Table 7. Composition of the gas collected from whole 1.5-m sections from Sites 991 and 993.												

"Core, section"	Depth (mbsf)	O2 (ppmv)	N2 (ppmv)	C1 (ppmv)	CO2 (ppmv)	C2 (ppmv)	C3 (ppmv)	i-C4 (ppmv)	n-C5 (ppmv)	i-C6 (ppmv)	C1/C2	C1/C2+

164-991A-												
5H-3	40.6	174000	726000	64000	4400	51.8	1.7	0.9	0.8	0.3	1240	1150
6H-2	48.6	129000	742000	100900	4300	91	1.5	0.7	0.6	0.4	1110	1070

164-993A-												
5X-3	35.6	NA	NA	427	1230			NA	NA	NA		
4X-4	27.5	NA	NA	73	910			NA	NA	NA		

"Notes:  Oxygen (O2) and nitrogen (N2) concentrations are included as a guide to the amount of air contamination in each sample. C1 through C6 = the alkanes: methane, ethane, propane, butane, pentane, and hexane."												
"Iso- and normal configurations of butane, pentane, and hexane are designated with i- and n- prefixes. C1/C2 = the methane/ethane ratio and C1/C2+ = the ratio of methane/the sum of (C2 through C6). NA = not analyzed."