Internal structure of placer gold in the middle Lena River basin,Southeastern Siberian platform

The internal structure of placer gold depends on its residence time under exogenetic conditions. Two types of placer gold are distinguished in the middle Lena River basin by typomorphic features. Gold of distal transfer (type I) is characterized by recrystallized structure, deformation lines, and thick high-fineness rims indicating long-term residence under exogenetic conditions; and multifold redeposition in transitional reservoir rocks. Gold of proximal transfer (type II) is characterized by a vague zonal structure, thin or discontinuous high-fineness rims, granulation, and disintegration structures indicating short-term residence time under the exogenetic conditions. Gold of proximal transfer is spatially confined to the zones of ancient long-living faults. Thus, it is possible to suggest that this type of gold might have derived from local Middle Paleozoic or Mesozoic gold sources.