(Table 1) Hydrogen- and carbon-isotope compositions of methane and pore water hydrogen-isotope compositions in DSDP Hole 96-618 ...

• Main Authors: Burke, Roger A, Sackett, William M, Brooks, James M
• Format: Dataset
• Language: English
• Published: PANGAEA 1986
• Subjects: Sample code/label; DEPTH, sediment/rock; δ Deuterium, water; δ Deuterium, methane; δ13C, methane; Drilling/drill rig; DSDP/ODP/IODP sample designation; Mass spectrometer Finnigan MAT 250; see references; Leg96; Glomar Challenger; Deep Sea Drilling Project DSDP; Orca
• Online Access: https://dx.doi.org/10.1594/pangaea.788215; https://doi.pangaea.de/10.1594/PANGAEA.788215

Hydrogen- and carbon-isotope compositions of methane (dD-CH4 and d13C-CH4) and pore water hydrogen-isotope compositions (dD-H2O) in several samples from the uppermost 100 m of Orca Basin sediments show little variation with depth and have mean values of - 184, -73.5, and 7 per mil, respectively. The dD-CH4 is typical of that generally found in deep-sea sediments and suggests that the methane was produced biologically almost entirely via the CO2 reduction pathway. Production of small amounts of methane (-15% of the total) from acetate dissimilation cannot be completely ruled out, however. The pore water is more enriched in deuterium than present day Gulf of Mexico deep water, suggesting that the brine found at the bottom of Orca Basin was formed at a time when appreciably more isotopically light water was tied up in continental ice sheets than is at present. The d13C-CH4 values reported here are similar to previously determined brine d13C-CH4, but substantially more enriched in 13C than previously determined ... : Supplement to: Burke, Roger A; Sackett, William M; Brooks, James M (1986): Hydrogen- and carbon-isotope compositions of methane from Deep Sea Drilling Project Site 618, Orca Basin. In: Bouma, AH; Coleman, JM; Meyer, AW; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 96, 777-780 ...