JA Daily Science Report for Expedition 312, 12 December 2005


LOCATION: Site 1256


SCIENCE UPDATE: Cores 210R to 212R recovered 30 cm of moderately altered basalts from 1398.6 to 1406.1 mbsf. After nothing was recovered in Core 210R, recovery jumped from two flat pieces in Core 211R to 27 cm in Core 212R consisting of cryptocrystalline to fine grained basaltic dike rocks displaying a patchy metamorphic overprint. Thin sections of samples from yesterday’s cores reveal a continuing increase in the occurrence of high-temperature metamorphic clino- and ortho-pyroxenes. Lively debate continues regarding the magnitude of the temperatures and the reaction paths leading to these assemblages. At the bottom of Core 212R, virtue finally received a small reward in the form of a pair of ~1 cm-thick quartz diorite dikes.