Table 9. Composition of headspace gas in sediment from Hole 994C. "Core, section" Depth (mbsf) C1 (ppmv) C2 (ppmv) C3 (ppmv) C1/C2 C1/C2+ C1 (uL/kg wet sediment) 164-994C- 2H-4 8.9 11 40 3H-4 18.4 1950 0.5 3900 6050 4H-7 32 26000 2 13000 13000 68700 5H-2 35.85 13900 0.9 15400 52700 6H-3 46.55 29200 2 14600 86100 7H-5 57.9 23400 1 23400 23400 78500 8H-4 65.9 25800 2 12900 12900 90700 10H-5 77.9 14500 1.2 1 12100 6600 42000 11H-4 85.9 17400 1 17400 17400 38900 12H-4 95.4 12000 41000 13H-4 104.9 11200 1.3 8630 25700 14H-4 114.4 17000 1.4 12200 43700 15H-4 123.26 348 1030 16H-5 134.9 7150 1.3 5500 16700 17H-3 141.4 14000 1.3 10700 35000 20X-5 164.4 4730 0.9 0.9 5150 2720 13800 21X-5 170.8 14800 1 1.2 14800 6720 77200 22X-6 180.9 4940 1 1.2 4940 2250 21100 23X-4 188.5 23200 2.5 1.1 9270 6440 107700 24X-3 196.6 7080 1 7080 7080 33000 25X-5 209.3 9280 2.4 3870 3870 37500 26X-3 215.9 3230 0.9 0.7 3590 2020 14900 30X-2 243.2 5030 2 2520 2520 19900 31X-5 257.3 6730 2 3370 3370 28500 32X-1 260.9 1400 1 1400 1400 9130 33X-3 273.39 4400 1.4 0.8 3140 1970 20400 35X-2 290.46 3140 1.2 0.4 2620 2000 11600 38X-2 310.5 3000 1.7 1.3 1760 999 12500 39X-1 318.6 1280 1 1 1280 640 7190 40X-3 331.3 2080 2 1 1040 693 11500 41X-2 339.4 3800 4.4 1.3 862 665 11500 42X-3 350.6 174 0.2 757 757 650 43X-3 359.68 4020 2.2 1.1 1830 1220 16700 44X-2 368.3 4560 2 1 2280 1520 24100 46X-3 379.51 941 1.1 0.6 855 254 7500 47X-4 390.6 516 1 1 516 258 2900 49X-5 401.32 528 0.3 1 2110 422 4200 50X-2 406.7 2510 1 0.7 2510 1470 10300 51X-2 416.3 3370 5 1 675 562 15900 52X-2 426 2830 6 1 472 405 13200 54X-4 439.6 3560 6 1 593 508 10100 55X-2 444.81 2780 5 2 556 397 11200 56X-2 454.9 2920 5.4 2.1 541 389 7050 57X-1 463 3850 4.2 1.5 917 676 17200 58X-1 472.6 2410 3 1 802 602 17900 59X-1 482.3 1230 3 1 410 308 6110 61X-4 497.4 2020 4 1 506 405 11700 62X-3 504.5 672 2 1 336 224 3790 65X-6 530.4 2650 7 3 378 265 14600 67X-4 545.45 4530 11 3 412 324 15600 68X-2 550.3 2390 4 1 597 477 10300 69X-4 563.71 2190 7 3 313 219 5100 71X-4 574.55 5590 12 3 499 399 19400 72X-2 580 1630 5 2 327 233 6020 73X-2 589.6 1010 2.3 0.4 447 380 4390 74X-4 601.04 12000 10.6 2.2 1140 942 74000 75X-4 611.7 546 2 0.6 273 214 1130 76X-4 621.5 1500 5.8 2 259 193 2650 77X-4 630.09 2450 10.5 3.7 233 172 4020 78X-2 637.7 3320 8 2 415 332 6580 79X-2 646.88 7230 37 13 195 145 15200 80X-5 660.41 5750 13 3 442 360 11300 81X-1 665 1510 5 2.1 301 212 4940 82X-1 674.6 1710 12 4.4 142 104 5120 83X-3 686.68 3480 17 5 205 158 7150 84X-3 696.8 32600 44 6 742 653 84300 "Notes: 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, C1/C2+ = the ratio of methane/the sum of (C2 through C6)."