Slow Dynamics of Hydrate Systems Revealed by a Double BSR

Abstract

Abstract Determining how gas hydrate distribution evolved along continental margins in the past is essential to understanding its evolution in the future. Moreover, hydrate decomposition has been linked to several catastrophic events, including some of the largest submarine landslides on Earth and the massive release of greenhouse gases into the ocean. Offshore Romania, the presence of a second bottom‐simulating reflector (BSR) provides an opportunity to gain valuable insights into hydrate dynamics since the Last Glacial Period (LGP). We conducted transient modeling of hydrate thermodynamic stability by merging in‐situ observations with indirect assessments of sea‐bottom temperature, thermal conductivity, salinity, sedimentation rate, and sea‐level variations. We reveal a strong correlation between the BSRs and the base of the Gas Hydrate Stability Zone (GHSZ) during both the present and LGP periods. The gradual evolution of the GHSZ over the past 34 ka presented here supports a conceptual model that excludes catastrophic environmental scenarios.

Keywords

• hydrates
• free gas
• double BSR
• modeling
• last glacial period
• Black Sea