Spatiotemporal Pulsations of Plume Activity and Magmatism Overprinted on the Oceanic Lithosphere

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Abstract
The interaction of mobile lithospheric plates and mantle plumes approaching the surface, which have a periodic supply of magmatic material, leads to changes in geological and geophysical characteristics and the appearance of chains and compact groups of volcanoes of different ages in oceans. Data on the relief, Bouguer anomalies, and dating of seamount rocks along hot spot tracks in the Atlantic, Pacific, and Indian oceans show the presence of stable temporal—~1.5, ~3.7, ~4.5‒7.5, and 10‒12 Ma—periods of magmatism powered by different superplumes. These values correspond to the periods of maxima of the spectral density of sea level fluctuations. The same frequency set of these phenomena indicates a single mechanism and time modulation of activity in magma-conveying conduits. Analysis of the times of extrema in the tracks also indicates the compatibility of the periodicity of magmatism in phase. Groups of underwater igneous structures without plate movement tracks in the coordinates of the age of the basement and the analytical age of the rocks form compact but geographically separated groups in this reference system, in the range of all ages of the basement of the Atlantic Ocean, and have a duration of pulses of magmatism overprinted on the basement from 20 to 60 Ma. This and other facts indicate a fixed position of the supply conduits relative to the African Plate on the eastern flank of the Mid-Atlantic Ridge during the Cenozoic. They substantiate the assumption of the general western drift of the lithospheric plates and their displacement from the feeder plume. The pulses of magmatism that are currently continuing in different parts of the Atlantic were preceded by a pause in magmatism from 20 to 60 Ma. Analysis of seismic tomography data allows us to explain the discrete spatiotemporal distribution of magmatic pulses by a combination of a variable regime of vertical supply of heated material with simultaneous horizontal movement of plates.

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