Thoughts on the evolution of modern oceans

Abstract

Explanation o f the evolution of the Earth's oceans, particularly the processes involved in the generation of the oceans, are important for understanding the general appearance of our planet, and for the solution o f specific problems. A compara tive study o f the world's oceans shows there is a single genetic series in the evolution of oceans, and that the oceans of the world are at different stages in their evolution. The Arctic Ocean, dated as Cenozoic, is noted for its small size and shallow oceanic floor, extensive but passive continental margins, limited volcanism, significant crustal thickness, and a lack of Benioff zones. The Mesozoic, Indian and Atlantic oceans have much greater dimensions and depths than the Arctic Ocean, the crust is thinner beneath them, volcanism is much more extensive, and active margins, while in the initial phase of evolution, are limited in extent. The area of the most ancient (probably Paleozoic) Pacific Ocean is equal to the sum o f the rest of the three oceans; it also has the greatest oceanic depth. Beneath the Pacific, the crust is thinned and is characterized by high permeability, because of which magmatism is particularly widespread. Active continental margins are also extensive in the Pacific. The concept of evolutionary development of the oceans enables us to predict the comparative potential of oceans with regards to their oil and gas and ore content.

Sulphide-Magnetite Ores of Folded Areas as Possible Analogues of Current Oceanic Sulphide Formatios

“…Поставка рудного материала связывается с активизацией базитовых магм на уровне астеносферы в мантии. На завершающем этапе транспортировка и осаждение рудного материала контролируются вертикально неоднородной водной толщей, осуществляющей функции геохимического барьера, промежуточного накопителя и продуцента рудных образований на поверхности океанского дна [3,11]. Источником рудного вещества для океанических руд считаются базальты океанического ложа, через которые путем конвективного рециклинга по зонам трещиноватости в рифтовых системах океаническая вода проникает на глубину до 5 км, нагревается, взаимодействует с вмещающими породами и выщелачивает из них металлы, превращаясь в рудоносный высокотемпературный раствор.…”