Behavior of organic matter and gold under conditions of folding deformations

Abstract

The article provides a brief overview of publications on natural organic matter (OM) and its transformation at various stages of the sedimentary rocks conversion. It is demonstrated, that the changes in the composition, structure, and properties of OM were accompanied by changes in the concentration of metals, including gold. The OM and gold behavior under conditions of folding deformations was examined by the authors on the example of the formation of zones of intense folding in large gold-mining re- gions of Russia (Central Kolyma and Baikal-Patom). Plastic deformations of sedimentary rocks are associated with active migration of gold in the composition of soluble OM components. The squeezing and injection structures that arise during the folding ensured the natural multidirectional movement of OM of the lowest viscosity into the areas of decompaction of sedimentary rocks. This migration resulted in anomalous concentrations of gold and OM in the locking parts of the folds. This process was intensely manifested in the terrigenous-shale rock sequence within the Dekdekan zone of folded dislocations (Central Kolyma region), where gold-bitumen mineralization was identified, represented by a large lens-shaped deposit 500–800 × 2500 m in size. The only metal concentrator here is oil-like bitumen forming very fine dissemination in the rock.

Keywords

• carbonaceous rock sequences
• folding deformations
• areas of squeezing and injection
• gold-bitumen mineralization
• gold-sulfide mineralization