Geochemical Cruise Report SO226/2 RV Sonne Chatham Rise Expedition.

摘要

The Naval Research Laboratory contributed to an international research expedition to determine the association of methane (CH4) hydrate dissociation with pockmark formation on the Chatham Rise (New Zealand) during previous climate cycles. Piston coring and multi-coring was conducted at four locations with different seismic, multibeam, and physical profiles. Prior to SO226, seismic and multibeam data were obtained by the University of Auckland and IFM-Geomar which helped to identify broad study areas. Seismic and multibeam data collected on Leg 1 (SO226-1) helped to identify specific coring locations. These target areas were determined based on the seafloor morphology and seismic data interpretation of shallow sediments. More specifically, coring locations were selected where seismic profiles suggested high vertical CH4 fluxes to the shallow sediment and at sites that were predicted to have low or nonexistent vertical CH4 fluxes. Sediment cores were also collected in the same locations for paleogeochemical analyses which will be completed by Helen Neil at National Institute of Water and Atmospheric Research, Ltd. (NIWA) in Wellington, NZ. The final assessment of these sediments will require integration of geophysical, geological, and geochemical data.