JA Daily Science Report for Expedition 309, 18 August 2005


LOCATION: Site 1256


SCIENCE UPDATE: Cores 162R to 164R recovered 10.28 m of aphyric cryptocrystalline to microcrystalline basalt from 1213.4 to 1227.8 mbsf (71.4 % recovery) that is divided into five units (56A, 57A, 58, 59, and 60A) based on grain size increase from the top of the units. Basalts in Units 56A and 57A are intruded by basaltic dikes (Units 56B and 57B) with sharp to irregular and/or brecciated glassy to cryptocrystalline chilled margins. The breccias consist of acicular to subrounded cryptocrystalline basalt clasts and altered glass fragments cemented by chlorite. Section 163R-1, Piece 14 (57A) has an intricate and irregular dike (57B) contact indicating intrusion at hypersolidus temperatures.