ANALYSIS OF MAJOR METALLOGENIC SYSTEMS IN WESTERN SECTION, NORTHERN MARGIN OF NORTH CHINA PLATFORM

This paper addresses the geological evolution and tectonic zonation of the northern margin of North China platform where are successively distributed from the south to the north the Wulashan Seertengshan Daqingshan intracontinental upwarping zone, the Dongshengmiao Chaertaishan intracontinental rift, the Langshan Shihahe pericontinental upwarping zone, the Huogeqi Bayan Obo pericontinental rift, the Bainaimiao Baiyindusi rift and upwarping zone, the Wenduermiao Ailigemiao rift. This paper analyzes the pericontinental basement formation and rift sedimentary formation, classifies the rift sedimentation during the splitting and subsiding periods. In addition, this paper deals with the metallogenic system. The identity and the successiveness of the metallogenic material sources are used for the classification of the metallogenic system as four subsystems as shown below: (1) The metallogenic system of metamorphic gold deposit established on the basis of material sources of greenstone formation and composed of various ore deposit type assemblages. This system occurs mainly in the metamorphic area of the upwarping zone in the palaeo continents. (2) The SEDEX metallogenic system in the marine volcanic spilite. This system, mainly composed of Cu Pb Zn polymetallic deposits and mainly occurring in the volcanic rock formation shaped during the rift splitting period, is related to the hydrothermal erupting in the same period of magmas produced in the volcanic activity. (3) The metallogenic system of the spout telescoped deposit in the alkaline rock and carbonatite. This system occurred early in the alkaline volcanic carbonatite of the Bayan Obo rift, with the spout sediments of high temperature silica potassium hydrothermal solution, resulting in the rare element REE iron telescoped deposits. The main ore deposit and the east ore deposit underwent strong weathering and denudation, and alluvial enrichment occured since Cenozoic era.