(Table 1) Rock description and nitrogen concentrations and isotopic compositions of altered oceanic crust samples from ODP Hole 185-801C

The basement at Site 801 is divided into 4 intervals (the alkaline basalt sills and 3 MORB sections) according to the geochemical characterization of more than 100 communal samples (Plank et al., 2000; http://www-odp.tamu.edu/publications/185_IR/185ir.htm). For each interval, one composite was made for submarine extrusives (FLO) and clastic rocks (VCL) by combing proportional communal samples. FLO and VCL are then combined into the MIX composite in a ratio of 30-70%. The SUPER composite was made for the entire MORB interval by combing the 3 MORB composites. The SED composite was made for the intercalated sediments in the upper 230 m of the basement (mostly in Sequences I, III, and IV, see descriptions by Plank et al. (2000); http://www-odp.tamu.edu/publications/185_IR/185ir.htm; Alt (2003); doi:10.1029/2002GC000400).