The Relationship between Magmatic and Tectonic Processes in the Formation of the Oceanic Crust to the South of the Charlie Gibbs Fracture Zone (North Atlantic)статья
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Дата последнего поиска статьи во внешних источниках: 20 февраля 2024 г.
Аннотация:This article presents new data on the structure and relationship of tectonic and magmatic processes during the formation of the Mid-Atlantic Ridge between the Charlie Gibbs and Maxwell Fracture Zones in the North Atlantic. It is shown that this region is characterized by significant reduction in volcanism, which leads to the uplift of deep-seated rocks (ultramafic rocks and compositionally diverse gabbroids) to the seafloor surface. Both separate oceanic core complexes of the most varied configurations and extended sublatitudinal ridges composed of plutonic rocks are formed. Our analysis showed that this geodynamic regime exists during at least 14–16 Ma. The formation of most oceanic core complexes is associated not only with tectonic factors, but also with the serpentinization of peridotites, which leads to a decrease in density, an increase in volume, and, as a result, to the ascent of large ultramafic massifs, including disintegrated blocks of gabbroids, dolerites, and basalts. Numerous zones of sliding, crushing, abrasion, and deformation of rocks are evidence of tectonic movements. The area of study is characterized by numerous nontransform displacements of different amplitudes, which resulted due to relative displacements of oceanic lithosphere segments in wide areas under shear and extension conditions. The morphology of the forming tectonomagmatic structures is determined by tectonic factors. The exceptions are cases where the volumes of basalt melt that come to the seafloor surface for a short period of time are significantly higher than the average ones for a certain segment of the rift valley. The analysis we performed shows the presence of sources of heterogeneous magnetic anomalies both of volcanic origin and those associated with superimposed tectonic processes.