JA Daily Science Report for Expedition 312, 11 December 2005


LOCATION: Site 1256


SCIENCE UPDATE: Core 209R recovered four roughly hewn moderately altered basaltic stones (15 cm) from 1396.5 to 1398.6 mbsf representing an average recovery of 7.1%. At 0500 hr the bit had accumulated 45.1 hr of rotation so the pipe was tripped for a bit change. Thin section observations have revealed that significant proportions of the basalts from the last several cores are thoroughly recrystallized to microcrystalline, granular aggregates of secondary clinopyroxene, orthopyroxene, hornblende, and secondary plagioclase, with sub-rounded blebs of magnetite and ilmenite. There is consensus that there must have been significant reheating of these rocks but the origin of these meta-basaltic assemblages continues to be debated. Whether these equigranular patches are the harbinger of plutonism will only be proven by our unshaken resolve to penetrate deeper.