The aim of this study was to compare the petrologic data available for the recent tholeiites of oceanic rifts TOR, bathimetry, gravity anomalies, seismicity, and geoid surface in the axial zone of the Mid-Atlantic Ridge MAR. It was found that all of these parameters correlated with one another with the resolution as high as 0.5 of an arc grade in latitude. This correlation was interpreted as the consequence of the interaction of all processes from mantle upwelling to volcanism, which had participated in the formation of a new MAR lithosphere, which was not masked by any later geologic events. It has been proved that the two main geologic environments, corresponding to the simultaneous formation of the TOR spreading and plume rock associations, were distinguished by the highly contrasting scales of mantle upwelling, by the specific magmatism evolution in pressure and temperature, and by the specific distribution of the geophysical fields. This is emphasized by the modal character of the main petrologic and geophysical parameters and is reflected in the geodynamic MAR segmentation. It is shown that the discreteness of the petrologic parameters is a consequence of the discreteness of the external geodynamic conditions, relative to which the magmatism can be ranked as a geologic process of the second order. The productivity of the igneous activity is one of the reliable indicators of the geodynamic environment.
plume, spreading associations, Mid-Atlantic Ridge, petrological and geophysical parameters.
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