Characteristics of the Composite Metallogenic System along the Jilin Paleocontinental Margin and the Evolution of Continental Dynamic Regimes

摘要

In view of the existing problems about the metallogenic epoch and origin of the complex along the Jilin paleocontinental margin, we propose the composite metallogenic system of the Jilin old land, based on the theory of metallogeny and from the continental dynamics and comprehensive analysis on the metallogenic characteristics. Its scientific theory is demonstrated by the following aspects: (1) Screening and analysis of the multi-stage superimposition and sequences. The composite ore-forming system consists mainly of three types: the divergent-type epicontinental metallogenic system on the southern margin, the convergent-type epicontinental metallogenic system on the northern margin and the strike-slip-type epicontinental metallogenic system on the northeastern margin. Their major metallogenic epochs are Archean-Proterozoic, Variscan and Yanshanian respectively. (2) Comprehensive analysis of the genetic relations of the complicated deposits. The above-mentioned three types all indicate a consanguinity among granites, vein rocks and gold deposits, correspondence with geochemical elements, and unicity showing the same activities of mantle-derived fluids and multi-source origin of ore-forming substances. (3) As to the mechanisms for mineral concentration, in addition to the sources, we also focus on the co-actions of permeability, vibration, gas-liquid state alternation and abrupt changes of flow velocity during the movement of ore-forming liquids, as well as the extraction and communication of multi-sequence circulating liquids. (4) It is helpful for establishing the relationship between metallogeny and the evolution of continental dynamic regimes, i.e., the ore-controlling correlations between the ore-forming elements-metallogenic series-metallogenic systems-composite metallogenic system and ore-controlling structural features (stratabound, primary and branching types)-regional faulting or secondary continental extension and collision-transformation of different continental dynamic types (divergent, convergent and strike-slip)-the evolution process of the whole old land for the Jilin old land margin. All these are helpful for further researches on the continental metallogenic dynamics.