METALLOGENY OF COPPER AND IRON DEPOSITS IN THE EASTERN YANGTSE CRATON, EAST-CENTRAL CHINA

The Eastern Yangtse Craton of central to eastern China is an important Fe-Cu metallogenic province. Based on studies of the regional geology and tectonic evolution, this metallogenic belt is controlled by fault s and aulacogens in the continental plate. In the Early Yanshan Epoch (Jurassic), the dominant west-northwest and east-west lithospheric fau lts controlled the distribution of Cu (Mo, and Au) mineralization, whe reas in the Late Yanshan Epoch (Cretaceous) the north-northeast and no rtheast lithospheric faults controlled Cu-Fe mineralization. In a mine ral district, the distribution of ore-fields is under the dual control of basement fault(s) and near-surface fault(s). Based on the relation of ring and lineament faults to intrusions, a 'three-level' model of vertical zonation is proposed. Systematic petrochemical studies of Mes ozoic igneous rocks and mineralization identify three subseries: (1) a calc-alkaline, intermediate to silicic subseries rich in potassium; ( 2) a calc-alkaline, intermediate to felsic subseries rich in sodium; a nd (3) a calc-alkaline, intermediate to mafic subseries rich in sodium . Genetic types of ore deposits are diverse, including Fe and Cu skarn s, Cu porphyries, Fe ore magma injections, Ningwu-Luzong Fe deposits ( from late orthomagmatic to pegmatitic-pneumato-hydrothermal, and to me sothermal-epithermal) associated with subvolcanic rocks, and remobiliz ed sedimentary Fe and/or Cu deposits. The genetic types of ore deposit s form two metallogenic series: (1) a sedimentary metallogenic series (active mainly in the Paleozoic), and (2) a magmatic-hydrothermal meta llogenic series consisting of three subseries (active predominantly in the Jurassic and Cretaceous), with the latter being more important in this region. The superposition and compounding of these two metalloge nic series contribute to many styles of mineralization in this mineral province.