TO: Tom Davies
FM: Trevor Williams
JA Daily Science Report for Expedition 307, 3 May 2005
LOCATION: Site U1317 (PORC-3A)
Cores U1317A-2H to 16H (6.5-130.8 mbsf, >100% recovery) and U1317B-1H to 9H (0-81.5 mbsf, >100% recovery) are coral-bearing floatstone, which shows alternation of light-green calcareous layers and darker less calcareous layers. Cores U1317A-17X and 18X (130.8-137.95 mbsf) are green-grey siltstone. For cores U1317A-2H to 16H, preliminary nannofossil biostratigraphy indicates late Miocene/early Pliocene to early Pleistocene ages.
From headspace gas analysis, methane is very low (1.8-2.4 ppm) in the coral-bearing floatstone (0-130.8 mbsf), and varies irregularly between 30-575 ppm in the green-grey siltstone (130.8-137.95 mbsf). Ethane is absent except for trace quantities below 130.8mbsf . Sulfate decreases with depth fairly linearly from 26 mmol/l to 5 mmol/l