Geological prerequisites for differentiated approach to prospecting and exploration of alluvial gold placers: an example from the northeast of Russia

摘要

A new approach to alluvial gold placers is suggested on the basis of research experience from northeastern Russia. Eight dynamic species of alluvial placers (brush, erosion, apron, perluvial, bar, equilibrium, aggradational, and gravitation) are distinguished based on their genetic geological differences. They are distinct in composition; volumetric structure; morphology in plan and in section; position in river valleys of various sizes; and relation to various morphostructures, gold sources, etc. In rich gold regions with numerous gold sources, the different placers are often combined and form complex placer deposits, the most complex of which occur in large valleys. All placer species and their combinations are characterized. Their features should be taken into account in projection, prospecting, exploration, and exploitation. Some directions for the differentiation of these tasks at different stages are suggested.