Magma superflows in the Bering Sea. 2. The mechanism of origin and movement and its evolution in time and space

Abstract

It is shown that the source for numerous magma superflows (MSFs) with complex structures, whose traces have been identified in the Bering Sea (Melekestsev and Slezin, 2017), was regional mantle plume-like formations (or plumes). The magmatic material propagated from these for some hundreds of kilometers or farther along interfaces at different depths between crustal layers during n × 105 to n × 106 years. The long-continued generation and multi-portion structure of the MSFs is explained by slow pulsations in the rising jet of primary melt in the form of a beaded (“peristalsis-like”) structure of successive bulges (which we shall refer to as “magmons”), which float up as “asthenoliths” as the through flow in the channel becomes lower. The most extensive and longest MSFs were formed at the end of the Eocene through Oligocene, while the youngest and shortest flow was generated in the Pleistocene.