15:45 〜 16:00
[MIS20-07] Authigenic carbonates related to oil seepage from seafloor sediments – Geologic archives of unique geobiologic ecosystems
★Invited Papers
キーワード：Cold seeps, Oil seeps, Authigenic carbonate, Carbon cycle
The seepage of hydrocarbons from marine sediments induced by persistent upward migration of oil and gas towards the sea floor represents a poorly quantified source of fossil organic carbon in the ocean. Methane and oil seepage at marine seeps creates mud volcanoes, brine pools, gas hydrates and deposits of authigenic minerals, and also supports lush ecosystems on the seafloor. The basis of these ecosystems are consortia of archaea and sulfate reducing bacteria, which perform the sulfate-dependent oxidation of methane and crude oil components. Most seeps at continental margins are dominated
by the seepage of methane, yet many hydrocarbon seeps have been discovered that are characterized by expulsions of crude oil. Such seeps are ideally suited to study the impact of oil seepage on the diversity, activity and distribution of microbial communities, as well as the role of oil seepage and its subsequent degradation for carbonate authigenesis. The interest in the investigation of oil seeps, apart from economic considerations, stems from
the idea that the presence of crude oil could have influenced or even governed the course of evolution of chemosynthetic and chemosymbiotic organisms at seeps through geological time, as the diversity, distribution and lifestyles of seep-dwelling macrofauna today are to a large extent controlled by fluid composition. The presence of crude oil significantly impacts the diversity and distribution of microbial communities at seeps today, and may have done so in the geologic past. Authigenic carbonates, which form during oxidation of crude oil components, are excellent recorders of environmental conditions and metabolic processes that are active at oil seeps, which can be identified by thin section petrography, stable isotope, and trace and rare earth elements geochemistry, and lipid biomarkers.
by the seepage of methane, yet many hydrocarbon seeps have been discovered that are characterized by expulsions of crude oil. Such seeps are ideally suited to study the impact of oil seepage on the diversity, activity and distribution of microbial communities, as well as the role of oil seepage and its subsequent degradation for carbonate authigenesis. The interest in the investigation of oil seeps, apart from economic considerations, stems from
the idea that the presence of crude oil could have influenced or even governed the course of evolution of chemosynthetic and chemosymbiotic organisms at seeps through geological time, as the diversity, distribution and lifestyles of seep-dwelling macrofauna today are to a large extent controlled by fluid composition. The presence of crude oil significantly impacts the diversity and distribution of microbial communities at seeps today, and may have done so in the geologic past. Authigenic carbonates, which form during oxidation of crude oil components, are excellent recorders of environmental conditions and metabolic processes that are active at oil seeps, which can be identified by thin section petrography, stable isotope, and trace and rare earth elements geochemistry, and lipid biomarkers.