Faulted Structure of the Bottom Simulating Reflector on the Blake Ridge, Western North Atlantic

• Main Authors: Rowe, M. M., Gettrust, J. F.
• Other Authors: NAVAL RESEARCH LAB STENNIS SPACE CENTER MS
• Format: Text
• Language: English
• Published: 1993
• Subjects: Physical and Dynamic Oceanography; Acoustics; *FAULTS(GEOLOGY); *SEISMIC DATA; *AMBIENT NOISE; TEMPERATURE; SCATTERING; INTERFACES; LAYERS; TOWED ARRAYS; RESOLUTION; PHASE; GEOPHYSICS; METHANE; OCEANS; NOISE; BEARINGS; MIGRATION; NAVAL RESEARCH; PRESSURE; SEISMOMETERS; RIDGES; MULTICHANNEL; DIRECTIONAL; HORIZON; OCEAN BOTTOM; REFLECTORS; SEDIMENTS; BOTTOM; DISCONTINUITIES; BOUNDARIES; REGIONS; PATHS; ARRAYS; REFLECTION; HIGH RESOLUTION; HYDRATES; PE62435N; WUDN259007; Methane hydrate; North Atlantic
• Online Access: http://www.dtic.mil/docs/citations/ADA271289; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA271289

High-resolution multichannel seismic data collected from the Blake Ridge in the western North Atlantic by the Naval Research Laboratory's Deep Towed Acoustics/Geophysics System (DTAGS) show that the bottom simulating reflector (BSR) in this area is the reflection from the interface between an approx. 440-m-thick section of hydrate bearing sediment overlying and approx. 5- m-thick layer of methane gas-rich sediment. The high resolution attainable by the deep-tow seismic system reveals normal fault offsets of approx. 20 m in the BSR. These growth faults may provide a path for vertical migration of methane initially concentrated beneath the hydrate-bearing sediment, enabling hydrate to form throughout sediment above the BSR. Because the BSR represents a methane gas methane hydrate phase boundary rather than a lithologic or diagenetic horizon, the observed off set of the BSR itself reflects discontinuities in the pressure- temperature field across the fault zones where they intersect the BSR. Directional ambient noise, Bottom scattering, Deep-towed array geophysical system, Ocean-bottom seismometer, Towed array. Pub. in Geology, v21 p833-836 Sep 1993. v1 n2 p143-153, 1993.