Seafloor activity and deep-subsurface geology of gas hydrate areas revealed from δ13C of methane-derived authigenic carbonates along the eastern margin of the Sea of Japan

Hiruta, Akihiro; Matsumoto, Ryo

doi:10.1016/j.margeo.2023.107124

Cited by 2 publications

(4 citation statements)

References 80 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Gas hydrates in near-seafloor sediments (shallower than 5 mbsf) were collected using piston coring (a nonpressurizing tool) during other expeditions and stored in liquid N 2 . 61 These were treated in the same manner as the drilling samples.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…For computed tomography, gas hydrate samples were removed from liquid N 2 for approximately 20 min and returned to liquid N 2 storage for future studies including Raman analysis. Gas hydrates in near-seafloor sediments (shallower than 5 mbsf) were collected using piston coring (a nonpressurizing tool) during other expeditions and stored in liquid N 2 . These were treated in the same manner as the drilling samples.…”

Section: Methodsmentioning

confidence: 99%

“…Sites PC1701 and PC1806 were located approximately 20 km east of the Umitaka Spur, whereas site PC1804 was approximately 90 km northeast of the spur. Chunks, veins, and layers of microbial CH 4 hydrates (approximately −70 ‰ VPDB) exist in the near-seafloor sediments (Hiruta and Matsumoto 61 and Figure S1). Gas seepages that seemed weaker than those at the Umitaka Spur were recognized in the furthest area.…”

Section: ■ Geological Settingsmentioning

confidence: 99%

“…(a) Gas hydrate mounds on the central part were selected as the focus of this study. Sediment cores containing massive gas hydrates and methane-derived authigenic carbonates were collected by piston coring. ,, Red lines indicate sub-bottom and seismic profiles shown in Matsumoto et al Because of the characteristics of the project, details regarding drilling sites are confidential. PC1701, PC1804, and PC1806 indicate locations of piston coring where near-seafloor gas hydrates were recovered.…”

Section: Geological Settingsmentioning

confidence: 99%

See 3 more Smart Citations

Gas Migration through the Crystal Lattice of Gas Hydrates during Sedimentation in Geological Time Scale

Hiruta,

Jin,

Matsumoto

et al. 2024

Energy Fuels

Self Cite

View full text Add to dashboard Cite

Massive gas hydrates recovered from various sediment depths at the Umitaka Spur in the Sea of Japan were studied using Raman spectroscopy to determine their burial diagenesis, particularly those initially grown at shallow sediment depths. The samples recovered from sediment depths within 20 m below the seafloor (mbsf) were enriched in H 2 S. These depths were greater than the present sulfate−methane transition (SMT) zone distributed within approximately 1 mbsf of the coring area. The anaerobic oxidation of methane within the SMT is generally the only potential source of high H 2 S at these depths, whereas the deepening of the SMT to approximately 20 mbsf, greater than that of the reference areas, is improbable. A potential scenario for the depth discrepancy is the sedimentation of gas hydrates that originally grew around the near-seafloor SMT. The CH 4 cage occupancy ratio in each sample becomes <1.08 at sediment depths deeper than 40 mbsf. The more homogeneous CH 4 distribution within the gas hydrate at greater depths is attributed to the longer duration of CH 4 migration through the lattice cage of the gas hydrate. The lack of H 2 S in samples at greater depths could also be attributed to the more homogeneous distribution of H 2 S by migration and escape from gas hydrates at H 2 S-depleted environments.

show abstract

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: ■ Geological Settingsmentioning

confidence: 99%