Continental crustal evolution and synchronous metallogeny through time in the North China Craton

Abstract

The generation and evolution of continent crust have long been matters of debates. There is evidence to support the view that the first formation of TTGs of continent was possibly before 4.4 Ga, followed by the sizable continent crust associated with BIF-bearing supra-crustal rocks at ca. 3.8 Ga. Multiple stages of continental growth include continental nuclei at ~3.1 Ga, enormous crustal growth at 2.9–2.7 Ga and stabilization and cratonization at ~2.5 Ga. Subsequently a stable super-continent was formed and the Earth was evolved into the Proterozoic eon. In the Proterozoic eon, major geological events include the great oxygen event (GOE), global rift and mobile belt event, and the Earth’s middle age event with a 1.0 billion years long period of Earth’s adjustment or silence. After that, the Rodinian super-continental break up event (the Nanhua rift) and subsequent Gondwana amalgamation have been suggested to be involved with mantle-plume and the modern style-like plate tectonics, both of which are still under debates. Recent studies suggest that the continental metallogeny has secular changes with the evolving Earth, showing synchronous evolution with the continental crust through time. The North China Craton (NCC) is one of the oldest cratons in the world, and has undergone six major tectono-metallogenic cycles: (1) the Neoarchean crustal growth and Algoman-type BIFs-greenstone belt and gold metallogenic system, (2) Paleoproterozoic GOE associated with global (Huronian) rifting- Glaciation and Superior-type BIFs-Mg-B metallogenic system, (3) Paleoproterozoic rifting-subduction-accretion-collision event (mobile belt) and Cu-Pb-Zn metallogenic system; (4) Late Paleoproterozoic – Neoproterozoic multi-stage rifting and REE-Fe-Pb-Zn metallogenic system; (5) Paleozoic orogenesis at the margins of the craton and porphyry Cu-Mo metallogenic system; and (6) Mesozoic extensional tectonics associated with lithosphere thinning and intracontinental Au metallogenic systems. Ore deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities. Changes of metallogenic styles with time, from the dominant BIFs in Archean to polymetallic deposits in Proterozoic and Phanerozoic, demonstrate that the nature and style of metallogeny through time change with different stages of the Earth’s evolution and are the expression of variable materials at the different stages. The changes of metallogeny through time are controlled by the irreversible continental tectonic evolution. The connotation and signification of synchronous evolution of continental crust and mineral deposit systems through time are beyond the study of mineral resources but would provide new insights into the geodynamics of the generation and evolution of the continent. The NCC provides an excellent venue to address the linkage between metallogenic processes and secular changes in the Earth System, including mantle dynamics and crust-mantle interaction on a global perspective.