TO: Tom Davies
FM: Jay Miller
JA Daily Science Report for Expedition 304, 27 December 2004.
LOCATION: Site U1309 (prospectus site AMFW-01A)
Latitude: 30° 10.1195'N Longitude: 42° 07.1311'W
Water depth: 1645 mbsl
SCIENCE UPDATE: Cores U1309D-50R to -57R (262.0 to 300.4 mbsf, 81% recovery, 60% average recovery for hole). Cores U1309D-50R through -53R are predominantly coarse-grained, moderately greenschist facies altered, olivine gabbro and olivine-bearing gabbro. Although mostly coarse-grained, thin (few tens of cm) intervals are medium coarse-grained. Continuing down section, the core contains oxide gabbro then medium coarse-grained troctolite. A thin interval of gabbro has a sharp contact with dunite that grades into medium- to coarse-grained, modally layered troctolite. There is another sharp contact between troctolite and coarse-grained, olivine-bearing gabbro near the base of the cored interval. Our general impression is that the intensity of alteration continues to diminish down section, and intervals with strong deformational fabrics are rare and localized.