TO: Tom Davies

FM: Jay Miller


JA Daily Science Report for Expedition 305, 25 January 2005.


SCIENCE UPDATE: Cores 305-U1309D-136R to -142R (669.4 to 703.0 mbsf, 82% recovery) are predominantly gabbroic, but there are some astounding textures and lithologic variability in this cored interval. The top of the interval recovered plagioclase-bearing wehrlite, including sharp contacts with cataclastic, coarse-grained gabbro. A subvertical, sheared intrusion of fine-grained oxide gabbro meanders through more than 3 m of core, entraining pieces of the gabbroic wall rock and exhibiting high-temperature deformation. Beneath the oxide gabbro, coarse-grained gabbro  overlies an 8-m-thick section of medium- to coarse-grained oxide-bearing gabbro. The lower 10 m of the cored interval recovered medium- to coarse-grained gabbro with intervals of olivine-bearing gabbro.