Table T18. Headspace analyses of interstitial and microbial gases, Site 1258.
Hole, core, section,
interval (cm)
Depth
(mbsf)
Routine safety monitoring
Microbial study
C1
(ppmv)
C2
(ppmv)
C2=
(ppmv)
C3
(ppmv)
C1/C2
C1
(ppmv)
C2
(ppmv)
C2=
(ppmv)
C3
(ppmv)
C1/C2
207-










Unit I (nannofossil ooze):








1258A-1R-3, 0–5 3.0 2 0 0 0
7 0 0 0
Unit II (nannofossil chalk):








1258A-2R-3, 0–5 8.1 2 0 0 0
4 0 0 0
1258A-3R-5, 0–5 20.2 2 0 0 0
9 2 0 0 5
1258A-4R-4, 0–5 28.3 2 0 0 0
9 1 0 0 10
1258A-5R-3, 0–5 36.2 2 0 0 0
9 0 0 0
1258A-6R-5, 0–5 48.8 2 0 0 0
4 0 0 0
1258A-7R-4, 0–5 56.7 2 0 0 0
4 0 0 0
1258A-8R-4, 0–5 66.7 2 0 0 0
5 0 0 0
1258A-9R-4, 0–5 76.4 2 0 0 0
3 0 0 0
1258A-10R-4, 0–5 86.1 2 0 0 0
4 0 0 0
1258A-11R-4, 0–5 95.8 2 0 0 0
4 0 0 0
1258A-12R-4, 0–5 105.4 2 0 0 0
3 0 0 0
1258A-13R-4, 0–5 115.0 2 0 0 0
4 0 0 0
1258A-14R-3, 0–5 123.1 2 0 0 0
3 0 0 0
1258A-15R-3, 0–5 132.7 2 0 0 0
27 2 0 0 11
1258A-16R-4, 0–5 143.9 2 0 0 0
9 1 0 0 7
1258A-17R-5, 0–5 155.1 2 0 0 0
7 0 0 0
1258A-18R-4, 0–5 163.2 2 0 0 0
9 0 0 0
1258A-19R-6, 145–150 176.5 14 0 0 0
476 1 0 0 512
1258A-20R-4, 0–5 182.6 12 0 0 0
309 1 0 0 573
1258B-20R-3, 145–150 190.2 58 0 0 0





1258A-21R-3, 0–5 190.7 43 0 0 0
566 1 0 0 682
1258B-21R-2, 142–147 197.9 260 0 0 0





1258A-22R-4, 0–5 201.6 27 0 0 0
865 1 0 0 848
1258B-22R-2, 0–5 206.2 305 0 0 0





1258A-23R-3, 0–5 209.7 16 0 0 0
1,395 1 0 0 1,018
1258B-23R-4, 0–5 218.9 969 1 0 0 969




1258A-24R-4, 0–5 220.8 70 0 0 0
1,367 1 0 0 1,059
1258B-24R-4, 0–5 228.6 2,257 2 0 0 1,026




1258A-25R-4, 0–5 230.5 52 0 0 0
1,802 2 0 0 969
1258B-25R-4, 0–4 238.2 2,016 2 0 0 1,120




1258A-26R-3, 0–5 238.6 205 0 0 0
2,375 2 0 0 1,011
1258A-27R-3, 0–5 248.3 5,843 4 0 0 1,328




1258B-27R-1, 79–84 253.7 1,747 2 0 0 1,165




1258B-28R-1, 0–5 258.6 1,642 2 0 0 966




1258A-28R-6, 0–5 262.4 2,187 2 0 0 1,151 3,940 4 0 0 978
1258B-29R-2, 0–5 264.1 5,063 4 0 0 1,235




1258A-29R-4, 0–5 269.1 3,468 3 0 0 1,196 7,920 7 0 0 1,120
1258B-30R-4, 0–5 276.7 8,102 6 0 0 1,350




1258A-30R-3, 0–5 277.2 2,800 2 0 0 1,167 5,255 5 0 0 1,095
1258B-31R-4, 0–5 286.4 2,376 2

1,212




1258A-31R-5, 0–5 289.9 1,354 1 0 0 1,042 913 1 0 0 748
1258B-32R-4, 0–5 296.0 1,687 1 0 0 1,205




1258A-32R-5, 0–5 299.5 1,733 2 0 0 1,083 1,205 1 0 0 874
1258B-33R-4, 0–5 305.6 2,473 3 0 0 989




1258A-33R-5, 0–5 309.1 7,075 6 0 0 1,160 3,972 4 0 0 937
1258B-34R-4, 0–5 315.3 1,212 1 0 0 1,212




1258A-34R-4, 0–5 317.3 6,428 5 0 0 1,312 5,521 5 0 0 1,148
1258B-35R-1, 0–5 320.4 7,541 6 0 0 1,236




Unit III (clayey nannofossil chalk):








