.8 mbsf, 83% recovery) are predominantly coarse-grained gabbro, with intervals of medium-grained gabbro. Most grain size transitions are sharp and dipping, but attitude of dip is variable from steep to subhorizontal. A basaltic dike with a sharp, undulose contact intruded medium-grained gabbro in the upper part of the cored interval. Below the dike, a few irregular patches of oxide gabbro are within a coarse-grained gabbro. The middle of the cored interval recovered a few m thick, varitextured, medium- to coarse-grained oxide gabbro, exhibiting a range of deformation intensities. The lower part of the cored interval is coarse-grained gabbro with rare olivine-rich intervals.