РАЗРУШЕНИЕ ДЕЛЬТЫ РЕКИ ТУМАННОЙ В ГОЛОЦЕНОВОЕ ВРЕМЯ И ФОРМИРОВАНИЕ ПРИПОВЕРХНОСТНЫХ СКОПЛЕНИЙ ГАЗА НА ШЕЛЬФЕ ЗАПАДНОЙ ЧАСТИ ЗАЛИВА ПЕТРА ВЕЛИКОГО (ЯПОНСКОЕ МОРЕ)

Abstract

The results of bathymetric and seismoacoustic studies of the shelf in the western part of Peter the Great Bay are presented. Five flooded coastlines formed in the Late Pleistocene-Holocene were identified on the shelf. It was found that a significant part of the shelf is occupied by a zone of irregular sedimentation, which is underlain by an erosion surface buried under sediments of ebb-tidal deltas in areas of active sedimentation and exposed on the seabed within the area of active modern erosion. The processes of abrasion and formation of an irregular sedimentation zone on the shelf intensified about 11500–11700 years ago. Acoustic anomalies associated with the presence of gas in sediments and gas flares in the water column were found on the shelf of the Bay. Anomalies were classified by types, and a map of their areal distribution was compiled. It is concluded that the trigger mechanism that ensures the migration of gas into sediments and water column is associated with a group of factors: postglacial sea level change, abrasion processes, meteorological and hydrological regimes.