Evolution of physical property of deep-water sediments induced by bio-chemical diagenesis at the Shimokita-Hachinohe coal-bed basin

2014 Fiscal Year Final Research Report

• Project/Area Number: 25800284
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: TANIKAWA Wataru 独立行政法人海洋研究開発機構, 高知コア研究所, 主任研究員 (70435840)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: 間隙率 / 熱物性 / 水分活性 / 地下生命圏 / 続成作用 / 褐炭層 / 堆積盆地

Outline of Final Research Achievements

Microbial biomass in the deep ocean sediments is controlled by physical properties. Therefore, in this study, a series of physical property measurements (Thermal property, porosity, permeability, and water activity) were conducted on the sediment cores at site C0020 from IODP expedition 337 and at site 902 from the Chikyu shakedown cruise (CY06-06) in Sanriku-oki basin. Thermal property measurement revealed that temperature at depth is mainly controlled by the porosity and mineral composition of sediments. Water activity was very high for all the sediment, and we found that chemical composition of pore water controls the water activity. Positive correlation between porosity and microbial biomass was clearly observed, though the relationship between water activity and biomass was unclear. Our result suggests that porosity and pore diameter will mainly control the microbial activity at depth.

Free Research Field

実験岩石力学