Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. Rather than reading a good book with a cup of tea in the afternoon, instead they. These reactions can release to modern seawater up to 20% of the yearly Mg river input. Turcotte Schubert Geodynamics Solutions, but end up in harmful downloads. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. The seawater Mg/Ca ratio increased significantly from, 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite.
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