On Volcanism and Tectonics in the Evolution of the Guyots of the Magellan Seamounts (Pacific Ocean)

Abstract

This report analyzes original geological materials on the Magellan Seamounts in the Pacific Ocean, obtained by the authors on numerous cruises of the R/V Gelendzhik. This chain of guyouts does not have a common volcanic basement and apparently formed in the second half of the Early Cretaceous on the oldest (Middle–Late Jurassic) fragment of the Pacific Plate. The main viewpoints on the genesis of the Magellan Seamounts are as follows: either they originated at the intersection of fracture zones or the Pacific Plate moved them from the Southern Hemisphere to their present-day position. Because of their high degree of study, the Magellan Seamounts are one of the key sites for understanding the mechanism underlying the origin of linear chains in the ocean. A comprehensive analysis of new geological data on the Magellan Seamounts has established the important role of magmatism and tectonics in the formation of the modern morphological forms, sedimentation, and influence on the paleoceangraphy. The periodic reactivation of these processes from the Early Cretaceous to Late Cenozoic can be traced in the cyclicity of sedimentation, the continuous growth of ore crusts, and the formation of secondary volcanic domes and cones.