Occurrence of gas hydrate in the Chukchi plateau, Arctic

Abstract

<p>The Arctic MArine Geoscience Expedition (AMAGE) program led by the Korea Polar Research Institute (KOPRI) is a multidisciplinary undertaking to investigate the geological environment and methane release phenomena in the Arctic seas. The icebreaking research vessel (IBRV) Araon has carried out three expeditions in the Chukchi Plateau (CP) and the East Siberian Seas in 2016, 2018 and 2019. In the first 2016 expedition, a chain of topographic mounds (with the height of several tens meters and the width of hundreds meters) was identified by subbottom profiler and multibeam bathymetric survey in the western continental slope of the CP. Gas hydrate samples were first retrieved in the Araon Mound-6 among the mound structures in the CP and ESS areas during the expedition. The detailed morphology and subsurface structures of the mounds were mapped from the subsequent expeditions in 2018 and 2019. More gas hydrate samples were obtained in the Araon Mound-3 and Araon Mound-6 in these expeditions. To examine gas hydrate occurrence conditions, we conducted geophysical surveys including seismic (sparker in 2018 and multi-channel in 2019) and heat flow methods during these expeditions. The seismic profiles obtained using two seismic methods show very well-developed bottom simulating reflectors (BSRs) which are widespread on the western slope of the study area. The BSR depths detected on the seismic profiles are well coincided with the depths of the lower boundary of the gas hydrate stability zone calculated from the geothermal gradient of heat flow measurement.</p><p>Arctic gas hydrates are considered to be vulnerable to the ongoing rapid Arctic warming. The AMAGE program will provide comprehensive understanding on poorly-known gas hydrate in the Arctic in the various research fields of geology, geophysics, geochemistry, biogeoscience, and oceanography.</p>