| Popis: |
Summarizes the materials according to the chemical composition of the volcanic rocks of the Whale Ridge. The analysis showed that the formation of the Eastern and Central parts of the ridge in the Cretaceous and Paleogene was determined, first of all, by the appearance of fractured decompression foci, which arose as a result of shear-thrust dislocations during the split of the Gondwana. Basalts of the Central part of the Whale Ridge have signs of contamination by the crustal matter. Tristan Plume apparently indirectly participated in the formation of the Whale Ridge rocks in the Cretaceous and Paleogene: he partially enriched the melting centers with his material, which originated in the deformed powerful (20 km) crust. The spreading factor manifested itself in the upper Cretaceous (toleite volcanism of the Eastern part of the ridge) and in the Neogene-Quaternary time, when the power of the newly formed oceanic crust began to decrease. This allowed the "fading" Tristan plume to form a system of underwater volcanic mountains in the Western part of the Whale Ridge. |
