JA Daily Science Report for Expedition 309, 02 August 2005 


LOCATION: Site 1256 


SCIENCE UPDATE: Cores 112R to 116R recovered 7.41 m of basalt over 24 m of penetration representing 30.9% recovery from 979.20 to 1003.2 mbsf. Penetration rates continue to average a grueling ~1 m/hr.  The rocks are cryptocrystalline to fine grained, aphyric to sparsely phyric, basalt sheet flows and are sub-divided into 3 igneous units. The continued presence of quenched glassy margins and vesicles indicates that these rocks are eruptive as opposed to intrusive. Portions of Core 114R are highly vesicular. Saponite remains the dominant secondary mineral but it is accompanied by abundant pyrite in veins, along quenched glassy margins, and as irregular mm-scale clots disseminated throughout the fine-grained flow groundmass.