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The Ediacaran organic-rich Doushantuo Shale in the Yichang area of the Middle Yangtze Platform has attracted significant attention, although few studies have focused on the methane adsorption capacities of this new shale. Hence, geochemical and mineralogical analyses, focused ion beam-scanning electron microscopy, and high-pressure (up to 32 MPa) methane adsorption analyses of the Doushantuo Shale selected from the Yichang area were investigated to clarify its nanopore characteristics, methane adsorption capacity, and influencing factors. Our results provide critical new insights into the kerogen and bitumen pore characteristics and methane adsorption capacity of this new shale. Kerogen, bitumen, and inorganic minerals have their own pore development characteristics, which have been observed from SEM images. The large-scale kerogen particles exhibited alignment with elongated shapes with relatively small organic matter (OM) pores or no visible OM pores; however, the bitumen particles have abundant elliptic-like OM pores with a complex structure. The calculated maximum absolute adsorption amounts ranged from 0.70 to 6.58 m3/t and from 0.69 to 5.27 m3/t, respectively, using the supercritical Dubinin-Radushkevich and Langmuir models, which were smaller than those of the Ordovician-Silurian Wufeng-Longmaxi and some typical North America Shales. The influencing factors included pore structure, total organic carbon (TOC) content, OM characteristics, and clay minerals. Moreover, TOC content and OM characteristics predominate on the methane adsorption capacity followed by pore structures, clay minerals, and other factors.

Submarine landslides have affected the mid-Norwegian margin since the Last Glacial Maximum. However, the role of tectonic movements, and most especially fault reactivation, in generating landslides offshore Norway is largely unconstrained. This study uses high-quality three-dimensional seismic and borehole data to understand how landslide development is controlled by faults propagating within the uplifted south Modgunn arch. Variance and structural maps above the south Modgunn arch show that: (1) local scarps of recurrent landslides were formed close to the largest faults, and mainly above strike-slip faults; (2) distinct periods of fault generation were associated with tectonic events, such as the breakup of the northeast Atlantic Ocean, and those events forming the south Modgunn arch; and (3) important fluid-flow features coincide with faults and sill intrusions. In total, 177 faults were analyzed to demonstrate that fault throw values vary from 10 ms to 115 ms two-way traveltime (8 m to 92 m). We propose that the long-term activity of faults in the study area has contributed to fluid migration, weakened post-breakup strata, and controlled the development of submarine slope instability. In particular, strike-slip faults coincide with the locations of several Quaternary landslide scars near the modern seafloor. Similar processes to those documented in Norway may explain the onset of large-scale landslides on other continental margins.