From Kenorland to Modern Continents: Tectonics and Metallogeny

Аннотация

There are three stages in tectonic evolution of the Earth: (1) nucleation, from the origin of protocratons to their assembly into the Kenorland supercontinent (2.7–2.5 Ga); (2) cratonization, from the breakup of Kenorland (2.45 Ga) to the assembly of Columbia (1.85 Ga) and its reorganization into Rodinia (1.0–0.72 Ga); and (3) modern plate tectonics, from the breakup of Rodinia 720 Ma until the present. Analysis of the time-space reorganizations of Archean granulite–gneiss terranes, which correspond to continental lithospheric keels, reveals five groups of protocratons (Nena, Ur, Congo–Sahara, NAsia and Atlantica) that remained almost intact during long time intervals. After the breakup of Kenorland, the continental crust rotated counterclockwise. NAsia and Atlantica rotated the least and drifted relative to Nena; however, the latter rotated by 180^○. Congo‒Sahara, Ur, and Kalahari rotated the most. The assembly and breakup of the supercontinents clearly correlates with secular changes in dominant types of base, precious, and ferrous metal deposits, as well as the formation and emplacement of diamonds.