(Table 1) Gas molecules, isotopic composition and delta Deuterium in DSDP Holes 95-603D and 95-613

Methane is the major hydrocarbon gas measured in Vacutainer samples from Holes 603D and 613 ( C1/sumCn > 0.999). In Hole 613 the concentration of this dry hydrocarbon gas is highest (7.4 x 10 **5 ppm max.) in the upper 60 to 120 m, then decreases erratically to low trace levels by 261 m sub-botto...

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Bibliographic Details
Main Authors: Whiticar, Michael J, Faber, Eckhard
Format: Dataset
Language:English
Published: PANGAEA 1987
Subjects:
95-603D
95-613
C1/(C2+C3) hydrocarbon ratio
C1/total hydrocarbon ratio
Deep Sea Drilling Project
DEPTH
sediment/rock
DRILL
Drilling/drill rig
DSDP
DSDP/ODP/IODP sample designation
Elevation of event
Ethane
Event label
Glomar Challenger
Latitude of event
Leg95
Longitude of event
Methane
North Atlantic/CONT RISE
North Atlantic/RIDGE
Number
Sample code/label
δ13C
δ Deuterium
water
North Atlantic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.788516
https://doi.org/10.1594/PANGAEA.788516
Description
Summary:Methane is the major hydrocarbon gas measured in Vacutainer samples from Holes 603D and 613 ( C1/sumCn > 0.999). In Hole 613 the concentration of this dry hydrocarbon gas is highest (7.4 x 10 **5 ppm max.) in the upper 60 to 120 m, then decreases erratically to low trace levels by 261 m sub-bottom (lower Pliocene). No gas accumulations were observed in older sediments. Methane from both holes is strongly depleted in both 13C (d13C, - 75 to -85 per mil) and deuterium (D/H, - 175 to -262 per mil), indicating the biogenic origin of the methane. The C and H isotopic compositions support methanogenesis via the CO2-reduction pathway; this is also corroborated by the dissolved-sulfate and alkalinity minima at these depths. The relationship between D/H of the methane and coexisting interstitial water from Site 613 further show the methanogenesis to be primarily by CO2 reduction.

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