Ocean floor structure in the junction area of the King Trough and the Azores-Biscay Rise (North Atlantic)

The paper, based on geological and geophysical data obtained during 55-th expedition of the research vessel “Akademik Nikolaj Strakhov”, examines the structure of the King’s Trough and its immediate surroundings (King’s mesostructural cluster), located on the eastern flank of the Mid-Atlantic Ridge in the North Atlantic. Six provinces were identified within the southeastern part of the King’s Trough, based on the results of bathymetric mapping, each of which has its own morphostructural appearance, which was formed as a result of multistage tectonic and volcanic processes, alternating and conjugate with each other in time. According to seismoacoustic profiling data, three main types of seismic faces have been identified: a) pelagic complexes; b) deposits of turbidite flows; c) chaotic facies of gravitational genesis. It is shown that the anomalous magnetic field of the study area is a superposition of linear and isometric anomalies. The first were formed during the generation of oceanic crust in the axial spreading zone. The second are associated with volcanic massifs formed in intraplate conditions. The obtained data confirm the assumption that the formation of the King’s Trough was preceded by the formation of an extended arched uplift, which became the scene of intense intraplate volcanism, the intensity of which increased from the southeast to the northwest. This stage was followed by subsidence of the axial part of the uplift with the formation of the King’s Trough and the Peak and Freen Troughs.