Table 12. Composition of headspace gas in sediment from Site 997.						

"Core, section"	Depth (mbsf)	C1 (ppmv)	C2 (ppmv)	C1/C2	C1 (uL/kg wet sediment)	C2 (uL/kg wet sediment)

164-997A-						
1H-2	1.5	4	0.1	35	22	1
2H-4	7.4	10	0.1	100	37	0
3H-4	16.9	43	0.3	173	139	1
4H-4	26.4	9800	1	9850	31500	3
5H-4	35.9	27300	1.7	16000	89500	6
6H-4	45.4	39000	2.4	16300	93300	6
7H-1	50.4	56200	2.9	19400	180000	9
8H-2	54.4	30400	1.8	16900	98600	6
9H-4	65.9	25300	1.4	18100	76300	4
10H-4	75.25	31700	2.2	14400	96600	7
11H-4	84.9	14000	1.4	10000	44500	4
12H-4	94.4	29700	2.6	11400	91600	8
13H-3	101.48	18000	2	8890	63400	7
14H-5	113.73	20000	2.1	9530	50400	5
15H-5	124.4	16700	2	8370	39400	5
16H-4	132.4	7	0.2	37	21	1
17H-2	138.9	9800	1.6	6110	23400	4
19H-2	148.73	4200	1	4220	16500	4
20H-2	158.9	5300	1.3	4090	18700	5
21X-1	166.9	2600	1.3	2030	8270	4
22X-4	176.72	2900	1.2	2380	8470	4
26X-3	206.4	3100	1.6	1930	6660	3
27X-4	216.5	6600	2.7	2460	18200	7
28X-2	223.1	3900	1.3	3030	12200	4
31X-1	240.9	3700	1.8	2040	10300	5
32X-1	250.5	14700	5.7	2580	27400	11
34X-2	262.6	1600	2.2	736	4750	7
36X-2	279.55	2500	2.4	1050	5570	5
37X-6	296.4	1900	1.4	1380	5980	4
38X-5	304.5	1900	1.4	1340	8440	6
39X-5	314.1	1600	2.7	610	5170	9
41X-4	323.2	8000	5.6	1420	14900	10
42X-2	328.9	4500	2.4	1880	5070	3
43X-1	337	4800	4.9	974	7620	8
44X-4	351.2	5000	3.1	1630	9540	6
46X-4	370.15	5100	5.3	967	7220	7
47X-1	375.6	13400	14.3	940	11100	12
48X-1	385.3	27500	31.1	883	61100	69
50X-1	395.9	3600	5.4	658	16700	25
52X-1	405.5	3800	8	471	12200	26
54X-4	427.88	1100	2.5	457	5090	12

164-997B-						
11X-5	469.2	5100	12.9	392	8620	22
12X-1	471.8	11100	24.2	459	11700	25
13X-2	483	8900	23	386	13000	34
14X-4	495.11	6500	13.5	484	19500	40
16X-4	506.3	5500	14.8	374	20500	55
17X-1	510.4	7200	12.9	561	12600	23
18X-4	524.5	11100	37.5	296	18900	64
19X-3	532.6	200	0.3	597	451	1
20X-3	542.2	2900	10	294	11500	40
22X-4	554.3	2700	9.5	281	8650	30
23X-4	562.9	2400	9.1	268	7830	30
24X-3	571	4400	20	221	11100	50
26X-2	580.1	6200	19	328	23300	71
27X-4	591.7	3700	14.9	249	12400	50
28X-4	600.57	9300	27.6	338	15900	47
29X-3	609.5	5700	20.8	274	19600	71
30X-2	617.6	8700	37.2	234	15100	64
31X-4	630.13	9800	34.7	283	16900	60
33X-4	639.97	10300	59.8	172	12900	75
34X-1	644.9	7800	42	186	10800	58
35X-3	656.27	6200	17.5	352	12100	34
37X-3	668.1	10700	47.7	225	31100	139
38X-4	678.3	9200	44	209	23400	112
39X-6	690.9	5500	29.3	188	15300	82
41X-1	694	2100	11	193	3790	20
42X-3	704.67	2100	10.3	202	6370	31
43X-2	713.7	5800	49.6	117	12800	110
45X-3	725.8	9600	87.7	109	13600	124
46X-3	733.24	6700	20.2	331	6210	19
47X-3	744.1	14000	109.8	128	19300	151

"Notes: C1 through C6 = the alkanes: methane, ethane, propane, butane, pentane, and hexane. C1/C2 = the methane/ethane ratio, and C1/C2+ = the ratio of methane/the sume of (C2 through C6)."