1258A-35R-4, 0–5 326.9 5,656 5 0 0 1,257 5,257 4 0 0 1,173
1258B-36R-2, 0–5 331.6 5,792 5 0 0 1,158




1258A-36R-5, 0–5 338.0 6,975 5 0 0 1,316 6,546 6 0 0 1,068
1258A-37R-3, 0–5 344.7 4,481 4 0 0 1,179 4,056 4 0 0 1,136
1258B-38R-2, 0–5 350.8 6,548 5 0 0 1,423




1258A-38R-3, 0–5 354.3 6,928 5 0 0 1,307 17,652 14 0 0 1,227
1258A-39R-2, 0–5 361.6 6,938 10 0 0 680 3,048 4 0 0 826
1258B-39R-4, 0–5 363.5 9,047 8 0 0 1,190




1258B-40R-1, 75–80 369.4 14,787 11 0 0 1,309




1258A-40R-3, 0–5 373.5 7,569 6 0 0 1,261




1258A-41R-3, 0–5 383.2 8,987 7 0 0 1,302 5,094 4 0 0 1,396
1258B-42R-2, 0–5 385.1 5,275 5 0 0 1,147




1258C-14R-3, 0–5 387.7 7,925 7 0 0 1,116




1258B-43R-2, 0–5 389.3 8,208 6 0 0 1,391




1258C-15R-2, 0–5 391.3 10,113 8 0 0 1,331




Unit IV (laminated black shale):








1258A-42R-3, 0–5 392.7 43,309 133 0 7 326 46,956 131 1 8 358
1258C-16R-1, 145–150 395.9 41,727 137 0 4 305




1258B-44R-3, 132–138 396.7 14,136 33 0 0 425




1258A-43R-1, 123–128 400.6 20,135 57 0 0 353 19,077 48 0 0 399
1258B-45R-4, 0–5 400.8 14,961 57 0 0 262




1258C-17R-2, 0–5 400.8 60,245 253 0 4 238




1258C-18R-2, 0–5 405.4 36,958 130 0 0 284




1258B-46R-4, 0–5 406.2 19,010 75 0 0 253




1258A-44R-1, 115–120 410.3 9,882 22 0 0 443 4,077 10 0 0 392
1258C-19R-2, 0–5 410.3 19,409 88 0 0 221




1258B-47R-3, 139–144 411.0 5,162 10 0 0 501




1258B-48R-1, 0–5 412.7 23,859 81 0 0 296




1258C-20R-1, 0–5 413.7 43,245 179 0 0 242




1258B-49R-2, 0–5 418.2 8,556 21 0 0 411




1258C-21R-1, 120–125 419.9 28,587 122 0 0 235




1258A-45R-1, 123–128 419.9 9,004 34 0 0 267 436 4 0 0 120
1258B-50R-2, 0–5 423.7 38,317 130 0 0 294




1258C-22R-2, 100–103 425.4 24,661 158 0 12 156




1258A-46R-4, 0–5 427.3 33,531 180 0 19 187 11,716 107 1 13 109
1258B-51R-1, 140–142 427.7 58,740 190 0 11 310




1258A-47R-1, 145–150 429.8 64,888 254 1 28 256 2,478 23 0 0 110
1258C-23R-2, 142–144 431.0 54,662 248 0 19 221




1258B-52R-2, 65–70 433.7 55,707 231 0 25 241




1258A-48R-1, 134–139 434.2 3,821 37 0 5 103 4,698 41 0 6 116
1258C-24R-2, 100–101 435.3 6,310 35 0 3 181




1258B-53R-1, 85–90 436.8 16,844 62 0 6 272




1258C-25R-1, 144–145 439.3 36,627 237 0 26 155




1258A-49R-2, 141–146 440.8 41,050 230 1 35 179 18,643 124 1 17 151
1258C-26R-2, 0–5 443.5 43,237 246 0 31 176




1258B-54R-2, 137–142 444.3 30,365 224 0 40 136




1258A-50R-2, 138–143 445.1 23,895 110 0 13 218 35,519 194 1 28 183
1258B-55R-4, 48–53 449.1 13,783 97 0 12 142




1258C-27R-2, 145–150 450.4 24,694 125 0 12 197




1258C-28R-1, 145–150 453.3 11,454 64 0 6 179




1258B-56R-3, 80–84 453.9 61,530 513 1 96 120




1258B-57R-2, 0–5 456.7 30,292 219 0 38 138




Unit V (clayey chalk with organic matter):








1258C-29R-2, 0–5 458.3 41,833 233 0 24 180




1258C-30R-2, 145–150 464.1 34,310 316 0 44 109




1258C-31R-2, 0–5 467.9 44,261 283 0 27 156




1258C-32R-2, 0–5 472.4 26,691 192 0 13 139




1258C-33R-2, 0–5 477.5 10,206 125 0 10 81




1258C-34R-2, 0–5 482.2 30,537 189 0 11 161




Note: C1 = methane, C2 = ethane, C2= = ethylene, C3 = propane.