Structural position of large gold ore districts in the Central Aldan (Yakutia) and Argun (Transbaikalia) superterranes

Abstract

Gold ore districts in the Siberian (North Asian) craton and bordering terranes have been studied. Studies showed the long duration of gold concentration processes (Early Cambrian to Late Mesozoic and Cenozoic) and the influence of structural geological, magmatic, and metallogenic factors on the formation of ore districts. The largest Late Mesozoic (J–K) accumulations of gold deposits in southeastern Russia were discovered in the Aldan–Stanovoi Shield and at the northern margin of the Argun superterrane in the Aldan (Yakutia), Balei (Transbaikalia), and Gonzha (Upper Amur area) ore–placer districts. The geological and geophysical positions of these three districts have been compared. All of them are situated in zones of influence of variously trending long-lived deep faults, bordered by large Precambrian uplifts, and spatially (paragenetically) related to local magma chamber domes of Late Mesozoic (J–K) intrusive, subvolcanic, and extrusive–effusive bodies, dikes, and terrigenous pyroclastic blankets. The areas of Jurassic–Cretaceous volcanoplutonic rocks are related to the influence of the East Asian sublithospheric “superplume.” All this confirms the important ore-controlling role of large long-lived deep faults (in the form of global and regional gravity gradient zones) in the distribution of highly productive precious-metal ore–magmatic systems. This suggests that the junctions between gravity gradient zones of different trends and ranks are important to the identification of gold prospects in metallogenic prediction studies and small-scale prospecting. The Archean–Proterozoic age and the great occurrence depth of the tectonic zones suggest that extensive long-lived mobile zones (before the post-Cambrian breakup of the Siberian craton) significantly affected further evolution of the orogenic belts bordering the craton and their metallogeny, including the distribution of precious- metal deposits.