By A.Ya. Kochetkov (Aerogeologiya Enterprise, POB 225, Moscow, 117463, Russia) for Russian Geology and Geophysics, Vol. 47, No. 7
The Aldan Shield (Aldan-Stanovoy area) is an ancient lithospheric plate, which repeatedly interacted with surrounding mobile areas throughout the Phanerozoic. This interaction resulted in numerous igneous-rock and ore associations in the Mesozoic, which form several ore-magmatic clusters and districts. The largest and most commercially important of them is the Central Aldan ore district, which is considered a regional ore-magmatic system (ROMS) within the Aldan Shield, a specific ore-magmatic province. The Aldan complex is a polychronous and polyfacies association composed of diverse igneous, metasomatic, and ore products, which form local ore-magmatic systems (LOMS).
The geologic structure and lithology of the Central Aldan ROMS are typical of a within-plate activity setting. The diversity of igneous rocks in Central Aldan is due to its median localization in the laterally zonal area of Mesozoic magmatism, between alkali-earth rocks in the east and south and peralkaline rocks in the west of the shield. Therefore, this region bears almost all igneous rock varieties of different formations typical of the Aldan province.
There are a number of gold deposits and ore occurrences of different association types within the Aldan Shield. Of practical significance are deposits of four commercial types (El’kon, Ryabinovy, Lebediny, and Kuranakh), the major ones being localized in the Central Aldan ore district. Gold deposits of Central Aldan differ in their localization in the Earth’s crust section. The post-ore block movements of different amplitudes determined the occurrence of these deposits on the modern Earth’s surface or near it. The deposits have both common and different structural and compositional features, which permit them to be referred to different ore associations of a single paragenetic series. The difference in the mineralogy and geochemistry of gold orebodies might be due to different depths of their formation.