JA Daily Science Report for Expedition 309, 04 August 2005


LOCATION: Site 1256


SCIENCE UPDATE: Hump day was celebrated with the arrival, shortly after the stoke of midnight, of Core 122R. This core contains numerous semi-contiguous pieces of a spectacular sulfide-quartz-clay-carbonate cemented hyaloclastite breccia with common cm-scale, highly altered basaltic clasts. A 1 to 4 cm-thick vertical quartz-sulfide vein, cross-cutting basaltic breccia, occurs in Pieces 9 to 11 of Section 122R-2 immediately below the hyaloclastite breccia. Core 122R recovered 2.23 m from 1027.3 to 1032.1 mbsf (46.5%). Cores 123R to 126R recovered 3.81 m of aphyric to sparsely phyric, cryptocrystalline to fine-grained, slightly altered dark grey basalt from 1032.1 to 1051.30 mbsf (19.8%). After Core 126R was retrieved the bit had accumulated 50.1 hours of rotation and the pipe was tripped for a bit change. CC-9 RCB Bit #5 achieved a penetration of 72.1 m at an average rate of 1.44 m/hr.  This hiatus in coring has allowed the science party respite in their scouring of the core for signs of dikes and greenschist facies alteration.