2. CARBON, HYDROGEN, AND OXYGEN ISOTOPE DISTRIBUTION IN THE INTERSTITIAL FLUIDS OF ODP LEG 104, HOLES 642B, 642D, 643A, AND 644A, VORING PLATEAU, NORWEGIAN SEA

• Main Authors: O Eldholm, J Thiede, E Taylor
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1989
• Subjects: Norwegian Sea
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1087.8776; http://www-odp.tamu.edu/publications/104_SR/VOLUME/CHAPTERS/sr104_12.pdf

ABSTRACT Carbon, hydrogen, and oxygen isotope ratios determined on 32 squeezed interstitial fluid samples show remarkable variations with depth. For the most part these variations are related to diagenetic and alteration reactions taking place in the sediments, and in the underlying basalts. 5 13 CECO2 depth distributions at Sites 642 and 643 are the result of mixing of original EC0 2 of the paleo bottom water with EC0 2 released by remineralization of organic matter. At Site 644, where sulfate exhaustion occurs, the processes of methanogenesis by C0 2 reduction and anaerobic methanotrophy strongly influence the S 13 CECO2 distribution. Hydrogen and oxygen isotopes roughly covary, and become enriched in 16 0 and 'H with depth. This effect is most pronounced at Sites 642 and 643, possibly due to the influence of the directly underlying basalts. Isotope depletions at Site 644 are much lower, corresponding to the greater sediment depth to basement. The alternative, that the O, H isotope shifts are due primarily to autochthonous diagenetic and exchange reactions, is not supported by the data available.