New high-resolution 2D seismic imaging of fluid escape structures in the Makran subduction zone,Arabian Sea

作者：Bin Liu,Jiang-xin Chen,Syed Waseem Haider,Xi-guang Deng,Li Yang,Min-liang Duan

摘要：Seabed fluid escape is active in the Makran subduction zone,Arabian Sea.Based on the new highresolution 2D seismic data,acoustic blanking zones and seafloor mounds are identified.Acoustic blanking zones include three kinds of geometries:Bell-shaped,vertically columnar and tilted zones.The bellshaped blanking zone is characterized by weak and discontinuous reflections in the interior and upbending reflections on the top,interpreted as gas chimneys.Vertically columnar blanking zone is interpreted as side-imaged gas chimneys associated with focused fluid flow and topped by a seafloor anomaly expressed as a localized reflection discontinuity,which may together serve as a vent structure.Tilted acoustic blanking zone could be induced by accretionary thrust activity and rapid sedimentation surrounding slope.Seafloor mounds occur at the sites of bell-shaped acoustic blanking zone and may be associated with the material intrusion.Bottom simulating refectors(BSRs)are widely distributed and exhibit a series of characteristics including diminished amplitude,low continuity as well as local shoaling overlapping with these acoustic blanking zones.The large amount of gases dissociated from the gas hydrates migrated upwards and then arrived at the near-seafloor sediments,followed by the formation of the gas hydrates and hence the seafloor mound.

發文機構：Key Laboratory of Marine Mineral Resources Key Laboratory of Gas Hydrate Laboratory for Marine Mineral Resources National Institute of Oceanography Key Laboratory of Submarine Geosciences and Prospecting Techniques

關鍵詞：MAKRANFluidescapestructureGashydrateGaschimneySeafloormoundMarinegeologicalsurveyengineeringPakistanArabianSea

分類號： P73[天文地球—海洋科學]