The Kochkar Ore Region (Southern Urals): A Typical Representative of Suture Zones with Complex Mineralization

摘要

Genetically different suture zones (Fig. 1) have attracted the attention of many researchers and applied geologists. Such zones will continue to be a major focus of interest for a long time for the following reasons: (1) They represent very intricate geological formations (shear zones and specific megabreccia) related to compression and extension as a result of the linear destruction of large blocks of the Earth's crust. This process was accompanied by crushing, metamorphic-metasomatic alteration, and structural-textural transformation of country rocks (clustering of auxiliary fractures, fault-line jointing, and boudinage). (2) The early collision stage promoted the formation of gold deposits of the quartz vein type. Gold ores were refined and ore lodes were developed at the late stage. Mantle-derived fluids enriched in Au and associated elements may also have been introduced at a late stage. (3) The suture zones are marked by the development of specific drag structures (diverse folds in both ores and metasomatites) and intense jointing zones related to tectonic stress release in the form of oblique faulting. (4) The suture zones incorporate areas with the linear and nonlinear types of mineralization. The linear type includes the normal potassic granites, associated pegmatites (with rare metals), greisens, and quartz veins (with rock crystals). The nonlinear type includes Au-rich mafic metasomatites related to the mantle-derived fluids and other mineragenic forms.