Influence of Global Glaciation on the Origin of Hydrothermal Activity within the Mid-Atlantic Ridge

Sea level changes during of Earth's glacial periods the reduce hydrostatic pressure on the ocean bottom. The decrease in hydrostatic pressure increases magmatic activity and, as a result, could lead to the formation of hydrothermal systems [9, 19]. Thus, a correlation between glacial periods and the origin of circulating hydrothermal systems is possible. To test the hypothesis about the relationship between the formation of hydrothermal systems and glacial periods, we compared the(230)Th/U age dates of sulfide ores in the northern near-equatorial zone of the Mid-Atlantic Ridge and marine isotopic stages, which reflect glacial and interglacial periods. The comparison shows that the glacial periods coincide only with the onset of formation of ore objects associated with basalts within magmatic segments of the Mid-Atlantic Ridge. Conversely, the periods of formation of ore objects associated with tectonic segments of the ridge within oceanic complexes are unrelated to glaciation. We hypothesize that the relationship between glaciations and the origin of hydrothermal systems is determined by differences in the geological conditions for the formation of seafloor massive sulfides within slow-spreading ridges.