Occurrences of benthic foraminiferal fossil Rutherfordoides sp. in gas hydrate bearing areas of the Japan Sea
Abstract
Benthic foraminiferal fossils, Rutherfordoides sp., were recently discovered from the deep sea cores taken from some gas hydrate bearing areas in the eastern margin of the Japan Sea. Since the carbon isotope of foraminifers in the low sea level period during Last Glacial Maximum (LGM) shows a negative anomaly, the existence of this foraminiferal fossil might suggest the existence of past methane seepage. Study core sediments used for the geochemical and paleontological analysis are sampled at various places such as mounds, pockmarks and slopes from offshore Joetsu, and show different sulfate-methane transition (SMT) based on pore water analysis. Rutherfordoides sp was newly confirmed from some cores with the shallow SMT and Ba front around a seep mound of the Torigakubi Spur (water depth around 600m). The 14C age of the planktonic foraminifera extracted from the same sample is somewhat younger than those at deeper sites (water depth around 900m) such as the Umitaka Spur.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS23D1658O
- Keywords:
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- 3004 Gas and hydrate systems;
- MARINE GEOLOGY AND GEOPHYSICS